RATE CONTRACT FOR SUBSOIL & GEOTECHNICAL INVESTIGATION OF VARIOUS PROJECTS (FROM SEPTEMBER 2026 TO AUGUST 2031) AT KEMPEGOWDA INTERNATIONAL AIRPORT, BENGALURU

Airside

MOBILIZATION & DEMOBILIZATION

Mobilization of 1 No. hydraulically operated rotary drilling rig equipped with auto-trip SPT facility, double/triple tube core barrels, diamond/TC bits, and all necessary tools, tackles, accessories, operating crew, and stabilization setup to the project site, including setup, dismantling, and demobilization upon completion of work as per instruction of the Engineer-in-Charge. (Note: Paid per distinct call-out/work order under the ARC).

Mobilization of ancillary equipment (high-pressure compressor, water tanker, generator, welding machine, etc.) required for drilling/field operations to the project site, including dismantling and demobilization.

Shifting of drilling rig, equipment, accessories, and platform setup from one borehole location to another subsequent location within a shifting distance up to 50 meters.

Additional shifting charges for moving the drilling rig and setup beyond the initial 50 meters, measured along the shortest accessible route between locations.

DRILLING, BORING & CORE SAMPLING

Boring minimum 100mm diameter exploratory boreholes in all types of soil up to Standard Penetration Test (SPT) blow count N < 60, using rotary wash boring or auger methods, including casing or bentonite slurry stabilization, recording water table levels, and handling standard field collection protocols as per technical specifications.

Drilling 100mm diameter exploratory boreholes in dense/hard/refusal soil strata where 60 < N < 100 or core recovery is less than 10% using a Tungsten Carbide (TC) bit, including casing, recording water table levels, and sample collections as per technical specifications.Supplying rock core boxes, including proper arrangement, preservation, systematic labeling, and securing of recovered rock core samples.

Drilling of exploratory boreholes in refusal strata (N>100) to Highly weathered rocks (RQD<25% & UCS<5 MPa) using single/double tube core barrels with TC or diamond bits, including preservation of core samples in standard core boxes and logging. Supplying rock core boxes, including proper arrangement, preservation, systematic labeling, and securing of recovered rock core samples.

Drilling of exploratory boreholes in highly weathered to moderately weathered rocks i.e., 25<RQD<70., including cleaning, core box preservation, and detailed logging. Supplying rock core boxes, including proper arrangement, preservation, systematic labeling, and securing of recovered rock core samples.

Drilling of exploratory boreholes in moderately weathered rocks to Intact rocks i.e., 70<RQD<100 and core recovery greater than 10%. including careful extraction, preservation in core boxes, and rock logging as per the latest standards. Supplying rock core boxes, including proper arrangement, preservation, systematic labeling, and securing of recovered rock core samples.

Providing, installing, and extracting temporary steel casings during drilling operations to support unstable borehole walls where specialized slurry stabilization alone is insufficient.

Permanent borehole abandonment, including complete backfilling via environmental cement-bentonite grout injection and structural restoration of the surface to match original site conditions.

FIELD TESTS & IN-SITU SAMPLING

Conducting Standard Penetration Test (SPT) in boreholes at 1.0m intervals for the first 5.0m below existing ground level (EGL) and every 1.5m interval thereafter or at every change of strata, including recording penetration resistance blows (e.g., 99 blows/10cm), recovering disturbed split-spoon samples, labeling, and airtight preservation.

Extracting 90mm diameter, 450mm long Undisturbed Soil Samples (UDS) from boreholes using open-drive thin-walled samplers or specialized Shelby Tubes, including paraffin wax sealing of both ends, labeling, and safe transport to the laboratory. (Applicable only in soil layers where N < 60).

Collection of Undisturbed Soil Samples (UDS) interspersed mid-way between standard SPT depth intervals, explicitly executed within cohesive/clayey soil strata as directed by the site representative.

Conducting Dynamic Cone Penetration Test (DCPT) from existing ground level down to a depth of 3.0 meters below EGL, recording blow counts per 100mm/300mm penetration.

Conducting Dynamic Cone Penetration Test (DCPT) extension beyond 3.0 meters depth down to a maximum of 10.0 meters or refusal, plotting continuous soil resistance profiles.

Conducting Mackintosh Probe Tests to rapidly profile very soft/loose shallow deposits, including driving a conesheaded rod and recording continuous penetration resistance data.

Conducting In-situ Borehole Permeability Tests via the Falling Head method in soil or rock strata as per IS 5529 (Part 1).

Conducting In-situ Borehole Permeability Tests via the Constant Head method in highly permeable soil or rock formations as per IS 5529 (Part 1).

Conducting In-situ Single Packer (Lugeon) water pressure permeability tests in fractured rock strata at designated pressure increments to assess joint conductivity.

Conducting In-situ Double Packer water pressure permeability tests to isolate and verify distinct, specific rock fractures or targeted zones within a borehole.

Lowering a high-resolution, waterproof borehole video camera inspection system to visually log downhole strata boundaries, soil layers, and structural anomalies.

Performing an Optical Borehole Televiewer (OBI) survey to generate a continuous, oriented, 360-degree high-resolution digital image of the borehole wall for fracture orientation mapping.

Extracting undisturbed groundwater samples (minimum 1 liter) from boreholes using clean, non-reactive containers, sealing, and transferring to the laboratory for environmental chemical testing.

Plate Load Test

Conducting Field Plate Load Test (PLT) at the designated foundation level as instructed by the representative using a standard mild steel plate (size 300mm to 750mm square/circular), excluding the cost of the dead load reaction system. Rate includes excavation, seating, dial gauge monitoring, and complete reporting.

Conducting Field Plate Load Test (PLT) at the designated foundation level, inclusive of providing, erecting, and dismantling a complete gravity loading (Kentledge) or anchor truss reaction system supporting a dead load up to 40 Metric Tons.

Conducting Field Plate Load Test (PLT) at the designated foundation level, inclusive of providing, erecting, and dismantling a complete gravity loading (Kentledge) or anchor truss reaction system supporting a dead load greater than 40 Metric Tons and up to 100 Metric Tons.

Conducting Field Plate Load Test (PLT) at the designated foundation level, inclusive of providing, erecting, and dismantling a complete gravity loading (Kentledge) or anchor truss reaction system supporting a dead load greater than 100 Metric Tons and up to 150 Metric Tons.

Calculating the Coefficient of Earth Pressure active / passive / @rest earth cases for wall designs

GEOPHYSICAL INVESTIGATION

Conducting Electrical Resistivity Survey (ERT) using Wenner/Schlumberger 4-electrode profiling configuration down to a minimum depth of 5.0 meters below EGL, including processing data and plotting apparent resistivity soundings.

High-resolution Ground Penetrating Radar (GPR) Survey to detect shallow bedrock levels, buried utilities, cavities, or structural anomalies using multi-frequency antennas.

Conducting Seismic Refraction Survey along designated profiling lines, including setting up geophone spreads, generating surface energy impacts, and interpreting dynamic wave velocity layers.

Conducting Cross-Hole Seismic Tests using the 3-borehole method to determine dynamic soil properties, inclusive of providing/grouting PVC guide casings in auxiliary holes, lowering geophones, generating impulses, and data interpretation.

Conducting Down-Hole Seismic Tests using a single instrumented borehole and an external surface polarized shear wave strike plate to record interval compression and shear wave arrivals.

Conducting Ambient Noise Microtremor Survey (Horizontal-to-Vertical Spectral Ratio - HVSR) to calculate the fundamental resonant frequency and amplification factors of soil overburden.

Calculating the Modulus of Subgrade Reaction to evaluate settlements

Trial Pits

Conducting trial pit of minimum size 1m x 1m x 3m with high power hydraulic excavator by following all safety norms at site. Collection of bulk samples (min. 15 kgs) at 0.6 to 1.0m, 1.5 to 1.8m, 2.6 to 3.0m below ground level

Depth till 1.2m below EGL

Depth between 1.21 to 2.0m below EGL

Depth between 2.1 to 3m below EGL

Collection of UDS from trial pits from subgrade upto 1m Below the subgrade

Evaluation of maximum dry density (MDD) as per modified Proctor method

Evaluation of field dry density (FDD) at locations as shown by the BIAL representative

Performing 4days soaked CBR at the compacting degree as per the FDD and evaluating CBR for the subgrade.

Free Swell and Shirnkage tests

Conducting DCPT at 1m depth

Conducting DCPT at 1.2m to 5m depth

Conducting DCPT at >5.1m depth

Laboratory Tests

Soil Samples

Modified Proctor

Permeability/ Percolation Tests

Natural moisture content & Bulk / Dry density

Atterberg limits

Grain Size analysis and hydrometer, Moisture content and Density (bulk and dry) & Specific Gravity

Conducting 4 days soaked California Bearing Ratio test (laboratory CBR on remoulded samples at 97%MDD).

Direct shear tests

Consolidated drained (CD) tri-axial test(report C’, & E’)The test shall include the following stages:

Per Bore Hole

Per Bore Hole

Per Bore Hole

Per Bore Hole

Unconsolidated-undrained triaxial test

Chemical tests like pH, sulphates, chorides, harmful salts for soil and for water

Natural Moisture Content

Tests for swelling characteristics of soil -Shrinkage Limit and Free Swell Index

UCS Test in Cohesive soil on UDS samples

Testing of UDS for Triaxial UU / UC Test & density

Testing of UDS for consolidation

Testing of UDS for swelling pressure

Rock Samples

Tests on rock core - Water absorption and Porosity of rock sample

Specific Gravity of rock sample

Unconfined compressive strength of rock cores - Without saturation

Unconfined compressive strength of rock cores - With 7 days saturation

Point Load Index Test on Rock Sample

Test on Rock sample for Deformation Modulus and Poisson’s Ratio including submission of stress strain graphs

Bulk and Dry unit weight

LABORATORY TESTS - On Cut soil & Borrow areas

Atterberg limits (only in Cohesive soils)

Grain Size analysis and hydrometer, Moisture content and Density (bulk and dry) & Specific Gravity

Modified Proctor Test (on samples collected from trial pits)

Conducting 4 days soaked / Unsoaked California Bearing Ratio test (laboratory CBR on remoulded samples at 97%MDD). Location of sampling and borehole number to be obtained from BIAL representative.

Free Swell Index (Cohesive Soils)

Swelling Pressure (On UDS samples of Cohesive soils)

GROUNDWATER & INSTRUMENTATION

Supply, fabrication, installation, and sealing of a standard Casagrande-type open Standpipe Piezometer inside completed boreholes to monitor long-term equilibrium groundwater levels, including a lockable surface protective cap.

Supply, calibration, installation, and grouting of high-precision Vibrating Wire Piezometers (VWP) at specified downhole depths, including routing signal cables to the surface for automated data logger hookup.

Field mobilization visit by a technician to read, log, and maintain piezometers or manually sound long-term groundwater levels over an elongated multi-month operational monitoring lifecycle.

Reports