深部高强锚注切顶自成巷方法与验证

针对深部高应力回采巷道围岩控制难题,以我国最大采深矿井——山东泰安孙村煤矿为工程背景,对传统沿空掘巷、锚杆(索)支护巷道进行监测分析,结果表明:巷道围岩变形量大,破坏范围广,锚杆大部分处于强度劣化区内,难以发挥支护作用,锚索受力大,接近极限破断力。为解决上述问题,系统开展了不同煤柱宽度、地应力大小、顶板围岩强度、切顶高度等影响因素下的数值试验研究,建立了顶板应力释放率、侧向支承压力提升率与围岩变形控制率等定量评价指标,对比分析了多种因素下切顶自成巷与沿空掘巷矿压变化规律与围岩控制机制。基于此,提出了深部高强锚注切顶自成巷方法,利用高强锚注提高巷道顶板完整性,利用顶板预裂切缝切断采空区与巷道顶板之间的应力传递,使巷道处于应力降低区。为进一步验证该方法的合理性,利用自主研发的地质力学模型试验系统,开展了模型试验对比研究,高强锚注切顶自成巷围岩应力比沿空掘巷平均降低20.8%,围岩变形量为后者的45.1%,应力释放与围岩控制效果明显。结合上述研究,提出了相应的工程建议,并在孙村煤矿2215工作面进行了现场应用,监测表明该方法有效控制了巷道围岩变形,实现了无煤柱开采。

Automatic roadway formation method by roof cutting with high strength bolt-grouting in deep coal mine and its validation

Surrounding rock control is a big challenge in high stress mining roadway of deep coal mine.To address this issue,Suncun Coal Mine,the coal mine with the largest mining depth in China,is taken as engineering background to monitor and analyze the traditional gob-side entry driving with bolt and cable supporting.The result shows that the surrounding rock deformation is large and the surrounding rock damage scope is wide.Most of the bolt body is in the strength degradation zone,which makes it difficult to play its bolting role.The stress of anchor cable is large,which is close to the ultimate bearing capacity of the anchor cable.For the above problems,the numerical tests of different pillar width,in-situ stress level,strength of roof surrounding rock and roof cutting height were systematically carried out.The quantitative evaluation indexes such as roof stress release rate,side abutment pressure increase rate and surrounding rock deformation control rate were established.The variation law of mining pressure and the surrounding rock control mechanism in both the automatically formed roadway by roof cutting and traditional gob-side entry driving under various factors were compared and analyzed.On this basis,the automatic roadway formation method by roof cutting with high strength bolt-grouting in deep coal mine was proposed.This method improves the integrity of the roof surrounding rock by high strength bolt-grouting and cuts off the stress transfer between the goaf roof and roadway by roof pre-splitting crack,making the roadway in the stress reduction zone.In order to validate the rationality of this method,a model test was carried out by using the geomechanical model test system independently developed.The average stress of surrounding rock in automatically formed roadway by roof cutting with high strength bolt-grouting is 20.8%lower than that in gob-side entry driving,and the surrounding rock deformation is 45.1%of that in gob-side entry driving.The effect of stress release and surrounding rock control in automatically formed roadway by roof cutting with high strength bolt-grouting is obvious.Based on the above research,the corresponding engineering recommendations were put forward and the method was applied to the 2215 working face of Suncun Coal Mine.The field application and monitoring show that the method can effectively control the deformation of surrounding rock and achieve coal mining with no-pillar.