SUB-SOIL (GEOTECHNICAL) INVESTIGATION WORKS AT VARIOUS DISTRICT OF ASSAM

In-situ Sub-Soil Investigation and supplementary Laboratory Tests

Sub-Soil (Geotechnical) Investigation works at Various District of Assam

Scope of work under tender

SL Description of Item

1 Mobilization & Demobilization covering all nine (9th ) Locations

* Mobilization expenses towards cost of transportation of plant and equipment, personnel,

set up of equipment at every boring site from the start of work and their withdrawal on

completion of work.

2 Manual Percussion Boring

* Drilling exploratory boreholes by Manual Percussion Boring (hand boring) up to the required

depth from E.G.L. up to Hard strata or up to a refusal (N>50) whichever comes earlier

including conduction of S.P.T. at 1.5 m interval, collection of disturbed samples in soil only

(except gravelly deposits, hard and stiff clay, weathered rock, rock etc.) Collection of

undisturbed samples in clayey soils only (except sand and gravelly deposits, hard and stiff

clay, weathered rock, rock etc.) as per relevant IS code of practices Conducting laboratory

test on collected soil samples as per relevant IS Code: a) UCS test on cohesive (clayey) soils

b) Direct shear test on granular (sandy) soils c) Liquid limit d) Plastic Limit e) Specific gravity

f) Grain Size (dry sieving). Only One bore hole Test to be conducted per site.

* From E.G.L. up to 15.0 m

3 Report Preparation: Summary of tests conducted in-situ and in the Laboratory; Graphical

Plots of data where relevant; followed by Analysis and Recommendations based on

(restricted to the limitations of) the tests actually conducted In-situ and in the Laboratory

as per Clients requirements. Note: The details of the Analysis and Recommendations shall

be limited to as described in the following sub-sections.

Drilling of 01 borehole of 150/76 mm diameter in all types of soil/rock up to maximum

15 m depth below EGL by using Rotary Drilling rigs.

Performing Standard Penetration Test (SPT) in the boreholes at intervals of 0.75 m up

to the top 6m and at intervals 1.5m below 6m or in every change of strata in both cohesive

and non-cohesive soils up to the depth of 15m.

Collection of UDS Samples in cohesive / semi-cohesive soils at alternatively with SPT, if

possible depending on the soil strata.

Conducting the following laboratory test on soil samples as per IS codes.

Recording Ground Water Table depth during investigation work.

Preparation and Submission of Geo-technical report.

Boring and Drilling

Boreholes were sunk by deploying heavy duty rotary drilling rig using the conventional

rotary drilling process. Methodology followed for boring confirmed to IS: 1892. Boring

was effected by the cutting action of rotating bit with bentonite slurry circulation and by

stabilising the sides of the boreholes using casing pipes/bentonite slurry up to required

depth to prevent side collapse. While this method was adequate to bore through the stiff

soil stratum, progress of boring slowed down considerably near the soil - rock interface,

including weathered rock formations. In such cases, further drilling work was carried out

by using NX size double tube core barrel with TC (Tungsten Carbide) bits.

Disturbed samples have been collected from split spoon sampler by conducting the

standard penetration tests below the existing ground level as presented in the respective

field bore logs.

Undisturbed samples (UDS) were attempted and collected in the boreholes at River

crossing with cohesive / semi cohesive layers using 100mm diameter thin walled

sampling tubes. Upon sampling, both ends of the sampling tube were hermetically sealed

with paraffin wax and labelled.

The SPT, UDS sampling depth for each borehole has to be mentioned in the bore log.

List of Sites where SPT Soil Testing is to be conducted:

GEO LOC GEO LOC

Cust. Code Dealer Name Location District State

178186 (BPCL) NES MORAN BARBARUA MORAN DIBRUGARH ASSAM 94.867

180022 ABANI FILLING STATION DIBRUGARH DIBRUGARH ASSAM 94.884

187194 DHAN & RANI FUEL STATION DEMOW SIBSAGAR ASSAM 94.758

177685 NES KAZIRANGA KAZIRANGA GOLAGHAT ASSAM 93.48

156030 PETRO STATION

JORHAT ASSAM 94.149

215460 BHOLA GOGOI FILLING STATION BYPASS

SIBSAGAR ASSAM 94.646

215898 BOGIBEEL FILLING STATION KULAJAN DHEMAJI ASSAM 94.721

TENGAKHAT FUEL SERVICE

188621 DIBRUGARH ASSAM 95.075

STATION TENGAKHAT

210008 DJ FILLING STATION DULIAJAN DIBRUGARH ASSAM 95.271