煤层底板注浆加固效果波速探查与评价

The wave velocity detection and evaluation of the effect of grouting reinforcement in coal seam floor

底板注浆加固与含水层改造是承压水体上煤层安全开采底板岩溶水害防治的有效方法之一。为了评价煤层底板注浆加固效果,以皖北恒源煤矿Ⅱ615工作面为研究对象,采用钻孔震波检层法,选择正常区域和异常区域,分别对各区域注浆前后底板岩体进行了波速探测,结果表明:注浆前,正常、异常区域波速存在较大差异,注浆后两者基本一致;注浆后底板砂岩段岩层波速增加明显,约为注浆前的1.20倍,而海相泥岩段注浆前后波速变化不大,这与钻孔揭露岩芯的完整性和底板水无上升现象一致,充分说明注浆对裂隙岩体起到了很好的加固作用。

The grouting reinforcement of the coal seam floor and the construction of aquifers are effective methods in preventing and controlling of karstic water disaster in the coal seam floor above the confined aquifer during safe mining.In order to evaluate the effect of grouting reinforcement in the coal seam floor, the authors set the 11 615 working face of the Hengyuan coal mine in northern Anhui Province as the study object and selected normal regions as well as abnormal regions. In addition, wave velocity detection was conducted for floor rocks before and after grouting in each region respectively by logging with seismic wave in drill holes.The results show that there is a considerable difference in wave velocity between the normal and abnormal regions before grouting, and the wave velocities in the two regions are basically the same after grouting.The wave velocity of floor sandstone strata rises obviously after grouting and it is 1.2 times the wave velocity before grouting.However, the wave velocities of marine mudstone change only insignificantly before and after grouting, which is in accordance with the completeness of rock core and non-guide rise exposed by drill holes.All this fully indicates that grouting could play a good role in the reinforcement of crack rocks.