Engineering study on fracturing high-level hard rock strata by ground hydraulic action
Engineering study on fracturing high-level hard rock strata by ground hydraulic action
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地面水力作用压裂高层硬岩地层工程研究
DOI：
10.1016/j.tust.2019.01.019
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发表时间：
2019-04-01
影响因子：
6.9
通讯作者：
Meng, Xiangbin
中科院分区：
文献类型：
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作者：
Yu, Bin;Gao, Rui;Meng, Xiangbin
特厚煤层的地下开采引起上覆岩层的大量迁移，并产生极大的地压。针对高位硬岩层破碎失稳产生的强大地压及其抑制困难，提出了地面水力压裂（GHF）破断高位硬岩层的创新方案。以大同塔山煤矿20 m厚煤层为例，进行了高位硬岩层的现场水力作用试验。通过现场测量确定了水力压裂的关键层（KS），并选择KS 3和KS 4作为目标层，分别位于煤层垂直上方110 m和145 m处。然后使用垂直威尔斯井进行压裂。微地震测量表明，KS 3的水力裂缝长250 m，而KS 4的水力裂缝长218 m。裂缝区宽度为30-120 m。KS 3和KS 4中的水力裂缝呈现交错图案，增强了压裂效果。地表水力作用改变了高位岩层的裂隙结构，从而缓解了工作面周围的应力集中。压裂后工作面未出现强烈矿压显现。支架受力明显减小，超前巷道变形得到控制。这是第一次现场GHF实验，以控制强岩层行为是成功的，铺平了道路的新的可能性，高层次的硬岩层控制安全开采。
The underground mining of extra-thick coal seams causes substantial migration of the overburden and generates extreme ground pressures. In view of the strong ground pressures produced by breakages and instabilities in high-level hard strata and the difficulties in their containment, we proposed an innovative solution to fracture high-level hard strata by ground hydraulic fracturing (GHF). Taking a 20 m thick coal seam in Tashan coal mine (Datong mine area, China) as an example, in situ ground hydraulic action experiments on the high-level hard rock strata was performed. In-situ measurements was performed to determine the key strata (KS) to be hydraulic fractured, and KS3 and KS4 were selected to be the target strata which were 110 m and 145 m away vertically above the coal seam, respectively. Fracturing was then performed using vertical wells. Micro-seismic measurements showed that the hydraulic fissure in KS3 is 250 m long, whereas 218 m in KS4. The fractured regions are 30-120 m in width. The hydraulic fissures in KS3 and KS4 exhibit an interlaced pattern that enhances the fracturing effect. Ground hydraulic action changed the fracturing structures of the high-level rock strata, thereby relieving the stress concentration around the working face. No strong strata behavior was observed on the working face after fracturing. The forces exerted on the supports was significantly reduced and the deformation of advanced roadways was controlled. This first-time field GHF experiment to control the strong strata behavior was successful, paving the way for new possibilities to high-level hard strata control for safety mining.