In Situ tests to Determine the Ground Pressure Existing in a Soft Rock Mass by Use of Hydraulic Borehole Cells.

采用美国矿务局陆培华博士研制的液压钻孔测压系统对软岩中存在的地压进行了现场测试，该系统由一套液压钻孔压力传感器和液压压力计、液压压力计组成。井筒压力室由一个圆柱型压力室(CPC)和两个平板式压力室(BPC)组成，为期两年。在第一年，测量了这些压力室的物理和机械性能，并通过这些测量重新安排了性能。第二年，对地下矿坑岩柱(火山凝灰岩，覆岩=120m)和煤矿地下巷道工作面(壳层，覆岩=600m)两个岩体场地进行了现场地压测量，实测地压与理论计算值基本一致。但是，当钻孔内壁因岩体中的大小裂隙而不平整时，在钻孔中插入压力计的工作就会遇到一些麻烦。

In situ tests are conducted for adopting the measuring system of ground pressure existing in a soft rock mass by use of hydraulic borehole cells, which had been developed by Dr.P.H.Lu in U.S.Bureau of Mines.This system is consisted from a set of hydraulic borehole pressure cells and hydraulic pressure gauge, hydraulic pressure pomp. And the borehole pressure cells are consisted from a cylindrical pressure cell (CPC) and two flat type pressure cells (BPC).This projects were held by two years. At the first year, physical and mechanical properties of these pressure cells were measured and the properties were re-arranged by these measurements. And at the second year, in situ measurement of ground pressure were conducted by two rock mass sites, the one was on an rock pillar in underground pit (volcanic tuff, covered rock = 120m), and the other was underground drift face of a coal mine (shell, covered rock = 600m).The measured ground pressures of these sites were nearly equal to calculated value of theoretically. But, there were some troubles on a working of inserting the pressure cells in the drilled borehole, when inner wall of the boreholes were not smooth by the large or small cracks in the rock mass.