In conclusion, the fundamentals of geotechnical engineering are essential in understanding the behavior of soil and rock materials. The concepts of soil formation and classification, soil properties, effective stress and pore water pressure, shear strength, and drainage and flow through soil are crucial in designing and constructing safe and stable infrastructure projects.

Water flow through soil pores is governed by Darcy’s Law . Understanding permeability is vital for designing dams and drainage systems. Engineers must calculate the seepage velocity and pressure to prevent "piping" or internal erosion that could lead to structural failure.

τ = c + σ' tan(φ)