There are several geotechnical laboratory testing and analysis techniques covered in the optional subject. These techniques are used to investigate and evaluate the engineering properties of soil and rock materials. Some of the key techniques include:

1. Soil Classification:
Soil classification is an essential part of geotechnical engineering. Different classification systems such as the Unified Soil Classification System (USCS) and the AASHTO soil classification system are used in laboratory testing to classify soils based on their physical properties.

2. Soil Compaction:
Soil compaction tests are performed to determine the maximum dry density and optimum moisture content of a soil. These tests, such as the Proctor compaction test, help in designing and controlling the compaction of soils to achieve the desired engineering properties.

3. Permeability Testing:
Permeability tests are conducted to determine the hydraulic conductivity of soils. Techniques such as constant head permeability test and falling head permeability test are used to evaluate the flow of water through soil samples.

4. Shear Strength Testing:
Shear strength tests are performed to determine the strength and stability of soils under different loading conditions. Tests such as direct shear test, triaxial shear test, and unconfined compression test are conducted to evaluate the shear strength parameters of soils.

5. Consolidation Testing:
Consolidation tests are carried out to determine the settlement characteristics and compression behavior of cohesive soils. The oedometer test is commonly used to measure the consolidation properties of soil samples.

6. California Bearing Ratio (CBR) Test:
The CBR test is used to evaluate the strength and bearing capacity of subgrade soils. It measures the resistance of a soil sample to penetration under standardized conditions, providing an indication of its load-bearing capacity.

7. Index Property Testing:
Index property tests, such as the determination of moisture content, specific gravity, and grain size distribution, are conducted to obtain basic information about the physical properties of soils.

These laboratory testing and analysis techniques provide valuable information about the geotechnical properties of soils and rocks. They are essential for designing and constructing various types of geotechnical projects such as foundations, embankments, and retaining structures.