Abstract

Pressuremeter is a cylindrical probe that has an expandable flexible membrane designed to apply a uniform pressure to the wall of a borehole. Various pressuremeters are widely used to measure soil properties, such as stiffness, strength, horizontal pressure etc. It has been becoming a concern that the drilling process which conveys the pressuremeter instrument to the certain depth would seriously affect the results of pressuremter tests.

In this talk a series of drilling disturbance will be identified. Strain Path Method and Cavity Expansion Theory will be applied to investigate the magnitude of the drilling disturbance. There are two soil models used in this project for pressuremeter tests in undrained and drained conditions. A newly-developed experimental instrument which measures the pore pressure change at various positions on the instrument during the drilling process will be also introduced so that the simulation results can compared with. Once the disturbance effect is identified and quantified, new analytical and numerical method to improve the measuring accuracy of pressuremeter will be presented.