Definition - What does Strain Gauge mean?
A strain gauge is a device that measures the strain a material experiences when force or pressure is applied. Strain gauges can be mechanical or electrical resistance strain gauges. They are used to measure the in-situ stress based on stress release around the borehole after overcoring.
Trenchless methods require boring under the earth surface with the presence of overburden pressure and stresses within rock masses. It is necessary to determine the bearable strain in order to use correct methods, equipment and materials for boring and installation.
Trenchlesspedia explains Strain Gauge
A strain gauge is used in testing methods such as the flat jack test and overcoring. It measures the acting stresses or mechanical parameters of structures. During excavation, in-situ stresses can be released causing rock burst, buckling and other ground control problems. The test is based on the stress release in a small area of a structure by cutting a plane perpendicular to the surface. It is also used for determining radial displacement in boreholes.
Radial displacement is recorded by the strain gauge and used for estimating stress for various geological conditions. During excavation, in-situ stresses can be released causing rock burst, buckling and other ground control problems.