TESTING METHOD FOR WATER PERMEABILITY IN FIELD

摘要

PURPOSE:To eliminate the needs for pumping up the ground water in a pit by closing the tip of a measuring tube with a trip valve and by sealing the space between the pit wall and the measuring tube by expanding a packer. CONSTITUTION:A pit 1 is bored. A measuring tube 3 whose top 3a is provided with an enclosed trip valve 4 and a packer 5 is inserted from its tip 3a into the test layer level 2 composed of a sandy water permeable soil layer of the pit 1. Then, the packer 5 is expanded through an air supply pipe 7 leading to a gas container so as to set the measuring tube to the wall of the pit, whereupon the flow of the ground water 9 in the test layer level and also of the ground water 8 in the other layer level is interruped. When the trip valve 4 is set to an open state 4', the ground water 2 goes up until being equilibrated through varying water levels 10 (So...St) inside the measuring tube 3. The relation between the water levels 10 and time is measured to obtain a water permeation coefficient.