煤柱留巷定向水力压裂卸压机理及试验

发布时间：2018-10-16 14:41

【摘要】：针对煤柱留巷支护问题,提出一种控制坚硬厚顶板煤柱留巷变形的新方法——定向水力压裂留巷卸压技术,旨在转移护巷煤柱上的高采动应力,改善留巷的应力状态,并提出定向水力压裂煤柱留巷卸压机理。以余吾煤业公司S1206煤柱留巷瓦排巷为研究对象,确定了定向水力压裂钻孔方案、钻孔布置参数及施工工艺。压裂结果显示,横向切槽机械钻头可以在预定位置预制开槽;21~28 m分段压裂时间占总压裂时间48%,是整个钻孔的压裂关键位置;采用间接方法判断裂隙的扩展范围20 m左右。对压裂段和非压裂段进行了表面位移、煤柱垂直应力、工作面超前支承压力、压裂段煤柱上方三向应力等监测。监测结果表明:压裂段两帮收缩量降低30.5%,顶底板移近量降低50.2%;超前压力的影响距离不超过50 m,距离工作面超过15 m左右时,出现应力峰值;超前工作面10 m左右范围内出现塑性破坏;采动影响最显著的作用来自垂直应力;采空区造成应力扰动方向与最大相对主应力方向一致。监测与评估表明卸压效果明显。压裂及卸压结果表明,采用定向水力压裂留巷卸压技术可以消除或减弱坚硬顶板形成的悬顶效应,达到留巷的目的。
[Abstract]:In view of the problem of retaining roadway support with coal pillar, a new method to control the deformation of retaining roadway with hard and thick roof coal pillar, i.e. directional hydraulic fracturing, is put forward, which aims at transferring the high mining dynamic stress on the pillar of protecting roadway and improving the stress state of retaining roadway. The pressure relief mechanism of directional hydraulic fracturing coal pillar in roadway is put forward. Taking S1206 coal pillar of Yuwu Coal Industry Company as the research object, the drilling plan, drilling layout parameters and construction technology of directional hydraulic fracturing are determined. The fracturing results show that the transverse slot cutting mechanical bit can be prefabricated and slotted at a predetermined position, the 2128 m fracturing time occupies 48% of the total fracturing time and is the key position of the whole drilling hole, and the extension range of the fracture is estimated by indirect method about 20 m. The surface displacement, vertical stress of coal pillar, leading supporting pressure of working face and three direction stress above the pillar of fracturing section were monitored. The monitoring results show that the shrinkage of the two sides of the fracturing section is reduced by 30.5, the movement of the top and bottom plate is reduced by 50.2, the influence distance of the leading pressure is not more than 50 m, and the stress peak occurs when the distance from the working face is more than 15 m. Plastic failure occurs in the range of 10 m or so in the leading working face; the most significant effect of mining action comes from vertical stress; the direction of stress disturbance caused by goaf is consistent with the direction of maximum relative principal stress. Monitoring and evaluation show that the effect of pressure relief is obvious. The results of fracturing and pressure relief show that the effect of suspended roof formed by hard roof can be eliminated or weakened by directional hydraulic fracturing in roadway and the purpose of retaining roadway can be achieved.
【作者单位】：煤炭科学研究总院开采研究分院;天地科技股份有限公司开采设计事业部;煤炭资源高效开采与洁净利用国家重点实验室;
【基金】：国家自然科学基金青年基金资助项目(51304119);国家自然科学基金煤炭联合基金资助项目(U1261211)
【分类号】：TD322.5

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