PIEZORESISTIVE SOIL STRESS GAGES
Technical Report,01 Oct 1964,31 Jan 1966
IIT RESEARCH INST CHICAGO IL CHICAGO United States
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A study was conducted to review the characteristics of available piezoresistive materials and evaluate their suitability as transducers for soil stress gages. The scope was limited to gages for measuring one component of static and dynamic free-field stresses. Three concepts were considered theoretically 1 piezoresistive strain gage elements mounted on a deflecting diaphragm, 2 solid piezoresistive elements in direct compression and 3 solid piezoresistive beam elements subjected to bending. Gages were designed and fabricated to test each of these concepts. The most satisfactory overall results were obtained with the diaphragm gage. Four such gages were delivered to AFWL in fulfillment of the contract requirements. The compression gage has merit, but there remain many fabrication problems to be overcome. Further effort will be required to develop this concept. A systematic study of the behavior of diaphragm gages in soil is one of the most important activities which needs to be undertaken.
- Soil Mechanics