Geotechnical Investigation

SPT is an in-situ test used to determine the strength and density of soil. A split-spoon sampler is driven into the ground using a standard hammer, and the number of blows required for 30 cm penetration (N-value) is recorded. It helps assess soil stratification, bearing capacity, and liquefaction potential, making it essential for foundation design.

Trial pits are shallow, manually or mechanically excavated openings used for direct visual inspection of subsurface conditions. They help identify soil layers, groundwater levels, and possible obstructions. Typically up to 3 meters deep, trial pits are ideal for small-scale investigations where sampling and logging of soil strata are required for preliminary foundation or geotechnical assessment.

The Field Density Test determines the in-situ density of soil to assess compaction quality. Common methods include the Sand Cone Method, Core Cutter Method, and Nuclear Density Gauge. It is essential for verifying whether soil compaction at construction sites meets design specifications, ensuring stability and load-bearing capacity of structures.

SCPT is an in-situ test that measures soil resistance by pushing a cone-tipped probe vertically into the ground at a constant rate (typically 20 mm/s) without dynamic loading. It provides continuous profiles of cone resistance (qc), sleeve friction (fs), and pore water pressure (u), helping assess soil stratification, relative density, and bearing capacity. It is especially effective in soft to medium cohesive and cohesionless soils.

DCPT is an in-situ test used to evaluate soil strength and compaction by driving a cone into the ground using a standard hammer. The number of blows required for each 300 mm (30 cm) penetration is recorded. It provides quick estimates of soil consistency, bearing capacity, and stratification, making it suitable for shallow foundations and road subgrade assessments.

The Field Vane Shear Test measures the undrained shear strength of soft cohesive soils by inserting a four-blade vane into the ground and rotating it to cause failure. The torque required to rotate the vane is recorded and used to calculate the shear strength. This test is ideal for clayey soils, helping to assess stability for foundations and earthworks in low-strength materials.

The Field CBR Test evaluates the strength and bearing capacity of subgrade soils for pavement and road construction. A plunger is driven into the soil at a constant rate, and the resistance is compared to that of a standard material. The CBR value is calculated as the ratio of the pressure required to penetrate the soil to the pressure required for standard material, providing a measure of soil compaction and suitability for load-bearing.

The Block Vibration Test is used to determine the dynamic properties of soil and concrete by applying controlled vibrations to a concrete block placed on the soil. The test measures parameters such as natural frequency, damping, and stiffness, providing insights into the soil's ability to support vibrations, which is crucial for the design of machine foundations and structures subjected to dynamic loads.