WebAug 25, 1976 · A non-dimensional set of results is given which enables one to use the jack with confidence, in rocks of various stiffnesses. N. Current techniques to measure the deformability of rocks in place are the plate bearing test (references 1,3,6,16,22), the borehole jack test (7,10,11,12,15), the flat jack test (1), and the dilatometer test (7,18,21). WebSpecimens are placed in a triaxial cell and subjected to the predetermined stress condition in terms of confining pressure (related to uniform horizontal stress), vertical stress (over-burden stress) and pore pressure. Injecting a constant flow rate into the cavity hole pressurizes the specimen.
Suggested method for deformability determination using a large flat …
WebThe test is performed by making a cut to a uniform depth into the mortar courses and inserting the flat jack or couple of jacks, which are pressurized to the desired level. Test … WebSep 1, 2015 · The Flat Jack method is a “cancellation” in-situ stress test method, in which a thin slot is cut into the rock surrounding an underground opening and a pressure gage is inserted into the slot (Fig. 1a). The pressure in the flat jack is increased until the recorded strain relaxation of the sidewall is cancelled (Fig. 1b). polygon eight sides
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WebDec 10, 2016 · This test is intended to measure in situ deformability of rock mass by inserting flat jacks into slots cut into rock using a rock saw or a series of overlapping drilled holes (Loureiro-Pinto 1986) (Figs. 2 and 3 ). The test can be performed on up to four coplanar slots simultaneously. WebNov 20, 2012 · After 4 months, the flat jack test results are within the stress range determined with the strain gauges. On the contrary, after 2 years the stress values estimated on the basis of strain gauge measurements are considered to be an upper bound to the state of stress in the concrete lining and the stress relief tests may be reasonably considered ... WebThe Flat Jack method is a “cancellation” in-situ stress test method, in which a thin slot is cut into the rock surrounding an underground opening and a pressure gage is inserted into … polygon electric folding bike