Borehole method involves drilling vertical or inclined holes into the ground to obtain soil samples and conduct in-situ tests at various depths. These boreholes typically range from a few meters to several tens of meters in depth, depending on the project requirements and the depth of the soil layers being investigated

Sampling

• Soil samples are collected at regular intervals as the borehole progresses. These samples are extracted using tools such as split-spoon samplers, thin-walled tube samplers, or rotary drilling techniques, ensuring representative samples of the soil strata are obtained.

In-Situ Testing

• Various in-situ tests may be performed within the borehole to assess soil properties without disturbing the soil structure. Common in-situ tests include Standard Penetration Test (SPT), Cone Penetration Test (CPT), vane shear test, and pressuremeter test.

Logging

• As the borehole advances, detailed logs are maintained, recording information such as soil type, color, texture, moisture content, presence of groundwater, and any other relevant soil characteristics. This logging helps in correlating soil properties with depth and identifying potential changes in soil behavior.

Sampling Equipment

• Depending on the soil conditions and project requirements, different drilling methods and equipment may be used, including rotary drilling rigs, percussion drills, auger rigs, or wireline coring rigs. The choice of equipment depends on factors such as soil type, accessibility, and desired depth of investigation.

Laboratory Testing

• After sampling, soil specimens are transported to the laboratory for further testing and analysis. Laboratory tests may include grain size analysis, moisture content determination, Atterberg limits tests, consolidation tests, shear strength tests, and chemical analysis to determine soil composition and engineering properties.

Interpretation and Reporting

• The data collected from soil investigation borehole methods are analyzed and interpreted to develop a comprehensive understanding of the subsurface conditions. This information is then used to generate detailed reports and geological profiles, providing valuable insights for engineering design, foundation recommendations, and construction planning.