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

采用美国矿务局卢平辉博士研制的由一套液压钻孔压力传感器和液压压力计、液压泵组成的软岩地压测量系统进行了现场试验。井中压力传感器由一个圆柱形压力传感器（CPC）和两个平板式压力传感器（BPC）组成。在第一年，这些压力电池的物理和机械性能进行了测量，并通过这些测量重新安排的属性。第二年，在地下采场岩柱（火山凝灰岩，覆岩= 120m）和某煤矿地下巷道工作面（壳体，覆岩= 600m）两个岩体现场进行了矿压实测，实测矿压与理论计算值基本一致。但是，当钻孔内壁因岩体中存在大小不等的裂隙而不光滑时，在钻孔中插入压力盒的工作会遇到一些麻烦。

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.