effective stress equation

Effective stress is a way to understand the actual pressure that influences how soil or rocks behave, especially when there's water present. It’s calculated by taking the total stress (the overall pressure from things pressing down) and subtracting the water pressure within the pores of the material. This difference tells us how much of the load is carried by the solid particles themselves, which is crucial for assessing stability and strength in geotechnical engineering. Essentially, effective stress shows the true force causing deformation or movement in underground materials.