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Water is drawn into a small tube by surface tension. Water pressure, u, is negative above and positive below the free water surface. If there is no pore water flow occurring in the soil, the pore water pressures will be hydrostatic. The water table is located at the depth where the water pressure is equal to the atmospheric pressure. For ...
Shear strength is a term used in soil mechanics to describe the magnitude of the shear stress that a soil can sustain. The shear resistance of soil is a result of friction and interlocking of particles, and possibly cementation or bonding of particle contacts. Due to interlocking, particulate material may expand or contract in volume as it is ...
Residuum (geology) Residuum is weathered rock that is not transported by erosion, contributing in time to the formation of soil. It is distinguished from other types of parent material in that it is composed solely of mineral, not organic, material, and it remains in place rather than being moved by the action of wind, water, or gravity.
Geothermal gradient is the rate of change in temperature with respect to increasing depth in Earth 's interior. As a general rule, the crust temperature rises with depth due to the heat flow from the much hotter mantle; away from tectonic plate boundaries, temperature rises in about 25–30 °C/km (72–87 °F/mi) of depth near the surface in ...
A direct shear test is a laboratory or field test used by geotechnical engineers to measure the shear strength properties of soil [1][2] or rock [2] material, or of discontinuities in soil or rock masses. [2][3] The U.S. and U.K. standards defining how the test should be performed are ASTM D 3080, AASHTO T236 and BS 1377-7:1990, respectively.
Bearing capacity. In geotechnical engineering, bearing capacity is the capacity of soil to support the loads applied to the ground. The bearing capacity of soil is the maximum average contact pressure between the foundation and the soil which should not produce shear failure in the soil. Ultimate bearing capacity is the theoretical maximum ...
Pore water pressure (sometimes abbreviated to pwp) refers to the pressure of groundwater held within a soil or rock, in gaps between particles (pores). Pore water pressures below the phreatic level of the groundwater are measured with piezometers. The vertical pore water pressure distribution in aquifers can generally be assumed to be close to ...
Water retention curve is the relationship between the water content, θ, and the soil water potential, ψ. This curve is characteristic for different types of soil, and is also called the soil moisture characteristic. It is used to predict the soil water storage, water supply to the plants (field capacity) and soil aggregate stability.