基于围岩松动圈数值模拟的穿层钻孔测压结果分析

Results Analysis of Pressure Testing for Through Beds Hole Based on Numerical Modeling of Surrounding Rock Loose Circle

针对试验矿井穿岩钻孔测压结果严重偏低的现象,采用Comsol Multiphysic软件对试验矿井测压地点围岩的塑性区进行了模拟,结果表明当巷道距煤层最短距离小于7 m时,围岩松动圈裂隙已与煤层贯通。此种情况下,常规的水泥砂浆封孔不能满足测压封孔要求,松动圈内围岩裂隙与测压气室沟通泄压是导致测压结果偏低的主要原因,此时应选用"两堵一注"带压封孔方法,且封孔压力不小于6 MPa。

According to the fact that the measuring pressure in the test mines by cross rock drilling is much lower than its adjacent mine,a numerical simulation is applied to analyze surrounding rock plastic zone in test site by Comsol Multiphysic software. The results show that when the shortest distance of the roadway is less than 7 m from the seam,the surrounding rock loose circle has been passed through the seam. In the case,it can not meet the requirements by use of conventional cement mortar sealing under pressure,and the main reason caused the lower pressure test results is decompression of the cracks passing through surrounding rock loose circle and the pressure chamber. So we should choose the pressure sealing method of ＂ two ends blocking and middle injection＂,and the injection pressure must be more than 6 MPa.