PROPOSED CONSTRUCTION OF RESIDNTIAL APARTMENT AT … · Based on soil strata open shallow...

PROPOSED CONSTRUCTION OF RESIDNTIAL APARTMENT

AT BAJANAI KOIL STREET,SELAIYUR

Report on Geotechnical Investigation

Client: M/s. Alankar Construction,

Chennai.

MARS SYNERGY GEO TECH Pvt Ltd

ISO 9001: 2008 Company # 30/25 Drowpathy Amman Koil 1

st Street

Velachery, Chennai-600 042.

Ph : (044) –22452845, Tele Fax: 2245 0281 Mail : [email protected], [email protected],

Web: www.msgeotech.com

Project No: MSGTPL/SI-2746/14-15 Aug-2014.

Geo-Technical Investigation Report

Project No: MSGTPL/SI-2746/14-15 Aug-2014

Proposed Construction of Residential Apartment at Selaiyur

TABLE OF CONTENTS

1.0 INTRODUCTION……………………………………………………………………. 1

1.1 DESCRIPTION OF STRUCTURE………………………………………………… 1

1.2 SOIL INVESTIGATION PROGRAMME …………………………………………. 1

1.3 FIELD SAMPLING……………………………………………….………………… 2

1.4 LABORATORY TESTS…………………………………………………………… 2

1.5 SOIL PROFILE………………………………………………………………………. 2

1.6 GROUND WATER TABLE……………………………………………………….. 3

1.7 DISCUSSION ON FOUNDATION…………………………………………………. 3

1.8 RECOMMENDATIONS……………………………………………………………. 3

2.0 SAFE BEARING CAPACITY CALCULATIONS................................................ 4

3.0 SITE PLAN –MSGTPL/SI-2746……………………………………………………. 5

4.0 BORE-LOGS………………………………………………………………………… . 6

5.0 TEST RESULTS…………………………………………………………………….. 7

6.0 NATURAL MOISTURE CONTENT……………………………………………….. 8

7.0 SPECIFIC GRAVITY…………………………………………………………………. 9

8.0 GRAIN SIZE ANALYSIS…………………………………………………………….. 10



1


REPORT ON SUB SOIL INVESTIGATION AND RECOMMENDATION FOR THE

FOUNDATION OF THE PROPOSED CONSTRUCTION OF RESIDENTIAL

APARTMENT AT SELAIYUR.

1.0 INTRODUCTION

M/s. Alankar Construction, Chennai are planning to construct the residential apartment

at No.27, Bajanai koil Street, Bharathi Nagar, Selaiyur, Chennai-600 073, Tamilnadu,

India. M/s. Mars Synergy Geotech Pvt Ltd, Chennai has carried out this investigation

and completed the field work on 15th Aug 2014 according to the instructions from the

owner of the project.

The scope of work includes the following:

� Making one number of Standard Soil Investigation bore-hole

� Collecting soil samples at regular depth intervals

� Conducting SPTs at every 1.0m/1.50m depth intervals

� Conducting laboratory tests on samples collected

� Submitting report with laboratory test results and recommendation for

foundations.

1.1 DESCRIPTION OF STRUCTURE

The proposed structure is residential apartment (Stilt+2). The exact details of columns

are not available at the time of preparation of this report. Assuming an approximate

column spacing of 4 to 5 m c/c considering this the central column load works about 60

to 75 tons for proposed building. These loads are assumed for the purpose of foundation

only and for the structural design, exact loads are to be estimated based on a suitable

structural analysis.

1.2 SOIL INVESTIGATION

The field investigation works were carried out using 1 set of Rotary mechanical drilling

Rig. The following activities, carried out in chronological sequence, comprised the

fieldwork for the project

• Mobilisation of rotary drill rig, water pump, testing tools and accessories.

• Collection of disturbed samples of non-cohesive soils.

• Sampling and logging of the boreholes. Packing, labeling and dispatching the

samples to laboratory.

• Field investigation, tests and laboratory tests conducted as per IS-1892 and IS -2720



2


1.3 FIELD SAMPLING

One number of standard soil investigation borehole of 100mm diameter was made at the

location shown in the figure, MSGTPL/SI-2746 enclosed. Investigations were conducted

5.0m from existing ground level where SPT is more than 50blows. SPTs were conducted

at every 1.0m depth intervals and samples were collected for identification and testing.

1.4 LABORATORY TESTS

The laboratory-testing scheme is so designed to obtain the design parameters for the

foundations. The following parameters are evaluated:

� Type of soil and it's gradation properties

� Specific Gravity

� Natural Moisture Content (NMC)

� Sieve analysis on the coarse grained soil fraction

All the test results are presented in the tabular forms. Comprehensive field information

along with SPT values is presented on separate sheet.

1.5 SOIL PROFILE:

Based on visual identification of soil samples and test results (of both field and

laboratory tests), the soil profile arrived. Subsoil is made-up of four distinctive layers

there are

(i) Medium dense SAND up to -1.0m with SPT’s N=12

(ii) Very dense moorum -1.0m to -2.0m with SPT’s N=>50

(iii) Soft disintegrated Rock -2.0m to -4.0m with SPT’s N=>100

(iv) Fractured Hard Rock -4.0m to -5.0 with core recovery is 5%

The soil profile details are presented in the bore-chart.

1.6 GROUND WATER TABLE

At the time of soil investigation (15/08/2014), the ground water table was (-)3.20m

encountered within the drilled depth



3


1.7 DISCUSSION ON FOUNDATION

From the sub soil profile and laboratory test data, it can be seen that the soil is medium

dense sand up to -1.0m followed by very dense moorum up to -2.0m followed by soft

disintegrated rock up to -4.0m below this layer 1.0m thick fractured hard rock up to -5.0m

from exciting G.L

Based on soil strata open shallow foundation can be adopted at -2.0m level from existing

ground level.

1.8 RECOMMENDATIONS

Excavate up to -2.0m, after excavation proper compaction to be done .

Open shallow foundation in the form of isolated/strip raft located at a depth of 2.0m

below the G.L

The Safe bearing capacity can be taken of soil at 2.0m below G.L can be taken as

25T/sq.m.

These footing should rest on 100mm thick of 1:3:6 mat.

Columns shall be tied in both directions at plinth level.

All foundation works should be done in dry conditions only.

Note: This recommendation has been given on the assumed loads. The structural engineer

can modify based on structural analysis on actual size of the building and column details.



4


2.0 DETERMINATION OF BEARING CAPACITY OF SHALLOW FOUNDATIONS [Based On IS: 6403-1981]

Type of Foundation: Isolated footing Width of footing: 2mx2m (For Calculation Purpose)

Depth of Foundation: 2.0m

Existing Ground level: 0.00M

Ground Water Table level: -0.00M (Due to Heavy Rain Temporary)

Bulk Density (W) of Soil above Footing Base: 1.80

Submerged Density (W') of Soil above Footing Base: 0.80T/Cu.M.

Bulk Density (W) of Soil below Footing Base: 1.80T/Cu.M.

Factor of Safety 3.0

Shape factor Depth Factor Inclination Factor Sq = 1.200 Dq = 1.18 Iq = 1.000 Sg = 0.600 Dg = 1.18 Ig = 1.000 Water Table Correction Factor w’ = 0.50

Effective surcharge at base level q = 1.60T/Sq.M.

Ultimate Net B.C. = Qult_n = q*(Nq-1)*Sq*Dq*Iq + 0.5*B*W*Ng*Sg*Dg*Ig*W'

Angle of Internal Friction (phai): 330

Bearing Capacity Factors Nq = 27.34, Ng =37.78

Thus Qult_n =83.75 T/Sq.M.

Allowable Bearing Capacity (Qall) = 83.75/3.0= 27.91 T/Sq.M. Say 25 T/m2

Settlement Calculations as per IS-8009-(Part1) 1998

S= Sc+Si

Sc≈5mm

=0.0172x1000=17.29mm

S= Sc+Si

S=5+17.29=22.29mm Say 23mm

Total settlements 23mm, It is less than 25mm hence safe as per IS 1904-1986.

IEs

pBSi)1(

2µ−

=

mxSi 0172.095.02500

)3.01(225

2

=−

=

4.0 BORE-LOGS

:BH-1

:Rotary

: 15/08/2014

: 15/08/2014

De

pth

(m

)

15 30 45 N

0.0

1.0 3 5 7 12 SPT

2.0 39 SPT

Project : Proposed Construction of Residential Apartment at Selaiyur

G.W.T

Typ

e o

f S

am

ple

s

Type of Boring

Ended on

Started on

:100mm

: Ref. FigLocation

R.L

of L

aye

rs

50 Blows for 9Cm

SPT Details

Dia of Boring

:(-)3.20m

Soil Description

Total Depth : 5.0m

Graphical Representation of SPT

IS C

lassific

atio

n

So

il P

rofile

s

SM

Brownish Moorum SM

Bore Hole No.

Brownish Coarse

Sand

2.00

1.00

0 10

20

30

40

50

70

60

80

90

10

0

6

3.0 SPT

4.0 - - - >100 SPT

5.0 Rock

Soil Profile at BH-1 Location

Borehole Terminated at 5.0m Below Ground Level.

50 Blows for 0Cm

Core Recovery-5%

Soft Disintegrated

Rock GP

Fractured Hard

Rock Ve

ry

Po

or

5.00

4.00

6

5.0 TEST RESULTS

1

NM

C

WL

WP

I P Ic

Fre

eS

well

Gra

vel

Co

ars

e S

an

d

Med

ium

San

d

Fin

e S

an

d

Silt

& C

lay

Co

hesio

n, C

(kg

/Sq

.cm

.)

An

gle

of

fric

tio

n

0.0 0.0

12 1.0 1.0 13 2.61 3 46 16 11 24

>100 2.0 2.0 12 2.57 36 13 10 19 22

>100 3.0 3.0

>100 4.0 4.0

Rock 5.0 5.0


N' V

alu

e

SUMMARY OF TEST RESULTSIndex Properties (%)

Sp

ecif

ic G

ravit

y Grain Size Analysis (%)

Dep

th (

m)

UC

C S

tren

gth

(kN

/Sq

.m)

Termination Depth: -:5.0m

Direct Shear

Brownish SAND

BH NoS

oil D

escri

pti

on

Dep

th (

m)

So

il C

lassif

icati

on

Ground Water Level:(-)3.20m

Brownish Moorum

Soft Disintegrated Rock

Fractured Hard Rock

SM

SM

GP

Very

Poor

7

6.0 NATURAL MOISTURE CONTENT

Project : Proposed Construction of Residential Apartment at Selaiyur Date:20/08/2014

Method: IS-2720 P-2

BH.No/ Pit no

Natural Moisture Content Data Sheet

1 1BH.No/ Pit no

Depth (m)

Tare No 14 70 91 108

Wt of Tare (gr) 28.17 27.19 27.50 28.92

Tare + Soil (gr) 55.34 48.41 61.79 52.20

Tare+Dry soil (gr) 52.19 45.90 58.25 49.79

Wt of Water (gr) 3.15 2.51 3.54 2.41

Wt Dry soil (gr) 24.02 18.71 30.75 20.87

Water Content (%) 13.11 13.42 11.51 11.55

Average Water

Content (%) 13 12

2.01.0

1 1

8

7.0 SPECIFIC GRAVITY

BH.No 1 BH.No 1

Depth(m) 1.0 Depth(m) 2.0

Pycnometer number 36 58 Pycnometer number 19 8

Weight of bottle w1 g 33.2200 27.7900 Weight of bottle w1 g 34.8100 32.4500

Weight of bottle + soil w2 g 41.6400 40.5000 Weight of bottle + soil w2 g 48.4300 44.2400

Weight of bottle + soil + water w3 g 92.4500 88.5000 Weight of bottle + soil + water w3 g 90.6400 89.6300

Weight of bottle full of water w4 g 87.2500 80.6700 Weight of bottle full of water w4 g 82.3100 82.4300

w2-w1 g 8.4200 12.7100 w2-w1 g 13.6200 11.7900

w2-w1

(w4-w1)-(w3-w2)2.61491 2.60451

w2-w1

(w4-w1)-(w3-w2)2.57467 2.56863

2.61 2.57Average value Gs Average value Gs

Weight of soil

Specific gravity

SPECIFIC GRAVITY TEST


Specific gravity

Weight of soil

9

8.0 GRAIN SIZE ANALYSIS


BH 1

Depth

% Soil

retained

Cumulative %

FinerAverage Sieve

PSR % F % size (mm)(1) (2) (3)

3.38 96.62 4.750

45.59 51.03 3.375

11.35 39.68 1.500

3.25 36.43 0.800

1.79 34.65 0.513

4.43 30.22 0.319

2.81 27.41 0.181

3.87 23.53 0.113

Average Particle Diameter = 2.0085

BH 1

Depth

% Soil

retained

Cumulative %

FinerAverage Sieve

PSR % F % size (mm)(1) (2) (3)

36.47 63.53 4.750

12.98 50.55 3.375

5.60 44.95 1.500

3.01 41.94 0.800

1.88 40.06 0.513

7.49 32.57 0.319

5.66 26.91 0.181

5.84 21.07 0.113

2.4258

Gravel

Fine Medium Coarse Fine Medium Coarse Fine

% Particle Size 2.0 %

3 Gravel 36

46 0.207 Coarse Sand 13

16 4.200 Medium Sand 10

11 Fine Sand 19

24 Silt & Clay 22

Gravel

Coarse Sand

Medium Sand

Fine Sand

0.075

0.184

4.002

Particle Size

Silt & Clay

1.0

0.150

0.075

4.750

1.000

0.600

0.425

0.212

passing 0.075

Sieve Aperture size used

(mm)

1.000

173.22

43.82

8.40

2.000

0.92

1.41

0.51

0.44

Product of

2.60

Sand

232.873

1.02

0.66

0.97

2.39

(1) x (3)

2.41

192.820

Product of

Columns(1) x (3)16.06

153.88

17.02

4

5

5

4

S.No.

6

7

Sieve Analysis Test

1

2

3

Sieve Aperture size used

(mm)

4.750

1.0m

S.No.

2.000

Clay

Average Particle Diameter =

0.600

passing 0.075

0.425

7

6

Silt

0.212

0.150

9

8

8

9

2.0m

2

1

3

0

10

20

30

40

50

60

70

80

90

100

0.001 0.010 0.100 1.000 10.000Particle size [mm]

I Depth II Depth

Cum

ula

tive

P

erc

enta

ge F

iner

D10 =D30 =D60 =

D10 =D30 =D60 =

Depth = Depth =

Cu =

Cc =

Cu =

Cc =

10

PROPOSED CONSTRUCTION OF RESIDNTIAL APARTMENT AT … · Based on soil strata open shallow...

Documents

Transcript of PROPOSED CONSTRUCTION OF RESIDNTIAL APARTMENT AT … · Based on soil strata open shallow...