沿空留巷超前预裂卸压机理及预裂钻孔布置原则  

Mechanism of pressure relief by advanced pre-splitting in gob-side entry retaining and arrangement principle of pre-splitting boreholes

作　　者：王晓卿 WANG Xiaoqing(CCTEG Coal Mining Research Institute,Beijing 100013,China;Coal Mining Branch,China Coal Research Institute,Beijing 100013,China;State Key Laboratory of Intelligent Coal Mining and Strata Control,Beijing 100013,China)

机构地区：[1]中煤科工开采研究院有限公司,北京100013 [2]煤炭科学研究总院开采研究分院,北京100013 [3]煤炭智能开采与岩层控制全国重点实验室,北京100013

出　　处：《采矿与安全工程学报》2024年第6期1125-1133,共9页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(52274124,52274123);天地科技股份有限公司资助项目(2022-2-TD-QN008)。

摘　　要：为阐明沿空留巷超前预裂卸压机理并指导预裂钻孔布置,建立混凝土支柱沿空留巷卸压数值模型,模拟分析预裂角度和预裂高度对留巷围岩应力与支柱顶面压缩量的影响规律,证实工作面超前预裂对沿空留巷具有卸压减沉效果,揭示沿空留巷超前预裂卸压机理,提出预裂钻孔布置原则,并进行工程验证。研究结果表明:工作面超前预裂对沿空留巷具有显著的卸压减沉效果,卸压效果主要体现在降低留巷周边围岩的应力集中;工作面超前预裂通过人工制造预裂带切断留巷上方侧向悬顶内的厚层坚硬顶板,从而切断采空区上部覆岩载荷传递路径,减小侧向悬顶对留巷的施压,实现留巷卸压;留巷卸压减沉效果与预裂角度或预裂高度之间具有正相关性。预裂钻孔倾角应尽可能大,预裂钻孔长度应使钻孔尽可能多地穿越厚层坚硬顶板,至少应高出垮落带上方第1个基本顶;何家塔煤矿50108工作面采用混凝土支柱沿空留巷技术回采,预裂钻孔倾角为80°,预裂钻孔垂深为29.0 m,超过第2个基本顶,端头支架平均压力相比无预裂降低29%,卸压效果显著,留巷效果较好。In the hope of clarifying the mechanism of pressure relief by advanced pre-splitting in gob-side entry retaining and elucidating the arrangement principle of pre-splitting boreholes,a numerical model for pressure relief in gob-side entry retaining with concrete columns as roadside support was established.With this model,the influences of pre-splitting angle and pre-splitting height on the stress in surrounding rock of retained roadway and the compression amount on the top surface of columns were analyzed by simulation.The analysis confirmed the pressure relief and subsidence reduction effects of advanced pre-splitting on the retained roadway.On this basis,the pressure relief mechanism of advanced pre-splitting in gob-side entry retaining was revealed,and the arrangement principle of pre-splitting boreholes was proposed,which were then verified in engineering applications.The results show that advanced pre-splitting has significant pressure relief and subsidence reduction effects on the retained roadway.The pressure relief effect is mainly reflected in alleviating the stress concentration of surrounding rock around the retained roadway.A pre-splitting zone is artificially created by means of advanced pre-splitting to cut off the thick and hard roof inside the lateral overhanging roof above the retained roadway,thus cutting off transmission paths of the load from the overburden above the goaf and reducing the pressure exerted by the lateral overhanging roof on the retained roadway.As a result,pressure relief is achieved in the retained roadway.Moreover,the pressure relief and subsidence reduction effects are positively correlated with the pre-splitting angle and the pre-splitting height.The inclination angle of pre-splitting boreholes should be as large as possible,and their length is supposed to be large enough,at least higher than the first main roof above the caving zone,to penetrate the thick and hard roof to the full.The 50108 mining face in Hejiata Coal Mine is recovered by gob-side entry retaining with concr

关 键 词：沿空留巷 工作面超前预裂 预裂钻孔 卸压 数值模拟 

分 类 号：TD322[矿业工程—矿井建设]