深部沿空留巷围岩变形特征与支护技术

DEFORMATION CHARACTERISTICS OF SURROUNDING ROCK AND SUPPORTING TECHNOLOGY OF GOB-SIDE ENTRY RETAINING IN DEEP COAL MINE

以淮南谢家集第一煤矿深部沿空留巷为工程背景,采用数值模拟分析巷道围岩变形与应力分布特征。详细介绍深部沿空留巷井下试验,包括巷内基本支护、加强支护与巷旁支护设计,从巷道掘进、留巷,一直到留巷复用各阶段的矿压监测数据。通过围岩、充填体位移与锚杆、锚索受力数据分析,评价支护效果。井下实践表明:采用高预应力、强力锚杆与锚索作为巷内基本支护,单体支柱配铰接顶梁为加强支护,及膏体充填巷旁支护,能够有效控制深部沿空留巷围岩的强烈变形,保持留巷稳定。基于数值模拟与井下试验研究成果,分析巷内基本支护、加强支护与巷旁支护的相互关系,指出深部沿空留巷在顶板断裂位置、基本顶回转及围岩长期蠕变等方面与浅部留巷有很大区别,并提出深部沿空留巷支护设计原则。针对井下试验中存在的问题,提出改进意见。

Deformation characteristics of surrounding rock and stress distribution of deep gob-side entry retaining,which was located in the first coal mine of Xiejiaji,the Huainan coal mining area,were analyzed by means of numerical simulation.The underground test for the deep gob-side entry retaining was introduced in detail,including the designs for primary supporting in the entry,additional enhanced supporting,and supporting beside the entry,and the monitoring data during various stages from driving,retaining to reusing.The supporting effects were evaluated through the analysis of the data of surrounding rock and backfilling body displacements and the loads along bolts and cables.The underground practice points out that the severe surrounding rock deformation in the deep gob-side entry retaining can be effectively controlled;and its stability can be kept by means of the synthetic supporting system,which consists of the high pretension and intensive bolts and cables as the primary supporting in the entry,individual props with articulated roof beam as the enhanced supporting,and paste backfilling as supporting beside the entry.On the basis of the research achievements obtained from numerical simulation and field test,the relationship between the primary supporting in the entry,additional enhanced supporting and supporting beside the entry were discussed;the great differences between deep and shallow entries on the breaking position of main roof,its rotation,and long-term creep of surrounding rock were indicated;and the supporting design criteria for the deep gob-side entry retaining were put forward.The improvement suggestions were also made in accordance with the existing problems in underground test.