On the Sensitivity of a Stressmeter Named Hydraulic Capsule

Abstract

A low modulus instrument named hydraulic capsule for monitoring stress changes in rock is described with particular reference to itss ensitivity. Me thod to estimate the stressc hange in rock from the recorded pressure change has been proposed based on the two dimensional elasticm odel: Knowing the rock stiffnesas nd the length of the tubing, the pressurec hange can be easilyc onverted to the change of rock stressu sing Eq. 3 with an aid of two graphs as shown in Figs.9 and 10.
Its correctness has been verified in the laboratory study for several types of materials