BORGAON_BHANDARA

8/8/2019 BORGAON_BHANDARA

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Report

On

SOIL TESTINGFOR

CONSTRUCTION OF GSM-GBT TOWERSITE NAME BORGAON BHANDARA

Mr. Sopan H. AkreAt Chicholi Post Dhandla, Tah: Mouda, Disst: Nagpur

FORVIOM NETWORKS

IMPLEMENTING AGENCY

VIOM NETWORKSNagpur

P.T.MASE & ASSOCIATESConsulting Civil Engineers & Structural Engineers

Project Management Consultants

Structural Audit & Assessment Division

Civil Engineering Laboratory & Research Centre

Planning Consultants

240 B 1, BAJAJ NAGAR, NAGPUR-440 010

TEL.NOS: 0712 223 4340, 2237309

FAX NO: 0712 223 4979, 223 3430

MOBILE 098222 20919


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INDEX

SR. NO. PARTICULAR

1. INTRODUCTION

2. TERMINOLOGY

3. SITE INVESTIGATION & EXPLORATION

4. CHARACTERISTICS OF SOIL


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Summary of Test

As per the various test carried out, our recommendations are as

follows.

1.Safe bearing capacity of soil with factor of safety 2.5 is 7.0 T/m2 at3.0 mt depth

2.Remove Excavated soil up to 2.0mt.3.From 2 mt to 3.0 mt use excavated soil for back filling with

addition of 50% external murum or sand.

4.R. C. C. open foundation is recommended for tower, DG and Shelterfoundation.

5.No water table found.6.No chemicals found in soil.7.Raise plot level by 300 mm to avoid lodging in rainy season.

CERTIFICATE

It is hereby certified that the document titled Scope of Work and

Specifications for Soil Investigations and Testing for Telecom towers

for Viom Networks, Version 1.0, dated 4th August, 2010 issued by

Viom Networks has been strictly adhered to.

Certified by: Dr. D. P. Mase

Designation: Structural Engineer

Qualification: B.E. (Civil). M. Tech (Structure), Ph. D. (Civil)

Chartered Engineer No: M-123484/0

MIE, MICI, MACI, MACE.


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INTRODUCTION

The purpose of the soil investigation is to arrive at an optimum design for the

tower foundations. The telecom towers are generally 3 - legged Or 4 legged

braced steel structures varying from 30m to 60m height. The weight ranges

from 5 to 15 tons depending on the type of tower. Under extreme conditions of

wind loading, the load on each leg will be in the range of 25 to 100 ton in

compression, 25 to 100 tons in uplift and 2 to 10 tons in lateral thrust. In most

cases, the uplift capacity of the foundation governs the design.

Scope & Objective of the work:-

The Scope of work includes following points,

1) A trial pit carried out up to depth of 3 meters.2) Collection of disturbed sample3) Conducting laboratory tests4) Preparing soil profile5) Locating ground water level (GWL)6) Preparation and submission of report


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TERMINOLOGY

Following are the terminologies used in the report. (IS: 1904 1966)

1) Safe Bearing Capacity (SBC) The maximum intensity of the loading that the soil will safely carry without risk of shear failure, irrespective of any consolidationsettlement that may results.

2) ClayAn aggregate of microscopic and sub microscopic particles derivedfrom the chemical decomposition and disintegration of rockconstituents.

It is plastic within a moderate to wide range of water content. Theparticles are less than 0.002 mm size.

3) Firm ClayClay, which had its natural moisture content, can be moulded bysubstantial pressure with the fingers and can be excavated with aspade.

4) Soft ClayClay, which had its natural moisture content can be easily moulded

with the fingers and readily excavated.

5) Stiff ClayClay, which had its natural moisture content can not be moulded withthe fingers and requires a pick or pneumatic spade for its removal.

6) FoundationThese parts of the structure, which is in direct with and transmittingload to the ground.

7) Raft Foundation

A foundation continuous into directions, covering an area equal to orgreater than the best area of the building or structure.

8) GravelCohesion less aggregates of rounded, sub rounded, angular, subangular or flat fragments of more or less unaltered rocks or minerals,90% of the particles having a size greater than 2 mm less than 60mm.


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9) Sand

Cohesion less aggregates of rounded, sub rounded, angular, subangular or flat fragments of more or less unaltered rocks or minerals,90% of the particles having a size greater than 0.06 mm less than 2.0

mm in size.

10) Coarse sandSand which contains 90% of particles of size greater than 0.6 mm andless than 2.0 mm.

11) Medium SandSand, which contains 90% of particles of size greater than 0.2 mmand less than 0.6 mm.

12) Fine SandSand, which contains 90% of particles of size greater than 0.06 mmand less than 0.2 mm.

13) SiltA fine granular soil with little or no plasticity. If shaken in the palm ofthe hand, a pat of saturated inorganic silt expels enough water tomake its surface appears glossy. If the pat is stressed or squeezedbetween the fingers, it surface again becomes dull. The size ranges forsilt are as follows:-

a) Coarse Silt : 0.06 to 0.02 mm

b) Medium Silt : 0.02 to 0.006 mmc) Fine Silt : 0.006 to 0.002 mm

14) Soft RockA rocky cemented material, which offers a high resistance to diggingup with pick axes and sharp tools, but which does not normallyrequires blasting or chiselling for excavation.

15) Hard RockA rock which offers a high resistance to digging up with pick axes and

sharp tools and normally which requires blasting or chiselling forexcavation. Also hard rock offers a high resistance to metal tools andgenerates heavy sparks at the time of excavation.

16) Black Cotton SoilInorganic clays of medium to high compressibility, which is generallycohesive in nature and exerts swelling pressure when comes incontact with moisture or water.


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SITE INVESTIGATION & EXPLORATION

The investigation of the site is an essential prerequisite to the construction of

all civil engineering work with a view to assess the general suitability of the sitefor the proposed tower and enable in preparing an adequate and economicaldesign.

In particular, it is necessary to assess the changes that may occur during orafter the construction of the structure due to the choice of material or methodof construction, which may adversely, affects safety of structure or after itsperformance or utility. The investigation of the site is being carried out and inaccordance with the principles set by IS 1892 1979.

Before carrying out soil exploration programme, detail information about the

site is being collected.

Site exploration can be carried out by most common and satisfactory methodseven by IS 1892 1979 are,

a) Method of trial pitsb) Method of boringc) Heading

In our site exploration programme, we have adopted first method, i.e., method

of trial pit. In site exploration programme, particular attention shall be paid tothe ground water level, soil profile is being plotted and variation of soil strata ismarked according to the depth of excavation.

The sites where problem of water logging in rainy season may cause, in suchareas, it is desirable to determine the contour of the water table surface inorder to indicate the direction of the natural drainage and to obtain the basis ofthe design of intercepting drains to prevent the influx of ground water to thesite from higher grounds.


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LABORATORY TESTSCHARACTERISTICS OF SOIL

(AS PER IS: 1498 1970)(Reaffirmed in 1997)

1.Grain Size Analysis

Soil Sample from Borgaon Bhandara site collected from 1 Mt, 2 Mt, 3 Mt, depths was

tested for Engineering classification and opinion on presumptive Bearing Capacity

based on it. The dry Sieve analysis as per IS 2720 (PART IV) was conducted, the

results are as under. Settlement criteria considered for design is 25 mm. Trail Pit Size

2 x 2 x 3.0 mt. with manual Bore.

1 Mt. Depth Sample:-

Gravel : 19%Sand : 27%Silt & Clay : 54%





Engineering Classification : Stiff Clay

Depth of Water Table : 3.0 Mt below G.L.

Angle of internal friction at 3.0 : 26o

Atterberge Limit : Non Plastic at 2.0 Mt Depths

2.Determination of moisture content (As per IS 2720 (Part 2).The method adopted to find moisture content as per section 1-Oven-Drying method

(Standard Method).

The Percent of Water Content W

Moisture content (w)

= 18.12 %


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3. Specific gravity (As per IS 2720 (Part 3)

Section 1-fine Grained Soils

Section 2- Fine, medium and coarse grained soils.

The method adopted to find specific Gravity Gas Jar Method

Specific Gravity G= 2.592

4. Determination of liquid and plastic limit (As per IS 2720 (part 5) method

adopted for the determination of Liquid limit- Mechanical Method

5. Shrinkage Factors as per IS 2720 (Part 6).

Method adopted for Determination of Shrinkage Factor Remoulded Soil)

6. Determination of Dry Density- moisture content Relation By Constant massof Soil method (As per IS 2720 (Part 9). Method adopted Cylindrical metal tube

with base plate.

7. Ph value test as per IS 2720 (Part 26) - Determination of PH value. Appraturuse for PH- Electronic PH meter.

8. Sulphate Content Test & Chloride content Test- as per IS 2720 (Part XXVII) -Determination of total Soluble Sulphates.

SoilSample

BulkDensity

DryDensity

LiquidLimit

Plasticlimit

FreeSwellIndex

PH ChlorideContent

SulphidConten

Unit gm/cc gm/cc % % % ---- % %

1 mt 1.901 1.541 69.1 23.0 48.0 8.1 --- ---

2 mt 1.912 1.530 70.2 23.3 46.1 7.6 -- --

3 mt 1.922 1.561 70.1 22.1 44.1 7.4 -- --

The Soil contains particle from 1 mm to 10 mm size and can be classified as Stiff Clay. As

per IS 1904 Code of particle for structural safety of Building Shallow foundations.

(Second Revision) Table 2 considering factor of safety Two point five. The in situ strength

of this Stratumgenerally varies between 7 to 9 T/m2. lower value of 7 T/m2 is recommendedin present case at the depth of 3.0 Mt. Depth of tower foundation can rest at 3.0 Mt depth.


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Depth of Foundation

i) Depth below FGL for Tower : 3.0 Mt

ii) Depth below FGL for Civil Shelter : 2 Mt

iii) Depth of foundation for D.G. set : 2 Mt

iv) Foundation details : Suitable for Ground Base Tower

v) Back Fill : With external Non cohesive materialor External Murum. Mix with excavatedsoil from 2 mt to 3.0 mt Depth

Note: - At the time of selection for tower foundation, excavation depth recommended is

from the S.B.C. point of view. While selections of foundation type uplift force on tower

leg must be considered. The minimum depth of foundation required to resists uplift

force must be considered. Accordingly over burden on the foundations must be

checked.

Brief Description of Site

1. Site level from Road Site is located at plain ground and requires filling of 300mm above existing ground level to avoid water Lodging in future.

2. Trees at site- No Trees found on site.3. Nearby water bodies- No water bodies found in nearby area.4. Natural Strata found. No filled up Ground5. Water Table- No water table found in trial pit. No well or bore found in nearby

area.

6. Site Location Site is located in field and requires filling of 300 mm aboveexisting ground level to avoid water lodging in future.


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PHOTOGRAPHS OF BORGAON BHANDARA SITE


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