VariationofRockMassPressureduringTunnelConstructionin...

Research ArticleVariation of Rock Mass Pressure during Tunnel Construction inPhyllite Stratum

Jianxun Chen1 Yanbin Luo 1 Yao Li 1 Lijun Chen 1 Chuanwu Wang1

Zeguang Song1 and Pengsheng Diao2

1School of Highway Changrsquoan University Xirsquoan 710064 China2Shenzhen China Overseas Construction Limited Shenzhen 518000 China

Correspondence should be addressed to Yanbin Luo lybchdeducn

Received 18 April 2020 Revised 28 June 2020 Accepted 10 July 2020 Published 11 August 2020

Academic Editor M I Herreros

Copyright copy 2020 Jianxun Chen et al(is is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

In this paper the field monitoring method is used to study the variation of rock mass pressure during the construction of a tunnelin phyllite stratum and three functions are used to fit and analyze the variation of rock mass pressure with deformationexcavation time and space (e results show the following (1) When the deformation increases significantly the rock masspressure decreases firstly and then increases (is is caused by the insufficient bearing capacity of the rock mass in the arch foot ofthe supporting structure after the excavation of the upper bench which leads to a settlement of supporting structure andsurrounding rock (2) Compared with other kinds of fitting functions the logistic function can better characterize the variation ofthe pressure of surrounding rock with deformation excavation time and distance from the face (is paper provides a reliablereference for the design and construction of the tunnel in phyllite stratum(e logistic function can be used to present and predictthe change of rock mass pressure with deformation excavation time and space in similar rock mass conditions

1 Introduction

Rock mass pressure is the pressure acting on supportingstructure and it is caused by deformation or loosening of thesurrounding rock after a tunnel is excavated After the ex-cavation of the tunnel the initial stress field of the sur-rounding rock is disturbed and the rock mass pressure entersthe dynamic adjustment stage In the soft surrounding rockthis stage lasts for a long time and the stress and deformationof the tunnel are difficult to be stable for a long time which isnot good for the safety and stability of the overall structure ofthe tunnel [1ndash3] (erefore to assure a safe construction it isimportant to study the changing pattern of rockmass pressureduring tunnel construction In recent years the changingpattern of rock mass pressure during tunnel construction hasbeen studied by analytical method numerical simulation on-site monitoring and laboratory model tests [4ndash12]

By using the analytical method many researchers proposeda newmethod or new coefficient to better predict the change ofthe rock mass pressure Panet proposed a load release

coefficient to describe the load variation during tunnel con-struction It is found that the increase in load is due to therheological behavior of the rock mass [13] Guo et al used avolume loss rate to characterize the variation of tunnel rockmass pressure and found that the volume loss rate and the loadrelease rate in the soil tunnel had a linear relationship [14] Zhaoet al used analytical and numerical solutions to analyze thelining forces of shallow and deep buried soil tunnels It is foundthat different constitutive models of the soil and constructionmethod lead to different rockmass pressure and lining force [8](e analytical solution method can not consider the complexgeological conditions in the process of tunnel construction so itneeds amodel test numerical simulation and othermethods toimprove the practical significance of the study

Model tests are also widely used to analyze the change ofrock mass pressure Li et al used a comprehensive loadrelease rate to study the load release process of tunnel ex-cavation results showed that the whole section should betaken as the research object and the overall load release stateof the section should be analyzed [15] Lei et al used the

HindawiMathematical Problems in EngineeringVolume 2020 Article ID 3918787 15 pageshttpsdoiorg10115520203918787

method of model test to systematically study the change lawsand distribution forms of structural stress and rock masspressure of shallow buried tunnels (e results show that therockmass pressure and structural stress constantly change inthe process of tunnel excavation and the stress release nearthe excavation face is large showing unsymmetrical pressurecharacteristics and time-space effect [16] Huang et alstudied the failure mechanism of soft rock tunnel undersurcharge through the large-scale model test and found thatthe rock mass pressure is mainly concentrated on the roof ofthe tunnel rather than the sidewall [17] Numerical mod-elling is also widely used to simulate the change of the rockmass pressure together with the back analysis Li et almodeled the stress changes during the construction of asubway tunnel and results showed that the rock masspressure near excavation changed significantly until the ringclosure was reached [18] Mark et al used a finite-elementmodel (FEM) to study the distribution of stress strain anddeformation during tunnel excavation And the bearingcapacity of pressure tunnels was determined by the super-position principle [9] Eberhardt researched the near-fieldstress path in the excavation process with a detailed three-dimensional finite-element model (e results demonstratethat the spatial and temporal evolution of the three-di-mensional stress field includes a series of changes ofdeviatoric stress as well as principal stress axis [19] Chenet al studied the change of rock mass pressure during theconstruction of soft rock tunnel through the combination offield monitoring and numerical simulation and found thatthe surrounding rock pressure was stable 65 to 70 days afterthe completion of support structure [20] (e correctness ofthe analytical solution and model test is verified by nu-merical simulation but it is still different from the actualsituation in the field(erefore fieldmonitoring has a strongpractical significance in the process of tunnel research

On-site monitoring plays an important role in theanalysis of rock mass pressure during tunnel constructionHu et al found that the horizontal stress of the bias tunnelwas over released and the measured pressure value of sidewalls was much larger than the calculated pressure value bycomparing the on-site monitoring data with the theoreticalcalculation results [21] Walton et al used LiDAR scan datafor tunnel section analysis and back-calculation A newellipse fitting data analysis method is proposed which can beused to analyze the rock mass pressure distribution of thetunnel section [22] Kontogianni and Stiros analyzed a largenumber of records obtained by electronic theodolite intunnels It proved that the deformation in tunnels would beaffected by the stress release of adjacent parts of the rockmass [23]

In the past a large number of researchers have obtainedthe law that the rock mass pressure decreases with the in-crease of surrounding rock deformation through numericalsimulation and theoretical calculation [24ndash28] (is is dif-ferent from the change rule that the rock mass pressureincreases first and then decreases when the clearance con-vergence and settlement increase rapidly which is moni-toring under the special geological conditions in this paper(erefore further research is needed to provide a theoretical

basis for the design and construction of the tunnel Based onthe monitoring of the Mingyazi tunnel this study analyzesthe variation of rock mass pressure with the deformationtime and distance from excavation face during the con-struction process of the phyllite tunnel and summarizes achanging pattern

2 Project Overview

(e Mingyazi tunnel is located in Shaanxi province It is afour-lane two-tunnel expressway project (e left line tunnelis 4949m and the right line tunnel is 4985m It is anextralong tunnel with a maximum buried depth of 320m

(e monitoring measurement section is selectedaccording to the field conditions (e right line has 9 de-formation monitoring sections including 1 stress moni-toring section and the station number of the stressmonitoring section is YK214 + 011 (hereinafter referred to as011 section) (e main lithology of the monitoring section isgray-black carbon phyllite with low stability and strengthwhich is easy to produce creep and be soften in water Itbelongs to the grade V weak rock mass segment according toldquoTechnical Specifications for Highway Tunnel Constructionrdquo(JTGTF60-2009) [29] (e surrounding rock conditions ofsection 011 are shown in Figure 1

Tunnel construction adopts three-bench and seven-stepconstruction method and its construction sequence isshown in Figure 2 (e construction sequence is to excavatethe arc heading (1) left and right sides of the middle bench(2 3) left and right sides of the lower bench (4 5) and finallyexcavate the three parts of reserved core soil (6ndash1 6ndash2 6ndash3)

(e tunnel is supported by a composite lining Groutedpipe spiling is used for presupport the usually used rockbolts are not used and the feet-lock anchor pipe is installed(e support parameters are shown in Figure 3

3 In Situ Monitoring

According to the requirements of ldquoTechnical Specificationsfor Highway Tunnel Constructionrdquo (JTGTF60-2009)[29] the monitoring contents and methods of the Min-gyazi tunnel are proposed based on its constructionmethods and geological conditions In the monitoring ofcrown settlement and clearance convergence the non-contact measurement method is used to improve themeasurement precision and complete the collection ofmonitoring data in the field Monitoring items instru-ments and sensors are summarized in Table 1 (e de-formation of the monitoring section the layout of themeasuring points and the numbers of the survey pointsare shown in Figures 4 and 5

4 Analysis of Monitoring Results

41 Variation of Rock Mass Pressure and Deformation withTime (e relation between the rock mass pressure andsettlement of the YK214 + 011 section is shown inFigures 6ndash10 (e relation between rock mass pressure andclearance convergence is shown in Figures 11 and 12 Yx

2 Mathematical Problems in Engineering

represents the rock mass pressure at the xth measuringpoint For example Y0 represents the rock mass pressure atpoint 0 of the arch crown in Figure 5

It can be seen from Figures 6ndash10 that there is a certaincorrelation between rock mass pressure and settlementdevelopment In Figures 6 and 7 rock mass pressure

Rock mass

Figure 1 (e field geological condition of the Mingyazi tunnel

1

1 16-1 3

2

4

56-2

6-3

Figure 2 Construction method of the Mingyazi tunnel

Φ820 times 20 mesh rinforcement

Y as drainage half pipe26cm C20 shotcrete

8cm reserved deformation350gm2 earthwork cloth

12mm EVAECB waterproof board45cm molding C25 concrete linding

I20a steel sets = 50

Pipe L = 400

17 Φ50 times 5 grouted pipe spilingL = 300 α = 25deg

Φ22 feet-lock

Figure 3 Support parameters of the Mingyazi tunnel

Mathematical Problems in Engineering 3

increases with the crown settlement but the increasing rateof rock mass pressure is different at Y0 and Y3 InFigures 8ndash10 while the settlement is accumulated rock masspressure increases first followed by a decrease and increaseagain It can be concluded that rock mass pressure generallyincreases with the increasing crown settlement However inFigures 9 and 10 the excavation of the lower bench results ina sharp decrease of the rock mass pressure which is becausethe excavation of the lower bench causes the stress in thesurrounding rock to release with the increase ofdeformation

Figures 11 and 12 show the changes in rock masspressure and convergence It can be seen that convergence issignificantly accumulated mostly after the construction ofmiddle bench (noted by bench excavation in the figures)while the rock mass pressure is accumulated mostly after theconstruction of the lower bench

42 Variation of Rock Mass Pressure with Time (e rockmass pressure monitoring results of the YK214 + 011 sectionand the proportion of the rock mass pressure variation at

Table 1 On-site monitoring measurement project and method of the Mingyazi tunnel

Number Monitoring content Instrument Monitoring frequency

1 Clearance convergence TOPCON (OS-600G) total station1ndash15 days 1-2 timesday

16 days-1 month 1 timeday1 month later 1-2 timesweek

2 Crown settlement TOPCON (OS-600G) total station1ndash15 days 1-2 timesday


3 Rock mass pressure and contact pressure Pressure sensor 1 timeday

Arch vault

Right haunchLeft haunch

Top heading convergence

Maximum excavation line convergence

Right sidewallLeft sidewall

Figure 4 Measured points arrangement of arch settlement andclearance convergence

1

3

2

87

4

5 6

0

Pressure cell

Maximum excavation line

30deg

30deg30deg

24deg

Figure 5 Sensor arrangement for stress monitoring in initialsupport

424 51 58 515 522 529 65 612 619000

001

002

003

004

005

006

Monition time (monthday)

Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation

Lower benchexcavation

Construction of invert

0

20

40

60

80

100

120

140

160

Settl

emen

t (m

m)

Y3Settlement

Figure 7 Rock mass pressure and settlement curve of Y3

424 51 58 515 522 529 65 612 619000

005

010

015

020

Y0Settlement


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)



each stage to the final measured values are shown in Table 2(e relationship between rock mass pressure and time isshown in Figure 13 and the distribution of rock masspressure is shown in Figure 14

(e average changing ratio of rock mass pressure in theconstruction stages of the arch and sidewalls in this sectionare shown in Figure 15

It can be seen from Figure 13 that after the constructionof the upper bench rock mass pressure at the crown (Y0)increases fast and the rock mass pressure at sidewalls (Y4Y5 Y6) increases faster And in Figure 14 the final rockmasspressure at Y0 and Y6 points is relatively high (is is due tothe fact that the upper bench is located at the maximumexcavation line as a result the construction of the middlebench has the greatest influence on rock mass which causesthe dramatic increase of the rock mass pressure at the crownand the sidewalls At this stage the variation of the rockmasspressure at the sidewalls accounts for 33 of the finalmonitored value as shown in Figure 15(b) Figure 15(a)shows that after top heading is excavated rockmass pressureat crown accumulated 32 of its final monitored value androck mass pressure at the crown (Y0) changes rapidly asshown in Figure 13

428 55 512 519 526 62 69 616000

002

004

006

008

010


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)

Y5Settlement


428 55 512 519 526 62 69 616000

005

010

015

020

025


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)

Y6Settlement


421

426 5

1

56

511

516

521

526

531 6

5

610

615

620

000

005

010

015

020

025

Y0Y1

Y3Top heading


Rock

mas

s pre

ssur

e (M

Pa)

0

20

40

60

80

100

120

Clea

ranc

e con

verg

ence

(mm

)

Benchexcavation



Figure 11 Rock mass pressure of arch and clearance convergencecurve of top heading

430 55 510 515 520 525 530 64 69 614 619000002004006008010012014016018020022024

Y5Y6Bench


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

50

100

150

200

250

Clea

ranc

e con

verg

ence

(mm

)

Figure 12 Rock mass pressure of sidewalls and clearance con-vergence curve of the upper bench

424 51 58 515 522 529 65 612 619000

002

004

006

008

010

012

014

016


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

120

140

Settl

emen

t (m

m)

Y4Settlement



It is interesting to note that after the construction of theupper bench and before the construction of the lower benchthe rock mass pressure at each part suddenly drops at thesame time (is is caused by the insufficient support of rockmass at skewback (bottom of the constructed sidewalls) Dueto the limited bearing capacity supporting structure and therock mass move downwards together As a result afterexperiencing the deformation rock mass pressure is de-creased and the loose rock mass around the tunnel becomeslarger followed by further compaction of rock mass withrock mass pressure increase

Figure 13 also shows that after the excavation of thelower bench rock mass pressure increases relatively fast butthe change rate decreases gradually especially after theinstallation of the secondary lining From Figure 15 it can beseen that excavation of the lower bench has little effect on theincrease of rock mass pressure at the arch but has a greaterinfluence on the increase of rock mass pressure at sidewallswhich accounts for 31 of the final monitored value Beforethe construction of invert the rock mass pressure at thecrown and the sidewalls accumulated more than 65 of thefinal monitoring value It should be noted that before sec-ondary lining is installed the rock mass pressure reaches arelative steady state and the state extends after the con-struction of the secondary lining

43 Relation between Rock Mass Pressure and Distance toExcavation Face (e change of rock mass pressure withdistance to excavation face is shown in Figure 16 In Fig-ure 16 D represents the maximum excavation diameter ofthe tunnel For the Mingyazi tunnel D is about 123m Intunnel engineering the rock mass pressure at certain sectionis greatly influenced by both after excavation time anddistance to excavation face (erefore it is important toanalyze the relation between rock mass pressure with thedistance to excavation face In the construction process ofthe YK214 + 011 section the excavation speed was basicallythe same and there was no delay during construction (eprogress was about 2mday As a result the time effect in theprocess can be considered unchanged

From Figure 16 we can see the following (1) When thedistance from the excavation surface is within 1-time tunneldiameter the rock mass pressure changes rapidly (is ismainly due to the fact that the monitoring section is close tothe excavation face where there is a great disturbance to thenearby rock mass (2) When the distance is between 1 and25 times of tunnel diameter the rock mass pressure dras-tically fluctuates which is caused by the complex and longconstruction process

44 Fitting Analysis of Variation Law of Rock Mass Pressure(e relation between rock mass pressure and distance toexcavation face is found in Figure 16 However the data of

Table 2 Monitoring results of rock mass pressure in YK214 + 011 sectionMPa

Monitoringpositions

Before upper benchexcavation

Before lower benchexcavation

Before the constructionof invert

Before the constructionof the secondary lining Final monitoring

valueRock masspressure

Ratio()

Rock masspressure

Ratio()

Rock masspressure

Ratio()

Rock masspressure

Ratio()

Y0 0034 17 0080 39 0174 84 0196 95 0206Y1 0063 54 0066 57 0060 52 0100 86 0116Y2 mdash mdash mdash mdash mdash mdash mdash mdash mdashY3 0013 25 0015 29 0019 37 0052 100 0052Y4 0003 3 0033 37 0078 88 0089 100 0089Y5 mdash mdash 0037 40 0012 13 0064 69 0093Y6 mdash mdash 0046 21 0170 76 0223 100 0223Y7 mdash mdash mdash mdash mdash mdash 0065 155 0042Y8 mdash mdash mdash mdash mdash mdash mdash mdash mdash

000005010015020025

Rock

pre

ssur

e (M

Pa)


Y0Y1Y2

Y3Y4Y5

Y6Y7Y8

Benchexcavation

Lower benchexcavation Construction

of invert

Construction of secondary lining

429 5

6

513

520

527 6

3

610

617

624 7

1

78

715

722

Figure 13 Temporal curve of rock mass pressure in YK214 + 011section

1

3

2

87

4

5 6

0

0206

0022

0089

0223

Damaged

0116

0052

0093

0042

Unit MPa

Figure 14 Distribution of rock mass pressure


deformation excavation time and distance from the face arerelatively obtained data (erefore if one correlationfunction can characterize the pressure of rock mass with thechanging deformation excavation time and distance fromthe tunnel face the development of rock mass pressure canbe predicted accordingly

Taking the YK214+ 011 section of theMingyazi tunnel asan example the relationship between the rock mass pressureand deformation excavation time and distance from thetunnel face is analyzed Origin data analysis software is usedto fit and analyze the rock mass pressure In the analysislogarithmic function sigmoid function and multiplefunctions are used to fit the data and the optimal function isfinally selected to characterize the variation of rock masspressure (e logistic function is adopted to formulate theS-type function and multifunction uses the cubic formu-lation to represent (e basic forms of the functions areshown in equation (1)ndash(3) In the three fitting formulas yrepresents rock pressure x represents settlement and theother symbols are variable parameters as shown in Table 3

y a minus b ln(x+c) (1)

y A1 minus A2

1 + xx0( 1113857p + A2 (2)

y A + Bx + Cx2

+ Dx3 (3)

45 Fitting Analysis of Variation of Rock Mass Pressure withDeformation Fitting is performed on the change of rockmass pressure with settlement and clearance convergenceat the YK214 + 011 section(e representative fitting resultsare selected as shown in Figures 17ndash19 with the fittingcorrelation coefficients in the three functions for eachmonitoring point listed in Tables 4 and 5 and the range ofeach function constant is respectively listed in Tables 3and 6

It can be seen from Tables 3ndash6 that except the leftsidewalls (measurement point No 5) the correlation co-efficients of the fitting results in all points are very high andthe values are all above 07 among which the correlationcoefficient by the logistic function is the highest At the sametime it can be seen that the correlation coefficient obtainedby fitting the logarithmic function is generally low (ere-fore under the condition of two-lane V-class rock mass thelogarithmic function cannot characterize the change of rockmass pressure with deformation In addition although theR2 by the cubic function fitting is very high the fitting curvefinally appears as a rising or falling trend which is notconsistent with the reality so the multiple functions cannot

Upper benchexcavation 32

Middle benchexcavation 25

Lower benchexcavation 18

Construction ofinverted arch 16

Construction ofsecondary lining 9

(a)

Bench excavation33


Constructionof inverted

20


(b)

Figure 15 (a) Proportion of rock mass pressure changes in the arch (b) Proportion of rock mass pressure changes on sidewalls

Y0Y1Y2

Y3Y4Y5

Y6Y7Y8

0 12 24 36 48 60 72 84 96 108 120 132 144 156 168000

005

010

015

020

0255D

Rock

pre

ssur

e (M

Pa)

Proximity to the tunnel face (m)

1D2D 3D

4D

01 23 4

5 67 8

Figure 16 Space curve of rock mass pressure in YK214 + 011 section


0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)

Rock pressureFitting curve

(a)

0 50 100000

002

004

006

008

010

Rock

pre

ssur

e (M

Pa)

Clearance convergence of top bench (mm)


(b)

Figure 18 Logistic function fitting results (a) Fitting results of rock mass pressure and settlement (Y0) (b) Fitting results of rock masspressure and clearance convergence (Y6)

Table 3 Fitting parameter range of rock mass pressure and settlement

Function types Basic form Parameters Value range

Logarithmic function y a minus b ln(x+c)a minus10127sim0045b minus1184sim0005c 2941362sim5151256

Logistic function y ((A1 minus A2)(1 + (xx0)p)) + A2

A1 0003sim0027A2 0046sim0241x0 56413sim82275P 18718sim23257

Multiple functions y A + Bx + Cx2 + Dx3

A minus0007sim0019B minus0002sim0006C minus00002sim00001D minus0002sim0001

0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)


0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)

Clearance convergence of bench (mm)

(b)

Figure 17 Logarithmic function fitting results (a) Fitting results of rock mass pressure and settlement (Y0) (b) Fitting results of rock masspressure and clearance convergence (Y6)


be used to characterize the relationship between pressureand deformation of the rock mass From the range ofconstant terms the value in the logarithmic function isdiscrete while the value in logistic function and multiplefunctions fluctuates little

Considering the above factors the fitting trend of logisticfunction with a higher correlation coefficient is more con-sistent with the measured data and it has the minimumfluctuation of the constant range in characterizing thevariation of rock mass pressure with deformation

0 50 100

00

01

02Ro

ck p

ress

ure (

MPa

)

Settlement (mm)


(a)

0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)



(b)

Figure 19 Multiple function fitting results (a) Fitting results of rock mass pressure and settlement (Y0) (b) Fitting results of rock masspressure and clearance convergence (Y6)

Table 4 Fitting correlation coefficient between rock mass pressure and settlement

Function types Results Y0 Y3 Y4 Y5 Y6Logarithmic function Correlation coefficient R2 0764 0285 0370 0013 0546Logistic function Correlation coefficient R2 0946 0949 0974 0064 0929Multiple functions Correlation coefficient R2 0941 0868 0965 0619 0932

Table 5 Fitting correlation coefficient between rock mass pressure and clearance convergence

Function types Results Y3 Y4 Y5 Y6Logarithmic function Correlation coefficient R2 0259 0534 0071 0713Logistic function Correlation coefficient R2 0948 0975 0103 0968Multiple functions Correlation coefficient R2 0848 0832 0375 0968

Table 6 Fitting parameter range of rock mass pressure and clearance convergence


Logarithmic function y a minus b ln(x+c)a minus52749simminus10081b minus5891simminus1205c 3654005sim7747978




A 0002sim0050B minus0001sim0001C minus000002sim000001D minus00002sim00002


46 Fitting Analysis of the Variation of Rock Mass PressurewithTime Representative fitting curves of the change of rockmass pressure with excavation time at YK214+ 011 section areshown in Figures 20ndash22 the fitting correlation coefficient ofeach point by using three functions is shown in Table 7 andthe range of each function constant is shown in Table 8

It can be seen from Table 7 that the correlation co-efficient between rock mass pressure and excavation timeis high except for the right arch foot (point No 4) Mostcorrelation coefficients are greater than 07 and the

correlation coefficient of the logistic function is thehighest among the three functions At the same time itcan be seen that the fitting curves of multiple functions arestill increasing or decreasing at last which is obviously notconsistent with the actual situation (erefore multiplefunctions cannot be used to characterize the change ofrock mass pressure and excavation time From the valuerange of constant term the value range of the logarithmfunction is larger compared with that of the logisticfunction

0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)

Experience time after excavation (h)


(a)

00

01

02

Rock

pre

ssur

e (M

Pa)

500 1000Experience time after excavation (h)


(b)

Figure 20 Logarithmic function fitting result (a) Logarithmic function fitting result (Y0) (b) Logarithmic function fitting result (Y6)

1 10 100 1000000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)



(b)

Figure 21 Logistic function fitting result (a) Logistic function fitting result (Y0) (b) Logistic function fitting result (Y6)


In general the quality of the fitting function needs toconsider three factors the correlation coefficient R2 thetrend of the fitting curve and the value range of each functionconstant (e logistic function has the highest correlationcoefficient the best fit with data and the range of valuefluctuates little As a result it is recommended to use thelogistic function to characterize the change of rock masspressure with excavation time

47 Fitting Analysis of the Change of Rock Mass Pressure withDistance to Excavation Face (e change of rock masspressure with distance from the tunnel face is fitted andanalyzed (e representative fitting results of each functionare selected as shown in Figures 23ndash25 (e correlationcoefficients obtained by the fitting are recorded in Table 9and the range of the value of each function constant item isrecorded in Table 10

Table 7 Correlation coefficient between rock mass pressure and excavation time


Table 8 Range of parameters for rock mass pressure and excavation time


Logarithmic function y a minus b ln(x+c)a minus52439sim0017b minus5248simminus0084c minus24sim119254





0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)

Experience time after excavation (h)Rock pressureFitting curve

(b)

Figure 22 Multiple function fitting result (a) Multiple function fitting result (Y0) (b) Multiple function fitting result (Y6)


It can be seen from Table 9 that the correlation coeffi-cient between rock mass pressure and distance from exca-vation face is high except for the right arch foot (point No4) Most correlation coefficient are greater than 07 amongthem the logistic function has the highest correlation co-efficient At the same time it can be seen that the fittingcurve obtained by multiple functions is inconsistent with themeasured data(erefore multiple functions cannot be usedto characterize the spatial variation of rock mass pressureFrom the value range of each function constant term it can

be concluded that the value range of the logarithm functionis wide and the value range of the logistic function is rel-atively concentrated

Considering above factors when the logistic functionis used to characterize the change of the rock masspressure and the distance from the tunnel face thecorrelation coefficient is higher the trend of the fittingcurve is more consistent with the actual situation andthe range of each constant term is easier to bedetermined

1 10 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Distance from the tunnel face (m)


(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)


0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)



5 Conclusion

In this paper based on the measured rock mass pressure atthe Mingyazi tunnel the change of rock mass pressure in theconstruction process with tunnel deformation constructionprocess excavation time and distance from the tunnel faceis analyzed (e following conclusions are obtained

(1) (e increase of rock mass pressure and deformationis inconsistent When the clearance convergence andsettlement experience a rapid growth the rock masspressure appears to increase first and then decrease(is is caused by the insufficient bearing capacity of

the rock mass in the arch foot of the supportingstructure after the excavation of the upper benchwhich leads to a settlement of supporting structureand surrounding rock

(2) During construction the rockmass pressure is mostly005sim023MPa and changed slowly After each pro-cess the rock mass pressure adjustment time is longand reaches stable about 15 days after the secondarylining installation It takes 65 to 70 days for the tunnelto stabilize after excavation and support

(3) In the process of each construction stage the changeproportion of rock mass pressure is relatively

Table 10 Range of fitting parameters of rock mass pressure and distance from the tunnel face


Logarithmic function y a minus b ln(x+c)a minus31034sim0019b minus4255simminus0001c 1465809sim4976583





Table 9 Fitting correlation coefficient between rock mass pressure and distance from the tunnel face


0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)



uniform When the supporting structure gets a fullring closure the proportion of the rock mass pres-sure change value at each part accounted for 65 ofthe final monitoring value

(4) Under construction the space effect of the tunnelface is very significant In the process of tunnelexcavation due to the constraints of the excavationsurface the surrounding rock cannot immediatelyrelease all the instantaneous elastic displacementwhich is called the ldquospace effectrdquo of the excavationsurface When the test section is within two times ofthe diameter of the tunnel the rock mass pressure issignificantly affected by the excavation of the tunnelface (e spatial impact range is within three timesthe diameter of the tunnel (37m) and the rheo-logical properties of the rock mass dominate thechanges afterwards In view of the influence of rockrheological properties on rock pressure further re-search is still needed

(5) (e logarithmic function logistic function andmultiple functions are used to fit and analyze therelationship between rock mass pressure deforma-tion excavation time and distance from the tunnelface It is found that the R2 of the logistic function isgenerally greater than 09 which shows that thefitting curve is the most consistent with the actualdata and has a better fitting effect (erefore it isproposed to use the logistic function to express andpredict the change of rock mass pressure during theconstruction of the phyllite stratum tunnel so as toensure the safe construction of the tunnel

Data Availability

(e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

(e authors declare no conflicts of interest

Acknowledgments

(is research was funded by the National Key RampD Programof China (Grant no 2018YFB1600100) the Key Project ofNational Natural Science Foundation of China (Grant no41831286) the Youth Project of National Natural ScienceFoundation of China (Grant nos 51908052 and 51808049)Natural Science Foundation of Shaanxi Province (Grant no211421190347) and the Fundamental Research Funds forthe Central Universities of Ministry of Education of China(Grant no 300102210216) (ese supports are gratefullyacknowledged

References

[1] J X Chen W W Liu L J Chen et al ldquoFailure mechanismsand modes of tunnels in monoclinic and soft-hard

interbedded rocks a case studyrdquo KSCE Journal of Civil En-gineering vol 24 no 4 2020

[2] W W Liu J X Chen L J Chen Y B Luo Z Shi andYF Wu ldquoNonlinear deformation behaviors and a new ap-proach for the classification and prediction of large defor-mation in tunnel construction stage a case studyrdquo EuropeanJournal of Environmental and Civil Engineering 2020

[3] J L Qiu Y Q Lu J X Lai C X Guo and K Wang ldquoFailurebehavior investigation of loess metro tunnel under local-high-pressure water environmentrdquo Engineering Failure Analysisvol 115 Article ID 104631 2020

[4] G Galli A Grimaldi and A Leonardi ldquo(ree-dimensionalmodelling of tunnel excavation and liningrdquo Computers andGeotechnics vol 31 no 3 pp 171ndash183 2004

[5] H Duddeck ldquoApplication of numerical analyses for tun-nellingrdquo International Journal for Numerical and AnalyticalMethods in Geomechanics vol 15 no 4 pp 223ndash239 1991

[6] Y Luo J Chen P Huang M Tang X Qiao and Q LiuldquoDeformation and mechanical model of temporary supportsidewall in tunnel cutting partial sectionrdquo Tunnelling andUnderground Space Technology vol 61 pp 40ndash49 2017

[7] V Kontogianni P Psimoulis and S Stiros ldquoWhat is thecontribution of time-dependent deformation in tunnel con-vergencerdquo Engineering Geology vol 82 no 4 pp 264ndash2672006

[8] C Zhao A Alimardani Lavasan T Barciaga C KamperP Mark and T Schanz ldquoPrediction of tunnel lining forcesand deformations using analytical and numerical solutionsrdquoTunnelling and Underground Space Technology vol 64pp 164ndash176 2017

[9] T D Y F Mark M Marence A E Mynett and A J SchleissldquoPressure tunnels in non-uniform in situ stress conditionsrdquoTunnelling and Underground Space Technology vol 42pp 227ndash236 2014

[10] J Litwiniszyn ldquoApplication of the equation of stochasticprocesses to mechanics of loose bodiesrdquo Archives of Me-chanics vol 8 no 4 pp 393ndash411 1956

[11] J X Chen Z L Xu Y B Luo J K Song W W Liu andF F Dong ldquoApplication of the upper-bench CD method insuper large-span and shallow tunnel a case study of LetuanTunnelrdquo Advances in Civil Engineering vol 2020 p 16Article ID 8826232 2020

[12] Y B Luo Z Shi J X Chen et al ldquoStudy of deformationbehaviors and mechanical properties of central diaphragm ina large-span loess tunnel by the upper bench CD methodrdquoAdvances in Civil Engineering vol 2020 p 16 Article ID8887040 2020

[13] M Panet ldquoTime-dependent deformations in undergroundworksrdquo in Proceedings of the 4th ISRM Congress MontreuxSwitzerland September 1979

[14] R Guo Y Fang and C He ldquoStudy on the correlation betweenstress release and displacement release during tunnel exca-vationrdquo Journal of Railway Engineering vol 27 no 9pp 46ndash50 2010

[15] S C Li Y Zhao and L P Li ldquoStudy of construction sectioncomprehensive load releasing process of ultra-large sectionrailway tunnelrdquo Rock and Soil Mechanics vol 32 no 9pp 2845ndash2851 2011

[16] M Lei L Peng and C Shi ldquoModel test to investigate thefailure mechanisms and lining stress characteristics of shallowburied tunnels under unsymmetrical loadingrdquo Tunnelling andUnderground Space Technology vol 46 pp 64ndash75 2015

[17] F Huang C Wu B-A Jang Y Hong N Guo and W GuoldquoInstability mechanism of shallow tunnel in soft rock


subjected to surcharge loadsrdquo Tunnelling and UndergroundSpace Technology vol 99 Article ID 103350 2020

[18] D Y Li Z X Xu and L J Wang ldquoNumerical simulationanalysis of the combined system of the initial support of theunderground tunnelrdquo Railway Engineering vol 34 no 5pp 34ndash37 2007

[19] E Eberhardt ldquoNumerical modelling of three-dimension stressrotation ahead of an advancing tunnel facerdquo InternationalJournal of Rock Mechanics and Mining Sciences vol 38 no 4pp 499ndash518 2001

[20] J Chen Y Luo Y Li P Zhao D Xu and Q Wang ldquo(echange of rock mass pressure of Lianchengshan tunnelrdquoEnvironmental Earth Sciences vol 79 no 9 2020

[21] J C Hu F Y Sun Y Li L Cui and M J Ji ldquoOn-sitemonitoring and comparative analysis about surrounding rockpressure variation with time in unsymmetrical loading tunnelrdquoEarth and Environmental Science vol 295 pp 42ndash51 2019

[22] G Walton D Delaloye and M S Diederichs ldquoDevelopmentof an elliptical fitting algorithm to improve change detectioncapabilities with applications for deformation monitoring incircular tunnels and shaftsrdquo Tunnelling and UndergroundSpace Technology vol 43 pp 336ndash349 2014

[23] V A Kontogianni and S C Stiros ldquoInduced deformationduring tunnel excavation evidence from geodetic monitor-ingrdquo Engineering Geology vol 79 no 1-2 pp 115ndash126 2005

[24] D K W Tang K M Lee and C W W Ng ldquoStress pathsaround a 3-D numerically simulated NATM tunnel in stiffclayrdquo in Proceedings of the International Symposium onGeotechnical Aspects of Underground Construction in SoftGround (IS-Tokyo 99) Tokyo Japan July 2000

[25] L H I Meyer D Stead and J S Coggan ldquo(ree dimensionalmodelling of the effects of high horizontal stress on under-ground excavation stabilityrdquo in Proceedings of the Interna-tional Society for Rock Mechanics and Rock Engineeringpp 25ndash28 Paris France August 1999

[26] R E Ranken and J Ghaboussi ldquoTunnel design considerationsanalysis of stresses and deformations around advancingtunnelsrdquo Final Report to Federal Railroad Administration(Report No FRAOR amp D 75ndash84) Department of Trans-portation Washington DC USA 1975

[27] G Hocking ldquo(ree-dimensional elastic stress distributionaround the flat end of a cylindrical cavityrdquo InternationalJournal of Rock Mechanics and Mining Sciences amp Geo-mechanics Abstracts vol 13 no 12 pp 331ndash337 1976

[28] Q S Xu Y Z Niu and Q Z Li ldquoStudy on constructionmechanics of eccentric tunnel method of double-arch tunnelsection of Shenzhen metro line 8rdquo Highway vol 3pp 256ndash259 2017

[29] JTGTF60-2009 ldquoTechnical Specifications for HighwayTunnel Constructionrdquo China Communications Press BeijingChina 2009


method of model test to systematically study the change lawsand distribution forms of structural stress and rock masspressure of shallow buried tunnels (e results show that therockmass pressure and structural stress constantly change inthe process of tunnel excavation and the stress release nearthe excavation face is large showing unsymmetrical pressurecharacteristics and time-space effect [16] Huang et alstudied the failure mechanism of soft rock tunnel undersurcharge through the large-scale model test and found thatthe rock mass pressure is mainly concentrated on the roof ofthe tunnel rather than the sidewall [17] Numerical mod-elling is also widely used to simulate the change of the rockmass pressure together with the back analysis Li et almodeled the stress changes during the construction of asubway tunnel and results showed that the rock masspressure near excavation changed significantly until the ringclosure was reached [18] Mark et al used a finite-elementmodel (FEM) to study the distribution of stress strain anddeformation during tunnel excavation And the bearingcapacity of pressure tunnels was determined by the super-position principle [9] Eberhardt researched the near-fieldstress path in the excavation process with a detailed three-dimensional finite-element model (e results demonstratethat the spatial and temporal evolution of the three-di-mensional stress field includes a series of changes ofdeviatoric stress as well as principal stress axis [19] Chenet al studied the change of rock mass pressure during theconstruction of soft rock tunnel through the combination offield monitoring and numerical simulation and found thatthe surrounding rock pressure was stable 65 to 70 days afterthe completion of support structure [20] (e correctness ofthe analytical solution and model test is verified by nu-merical simulation but it is still different from the actualsituation in the field(erefore fieldmonitoring has a strongpractical significance in the process of tunnel research

On-site monitoring plays an important role in theanalysis of rock mass pressure during tunnel constructionHu et al found that the horizontal stress of the bias tunnelwas over released and the measured pressure value of sidewalls was much larger than the calculated pressure value bycomparing the on-site monitoring data with the theoreticalcalculation results [21] Walton et al used LiDAR scan datafor tunnel section analysis and back-calculation A newellipse fitting data analysis method is proposed which can beused to analyze the rock mass pressure distribution of thetunnel section [22] Kontogianni and Stiros analyzed a largenumber of records obtained by electronic theodolite intunnels It proved that the deformation in tunnels would beaffected by the stress release of adjacent parts of the rockmass [23]

In the past a large number of researchers have obtainedthe law that the rock mass pressure decreases with the in-crease of surrounding rock deformation through numericalsimulation and theoretical calculation [24ndash28] (is is dif-ferent from the change rule that the rock mass pressureincreases first and then decreases when the clearance con-vergence and settlement increase rapidly which is moni-toring under the special geological conditions in this paper(erefore further research is needed to provide a theoretical

basis for the design and construction of the tunnel Based onthe monitoring of the Mingyazi tunnel this study analyzesthe variation of rock mass pressure with the deformationtime and distance from excavation face during the con-struction process of the phyllite tunnel and summarizes achanging pattern

2 Project Overview

(e Mingyazi tunnel is located in Shaanxi province It is afour-lane two-tunnel expressway project (e left line tunnelis 4949m and the right line tunnel is 4985m It is anextralong tunnel with a maximum buried depth of 320m

(e monitoring measurement section is selectedaccording to the field conditions (e right line has 9 de-formation monitoring sections including 1 stress moni-toring section and the station number of the stressmonitoring section is YK214 + 011 (hereinafter referred to as011 section) (e main lithology of the monitoring section isgray-black carbon phyllite with low stability and strengthwhich is easy to produce creep and be soften in water Itbelongs to the grade V weak rock mass segment according toldquoTechnical Specifications for Highway Tunnel Constructionrdquo(JTGTF60-2009) [29] (e surrounding rock conditions ofsection 011 are shown in Figure 1

Tunnel construction adopts three-bench and seven-stepconstruction method and its construction sequence isshown in Figure 2 (e construction sequence is to excavatethe arc heading (1) left and right sides of the middle bench(2 3) left and right sides of the lower bench (4 5) and finallyexcavate the three parts of reserved core soil (6ndash1 6ndash2 6ndash3)

(e tunnel is supported by a composite lining Groutedpipe spiling is used for presupport the usually used rockbolts are not used and the feet-lock anchor pipe is installed(e support parameters are shown in Figure 3

3 In Situ Monitoring

According to the requirements of ldquoTechnical Specificationsfor Highway Tunnel Constructionrdquo (JTGTF60-2009)[29] the monitoring contents and methods of the Min-gyazi tunnel are proposed based on its constructionmethods and geological conditions In the monitoring ofcrown settlement and clearance convergence the non-contact measurement method is used to improve themeasurement precision and complete the collection ofmonitoring data in the field Monitoring items instru-ments and sensors are summarized in Table 1 (e de-formation of the monitoring section the layout of themeasuring points and the numbers of the survey pointsare shown in Figures 4 and 5

4 Analysis of Monitoring Results

41 Variation of Rock Mass Pressure and Deformation withTime (e relation between the rock mass pressure andsettlement of the YK214 + 011 section is shown inFigures 6ndash10 (e relation between rock mass pressure andclearance convergence is shown in Figures 11 and 12 Yx




Rock mass


1

1 16-1 3

2

4

56-2

6-3







Pipe L = 400


Φ22 feet-lock













Arch vault






1

3

2

87

4

5 6

0

Pressure cell


30deg

30deg30deg

24deg


424 51 58 515 522 529 65 612 619000

001

002

003

004

005

006


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

120

140

160

Settl

emen

t (m

m)

Y3Settlement


424 51 58 515 522 529 65 612 619000

005

010

015

020

Y0Settlement


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)






428 55 512 519 526 62 69 616000

002

004

006

008

010


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)

Y5Settlement


428 55 512 519 526 62 69 616000

005

010

015

020

025


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)

Y6Settlement


421

426 5

1

56

511

516

521

526

531 6

5

610

615

620

000

005

010

015

020

025

Y0Y1

Y3Top heading


Rock

mas

s pre

ssur

e (M

Pa)

0

20

40

60

80

100

120

Clea

ranc

e con

verg

ence

(mm

)

Benchexcavation




430 55 510 515 520 525 530 64 69 614 619000002004006008010012014016018020022024

Y5Y6Bench


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

50

100

150

200

250

Clea

ranc

e con

verg

ence

(mm

)


424 51 58 515 522 529 65 612 619000

002

004

006

008

010

012

014

016


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

120

140

Settl

emen

t (m

m)

Y4Settlement









Monitoringpositions






Ratio()

Rock masspressure

Ratio()

Rock masspressure

Ratio()

Rock masspressure

Ratio()


000005010015020025

Rock

pre

ssur

e (M

Pa)


Y0Y1Y2

Y3Y4Y5

Y6Y7Y8

Benchexcavation


of invert


429 5

6

513

520

527 6

3

610

617

624 7

1

78

715

722


1

3

2

87

4

5 6

0

0206

0022

0089

0223

Damaged

0116

0052

0093

0042

Unit MPa






y A1 minus A2

1 + xx0( 1113857p + A2 (2)

y A + Bx + Cx2

+ Dx3 (3)








(a)

Bench excavation33



20


(b)


Y0Y1Y2

Y3Y4Y5

Y6Y7Y8

0 12 24 36 48 60 72 84 96 108 120 132 144 156 168000

005

010

015

020

0255D

Rock

pre

ssur

e (M

Pa)


1D2D 3D

4D

01 23 4

5 67 8



0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)

0 50 100000

002

004

006

008

010

Rock

pre

ssur

e (M

Pa)



(b)









0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)


0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)


(b)





0 50 100

00

01

02Ro

ck p

ress

ure (

MPa

)

Settlement (mm)


(a)

0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)



(b)

















0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

00

01

02

Rock

pre

ssur

e (M

Pa)



(b)


1 10 100 1000000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)



(b)














0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)


(b)






1 10 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)


0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)



5 Conclusion















0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)






Data Availability




Acknowledgments


References




































Rock mass


1

1 16-1 3

2

4

56-2

6-3







Pipe L = 400


Φ22 feet-lock













Arch vault






1

3

2

87

4

5 6

0

Pressure cell


30deg

30deg30deg

24deg


424 51 58 515 522 529 65 612 619000

001

002

003

004

005

006


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

120

140

160

Settl

emen

t (m

m)

Y3Settlement


424 51 58 515 522 529 65 612 619000

005

010

015

020

Y0Settlement


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)






428 55 512 519 526 62 69 616000

002

004

006

008

010


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)

Y5Settlement


428 55 512 519 526 62 69 616000

005

010

015

020

025


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)

Y6Settlement


421

426 5

1

56

511

516

521

526

531 6

5

610

615

620

000

005

010

015

020

025

Y0Y1

Y3Top heading


Rock

mas

s pre

ssur

e (M

Pa)

0

20

40

60

80

100

120

Clea

ranc

e con

verg

ence

(mm

)

Benchexcavation




430 55 510 515 520 525 530 64 69 614 619000002004006008010012014016018020022024

Y5Y6Bench


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

50

100

150

200

250

Clea

ranc

e con

verg

ence

(mm

)


424 51 58 515 522 529 65 612 619000

002

004

006

008

010

012

014

016


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

120

140

Settl

emen

t (m

m)

Y4Settlement









Monitoringpositions






Ratio()

Rock masspressure

Ratio()

Rock masspressure

Ratio()

Rock masspressure

Ratio()


000005010015020025

Rock

pre

ssur

e (M

Pa)


Y0Y1Y2

Y3Y4Y5

Y6Y7Y8

Benchexcavation


of invert


429 5

6

513

520

527 6

3

610

617

624 7

1

78

715

722


1

3

2

87

4

5 6

0

0206

0022

0089

0223

Damaged

0116

0052

0093

0042

Unit MPa






y A1 minus A2

1 + xx0( 1113857p + A2 (2)

y A + Bx + Cx2

+ Dx3 (3)








(a)

Bench excavation33



20


(b)


Y0Y1Y2

Y3Y4Y5

Y6Y7Y8

0 12 24 36 48 60 72 84 96 108 120 132 144 156 168000

005

010

015

020

0255D

Rock

pre

ssur

e (M

Pa)


1D2D 3D

4D

01 23 4

5 67 8



0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)

0 50 100000

002

004

006

008

010

Rock

pre

ssur

e (M

Pa)



(b)









0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)


0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)


(b)





0 50 100

00

01

02Ro

ck p

ress

ure (

MPa

)

Settlement (mm)


(a)

0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)



(b)

















0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

00

01

02

Rock

pre

ssur

e (M

Pa)



(b)


1 10 100 1000000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)



(b)














0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)


(b)






1 10 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)


0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)



5 Conclusion















0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)






Data Availability




Acknowledgments


References












































Arch vault






1

3

2

87

4

5 6

0

Pressure cell


30deg

30deg30deg

24deg


424 51 58 515 522 529 65 612 619000

001

002

003

004

005

006


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

120

140

160

Settl

emen

t (m

m)

Y3Settlement


424 51 58 515 522 529 65 612 619000

005

010

015

020

Y0Settlement


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)






428 55 512 519 526 62 69 616000

002

004

006

008

010


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)

Y5Settlement


428 55 512 519 526 62 69 616000

005

010

015

020

025


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)

Y6Settlement


421

426 5

1

56

511

516

521

526

531 6

5

610

615

620

000

005

010

015

020

025

Y0Y1

Y3Top heading


Rock

mas

s pre

ssur

e (M

Pa)

0

20

40

60

80

100

120

Clea

ranc

e con

verg

ence

(mm

)

Benchexcavation




430 55 510 515 520 525 530 64 69 614 619000002004006008010012014016018020022024

Y5Y6Bench


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

50

100

150

200

250

Clea

ranc

e con

verg

ence

(mm

)


424 51 58 515 522 529 65 612 619000

002

004

006

008

010

012

014

016


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

120

140

Settl

emen

t (m

m)

Y4Settlement









Monitoringpositions






Ratio()

Rock masspressure

Ratio()

Rock masspressure

Ratio()

Rock masspressure

Ratio()


000005010015020025

Rock

pre

ssur

e (M

Pa)


Y0Y1Y2

Y3Y4Y5

Y6Y7Y8

Benchexcavation


of invert


429 5

6

513

520

527 6

3

610

617

624 7

1

78

715

722


1

3

2

87

4

5 6

0

0206

0022

0089

0223

Damaged

0116

0052

0093

0042

Unit MPa






y A1 minus A2

1 + xx0( 1113857p + A2 (2)

y A + Bx + Cx2

+ Dx3 (3)








(a)

Bench excavation33



20


(b)


Y0Y1Y2

Y3Y4Y5

Y6Y7Y8

0 12 24 36 48 60 72 84 96 108 120 132 144 156 168000

005

010

015

020

0255D

Rock

pre

ssur

e (M

Pa)


1D2D 3D

4D

01 23 4

5 67 8



0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)

0 50 100000

002

004

006

008

010

Rock

pre

ssur

e (M

Pa)



(b)









0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)


0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)


(b)





0 50 100

00

01

02Ro

ck p

ress

ure (

MPa

)

Settlement (mm)


(a)

0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)



(b)

















0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

00

01

02

Rock

pre

ssur

e (M

Pa)



(b)


1 10 100 1000000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)



(b)














0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)


(b)






1 10 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)


0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)



5 Conclusion















0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)






Data Availability




Acknowledgments


References





































428 55 512 519 526 62 69 616000

002

004

006

008

010


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)

Y5Settlement


428 55 512 519 526 62 69 616000

005

010

015

020

025


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

Settl

emen

t (m

m)

Y6Settlement


421

426 5

1

56

511

516

521

526

531 6

5

610

615

620

000

005

010

015

020

025

Y0Y1

Y3Top heading


Rock

mas

s pre

ssur

e (M

Pa)

0

20

40

60

80

100

120

Clea

ranc

e con

verg

ence

(mm

)

Benchexcavation




430 55 510 515 520 525 530 64 69 614 619000002004006008010012014016018020022024

Y5Y6Bench


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

50

100

150

200

250

Clea

ranc

e con

verg

ence

(mm

)


424 51 58 515 522 529 65 612 619000

002

004

006

008

010

012

014

016


Rock

mas

s pre

ssur

e (M

Pa)

Benchexcavation



0

20

40

60

80

100

120

140

Settl

emen

t (m

m)

Y4Settlement









Monitoringpositions






Ratio()

Rock masspressure

Ratio()

Rock masspressure

Ratio()

Rock masspressure

Ratio()


000005010015020025

Rock

pre

ssur

e (M

Pa)


Y0Y1Y2

Y3Y4Y5

Y6Y7Y8

Benchexcavation


of invert


429 5

6

513

520

527 6

3

610

617

624 7

1

78

715

722


1

3

2

87

4

5 6

0

0206

0022

0089

0223

Damaged

0116

0052

0093

0042

Unit MPa






y A1 minus A2

1 + xx0( 1113857p + A2 (2)

y A + Bx + Cx2

+ Dx3 (3)








(a)

Bench excavation33



20


(b)


Y0Y1Y2

Y3Y4Y5

Y6Y7Y8

0 12 24 36 48 60 72 84 96 108 120 132 144 156 168000

005

010

015

020

0255D

Rock

pre

ssur

e (M

Pa)


1D2D 3D

4D

01 23 4

5 67 8



0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)

0 50 100000

002

004

006

008

010

Rock

pre

ssur

e (M

Pa)



(b)









0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)


0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)


(b)





0 50 100

00

01

02Ro

ck p

ress

ure (

MPa

)

Settlement (mm)


(a)

0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)



(b)

















0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

00

01

02

Rock

pre

ssur

e (M

Pa)



(b)


1 10 100 1000000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)



(b)














0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)


(b)






1 10 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)


0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)



5 Conclusion















0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)






Data Availability




Acknowledgments


References








































Monitoringpositions






Ratio()

Rock masspressure

Ratio()

Rock masspressure

Ratio()

Rock masspressure

Ratio()


000005010015020025

Rock

pre

ssur

e (M

Pa)


Y0Y1Y2

Y3Y4Y5

Y6Y7Y8

Benchexcavation


of invert


429 5

6

513

520

527 6

3

610

617

624 7

1

78

715

722


1

3

2

87

4

5 6

0

0206

0022

0089

0223

Damaged

0116

0052

0093

0042

Unit MPa






y A1 minus A2

1 + xx0( 1113857p + A2 (2)

y A + Bx + Cx2

+ Dx3 (3)








(a)

Bench excavation33



20


(b)


Y0Y1Y2

Y3Y4Y5

Y6Y7Y8

0 12 24 36 48 60 72 84 96 108 120 132 144 156 168000

005

010

015

020

0255D

Rock

pre

ssur

e (M

Pa)


1D2D 3D

4D

01 23 4

5 67 8



0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)

0 50 100000

002

004

006

008

010

Rock

pre

ssur

e (M

Pa)



(b)









0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)


0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)


(b)





0 50 100

00

01

02Ro

ck p

ress

ure (

MPa

)

Settlement (mm)


(a)

0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)



(b)

















0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

00

01

02

Rock

pre

ssur

e (M

Pa)



(b)


1 10 100 1000000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)



(b)














0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)


(b)






1 10 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)


0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)



5 Conclusion















0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)






Data Availability




Acknowledgments


References





































y A1 minus A2

1 + xx0( 1113857p + A2 (2)

y A + Bx + Cx2

+ Dx3 (3)








(a)

Bench excavation33



20


(b)


Y0Y1Y2

Y3Y4Y5

Y6Y7Y8

0 12 24 36 48 60 72 84 96 108 120 132 144 156 168000

005

010

015

020

0255D

Rock

pre

ssur

e (M

Pa)


1D2D 3D

4D

01 23 4

5 67 8



0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)

0 50 100000

002

004

006

008

010

Rock

pre

ssur

e (M

Pa)



(b)









0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)


0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)


(b)





0 50 100

00

01

02Ro

ck p

ress

ure (

MPa

)

Settlement (mm)


(a)

0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)



(b)

















0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

00

01

02

Rock

pre

ssur

e (M

Pa)



(b)


1 10 100 1000000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)



(b)














0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)


(b)






1 10 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)


0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)



5 Conclusion















0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)






Data Availability




Acknowledgments


References


































0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)

0 50 100000

002

004

006

008

010

Rock

pre

ssur

e (M

Pa)



(b)









0 50 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)

Settlement (mm)


(a)


0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)


(b)





0 50 100

00

01

02Ro

ck p

ress

ure (

MPa

)

Settlement (mm)


(a)

0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)



(b)

















0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

00

01

02

Rock

pre

ssur

e (M

Pa)



(b)


1 10 100 1000000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)



(b)














0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)


(b)






1 10 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)


0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)



5 Conclusion















0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)






Data Availability




Acknowledgments


References




































0 50 100

00

01

02Ro

ck p

ress

ure (

MPa

)

Settlement (mm)


(a)

0 100 20000

01

02

Rock

pre

ssur

e (M

Pa)



(b)

















0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

00

01

02

Rock

pre

ssur

e (M

Pa)



(b)


1 10 100 1000000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)



(b)














0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)


(b)






1 10 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)


0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)



5 Conclusion















0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)






Data Availability




Acknowledgments


References





































0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

00

01

02

Rock

pre

ssur

e (M

Pa)



(b)


1 10 100 1000000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)



(b)














0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)


(b)






1 10 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)


0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)



5 Conclusion















0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)






Data Availability




Acknowledgments


References













































0 1000 2000

00

01

02Ro

ck p

ress

ure (

MPa

)



(a)

500 100000

01

02

Rock

pre

ssur

e (M

Pa)


(b)






1 10 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)


0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)



5 Conclusion















0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)






Data Availability




Acknowledgments


References





































1 10 100000

005

010

015

020

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)


0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)



5 Conclusion















0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)






Data Availability




Acknowledgments


References


































5 Conclusion















0 50 100 150

00

01

02

Rock

pre

ssur

e (M

Pa)



(a)

20 40 60 8000

01

02

Rock

pre

ssur

e (M

Pa)



(b)






Data Availability




Acknowledgments


References





































Data Availability




Acknowledgments


References


































VariationofRockMassPressureduringTunnelConstructionin...

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Transcript of VariationofRockMassPressureduringTunnelConstructionin...