Abstract: A system for placing instrumentation within a hole enables a wide variety of instruments to be placed in the hole with enhanced measurement resolution and minimum risk of becoming lodged in the hole by partial collapse of the hole wall. A flexible tubular member is pressurized and averted from a canister into the hole, turning inside out as it extends into the hole. The application of pressure urges the tubular member against the hole wall in the manner of a hole liner or packer. A wide variety of instruments can be attached to the membrane and urged against the hole wall for measurement purposes. Typical measurements include temperature, pore fluid extraction and injection, in situ sensing with fiber optics, pore fluid pressure, and the like.

Abstract: This invention is a stress gauge whose components include a piezoresistive sensor embedded in epoxy, a flatjack, and a housing for the sensor and flatjack. The preferred piezoresistive sensor is ytterbium because of its sensitivity to pressures in the range of interest. This arrangement allows the gauge sensing element to be calibrated at the place of measurement. That calibration is provided by a well controlled uniaxial load applied to the gauge to test the gauge response. Upon removal of the applied load, the gauge can continue to measure the stress history of the surrounding medium.