porevannstrykk

Porevannstrykk, also known as pore water pressure or pore pressure, is the pressure of groundwater held within the pores or voids of a soil or rock mass. It is a crucial parameter in geotechnical engineering and hydrology, significantly influencing the mechanical behavior of soil and rock. When water is present in the pore spaces, it exerts a pressure that pushes the soil or rock particles apart. This pore water pressure acts independently of the total stress, which is the sum of the stresses on the soil skeleton and the pore water.

The effective stress, a fundamental concept in soil mechanics, is defined as the total stress minus the pore water pressure. It is the effective stress that governs the strength and deformation characteristics of the soil. High pore water pressure reduces the effective stress, leading to a decrease in shear strength. This phenomenon is particularly relevant in slope stability analysis, where increased pore water pressure due to rainfall or other sources can lead to landslides. Similarly, it plays a role in the bearing capacity of foundations and the stability of excavations.

Measuring pore water pressure typically involves installing piezometers, which are instruments designed to detect and record the pressure of groundwater. Understanding and accurately determining pore water pressure is essential for the safe and efficient design of numerous civil engineering projects, including dams, tunnels, and retaining walls. Variations in pore water pressure can be influenced by factors such as rainfall, snowmelt, pumping operations, and geological conditions.