Determining required underpressure for causing ground water table to settle - extracting soil sample and deriving soil transmissivity to air phase, using direct relationship between relative air-water transmissivity and saturation potential function

摘要

A method of determining the required underpressure for causing ground water to settle in a needle filter under vacuum involves extraction of soil samples and deriving the soil transmissivity to the air phase from a product of a local transmissivity coefficient and a reduction factor using a given equation. The required underpressure is then derived graphically from a direct relationship between the relative transmissivities for water and air and a saturation potential function. USE -Water removal from ground on which ground work or construction work is to be conducted. Fitting needle filter pipe for use as fountain.