Subsurface investigation is a field of study that focuses on understanding the characteristics and properties of the soil and rock layers beneath the Earth's surface. This area of research is critical for a variety of engineering and environmental projects, such as the design and construction of buildings, bridges, and highways, as well as the assessment of groundwater contamination and geological hazards. Subsurface investigations typically involve the use of various techniques and tools, such as drilling, geophysical surveys, soil sampling, and laboratory testing, to gather data on the composition, porosity, strength, and moisture content of the subsurface materials. This information is then analyzed and used to make informed decisions about the feasibility, safety, and sustainability of proposed construction and development projects. Overall, subsurface investigation plays a crucial role in ensuring the success and longevity of infrastructure projects, as well as in protecting the environment and public health.