\( \left\{\begin{array}{l}\text { Describe in details the types of: } \\ i \text { is In-situ tests. } \\ i i_{i} \text { Laborators test done on soil. }\end{array}\right. \)

Certainly! Let's delve into the details of in-situ tests and laboratory tests conducted on soil. ### i. In-situ Tests In-situ tests are conducted directly on the soil at the site of interest. These tests provide valuable information about the soil's properties in its natural state, which is crucial for geotechnical engineering, construction, and environmental assessments. Here are some common types of in-situ tests: 1. **Standard Penetration Test (SPT)**: - **Description**: A widely used test where a split-barrel sampler is driven into the soil at the bottom of a borehole by a hammer falling from a specified height. The number of blows required to drive the sampler a certain distance (usually 300 mm) is recorded. - **Purpose**: To estimate the soil's density and strength, and to classify the soil type. 2. **Cone Penetration Test (CPT)**: - **Description**: A cone-shaped penetrometer is pushed into the ground at a constant rate. The resistance to penetration is measured, providing continuous profiles of soil resistance. - **Purpose**: To assess soil stratigraphy, strength, and other geotechnical properties. 3. **Vane Shear Test**: - **Description**: A vane is inserted into the soil and rotated to measure the torque required to shear the soil. This test can be performed in soft clays and silts. - **Purpose**: To determine the undrained shear strength of cohesive soils. 4. **Pressuremeter Test**: - **Description**: A cylindrical probe is inserted into a borehole, and pressure is applied to expand the probe against the soil. The pressure and volume changes are recorded. - **Purpose**: To evaluate the in-situ stress-strain behavior of the soil. 5. **Field Permeability Test**: - **Description**: Tests such as the falling head or constant head tests are conducted to measure the permeability of soil in situ. - **Purpose**: To determine the hydraulic conductivity of the soil, which is essential for groundwater flow and contaminant transport studies. 6. **Dilatometer Test (DMT)**: - **Description**: A flat dilatometer is inserted into the ground, and pressure is applied to measure the expansion of the membrane against the soil. - **Purpose**: To assess the in-situ stress, stiffness, and strength of the soil. ### ii. Laboratory Tests on Soil Laboratory tests are performed on soil samples collected from the field to determine various physical and mechanical properties. These tests are essential for understanding soil behavior under different conditions. Here are some common laboratory tests: 1. **Grain Size Analysis**: - **Description**: This test determines the distribution of particle sizes in a soil sample using sieves and/or hydrometer methods. - **Purpose**: To classify the soil and understand its drainage characteristics. 2. **Atterberg Limits Test**: - **Description**: This test measures the plasticity of fine-grained soils by determining the liquid limit, plastic limit, and shrinkage limit. - **Purpose**: To classify soils and assess their behavior under varying moisture conditions. 3. **Proctor Compaction Test**: - **Description**: This test determines the optimal moisture content and maximum dry density of soil by compacting it in a mold using a specified energy. - **Purpose**: To evaluate the compaction characteristics of soil for construction purposes. 4. **Unconfined Compressive Strength Test (UCS)**: - **Description**: A cylindrical soil sample is subjected to axial loading until failure without any confining pressure. - **Purpose**: To determine the strength of cohesive soils. 5. **Triaxial Compression Test**: - **Description**: A cylindrical soil sample is subjected to controlled confining pressure and axial loading to simulate in-situ conditions. - **Purpose**: To evaluate the shear strength parameters of soil under different drainage conditions (drained or undrained). 6. **Consolidation Test**: - **Description**: A soil sample is subjected to a vertical load in a consolidation apparatus to measure the rate and amount of settlement over time. - **Purpose**: To assess the compressibility and settlement characteristics of cohesive soils. 7. **Permeability Test**: - **Description**: Conducted in a laboratory to measure the hydraulic conductivity of soil samples using constant or falling head methods. - **Purpose**: To evaluate the soil's ability to transmit water, which is critical for drainage and foundation design. 8. **California Bearing Ratio (CBR) Test**: - **Description**: A test that measures the strength of subgrade soil for pavement design by comparing the penetration resistance of a soil sample to that of a standard crushed rock. - **Purpose**: To assess the suitability of soil for use in road construction. These tests, both in-situ and laboratory, are essential for understanding soil behavior and ensuring safe and effective engineering practices in construction and environmental management.