Development of Soil Pressure Gages

摘要

This report describes a soil pressure measuring system which involves quick-freezing a zone of soil in the 'free-field,' excavating a cavity in the frozen zone, suspending a triaxially sensitive pressure gage in the cavity, and surrounding the gage with a liquid which changes to an elastic solid before the solid thaws. An auxiliary procedure is determination of insitu soil stress-strain properties in thawed cavities carved from frozen zones surrounding the point at which future pressure measurement will be made. A triaxially sensitive spherical gage was developed and tested. Equipment for freezing a zone of soil was tested, and a cavity trimming tool was successfully used. Suitable room-temperature-vulcanizing silicone rubber compounds were formulated which would solidify in the frozen environment. A concept was developed, but not tested, for a device to perform the auxiliary determination of soil stress-strain properties. Also included in the report is a brief review of soil pressure measurement techniques. (Author)