深部巷道钻孔卸压机理与围岩稳定控制研究

Pressure relief of roadway has the advantages of transferring high stress and improvement of roadway conditions. But due to pressure relief being disturbance and damage to the opened coal and rock mass, degree of pressure relief and supporting opportunity and other factors can significantly affect roadway(especially the roadway buried deeply) stability subjected to pressure relief, reasonable control degree of pressure relief and development of the corresponding supporting techology was the key to solve the supporting puzzle of deep roadway used the pressure relief technology.Thence, this project will carry out some researches as follows:(1) based on the coal and rock mass post-peak mechanical behaviors, the evolution characteristics of stress field and strength weakening rules of deep pressure drilling relief roadway will be revealed, which provides the basic idea for studying the mechanism of deep roadway after pressure relieved;(2)by analysing the dynamic mechanism of pressure relief in the deep roadway, the proper drilling relief parameters and applicable conditions will be determined and the pressure relieving mechanism will be revealed;and (3) by establishment rheological-damage mechanics model of supporting structure characterised by bolting and grouting in drilling relief roadway buried deep, the timeliness and periodic stability controlling mechanism of interaction of pressure relief and supporting structure of bolting and grouting will be revealed, proper relief extent and relevant controlling technique and judging criteria of chance will be determined. It provides a basis for 'pressure relieving and supporting of surrounding rock' of deep roadways.

钻孔卸压具有转移高应力、改善巷道维护状况、施工方便等优点，但该方法的应用会再次扰动、弱化开挖卸荷后的煤岩体结构，巷道（尤其深部巷道）维护难易与卸压程度、支护时机等因素密切相关，合理控制卸压程度、开发相应控制技术是应用钻孔卸压解决深部巷道支护难题的关键。为此，本课题主要开展以下内容研究：（1）研究钻孔卸压煤岩体峰后损伤力学特性，揭示深部钻孔卸压巷道应力场演化特征与强度损伤规律，为研究深部巷道钻孔卸压机理提供依据。（2）分析钻孔卸压对深部巷道围岩稳定的动态作用机理，确定深部巷道合理的钻孔卸压参数和适用条件，揭示深部巷道钻孔卸压机理。（3）建立深部钻孔卸压巷道锚注支护结构的流变-损伤力学模型，揭示钻孔卸压与锚注支护结构相互作用的时效性与稳定控制机理，确定合理卸压程度、相应动态控制技术和时机，为研究深部巷道"围岩钻孔卸压-支护"方法提供依据。

深部高应力巷道围岩稳定控制问题严重影响着深部煤炭资源的安全高效开采，卸压技术是控制该类巷道围岩大变形的有效方法之一，但其缺乏完整的技术体系。本文综合运用室内试验、理论计算、数值模拟及现场工业性试验等方法，系统研究了深部巷道钻孔卸压机理与围岩稳定控制技术，取得如下研究成果：.（1）采用室内加卸载试验的方法，将岩样加载至峰后应变软化段各目标点后卸载，获取了不同损伤程度的初始损伤岩样，采用多级围压多次峰值屈服试验方法测定了初始损伤岩样的力学参数，选取塑性剪切应变 表征岩样的损伤变量，拟合得到 与损伤岩样强度参数的函数关系，初步建立了深部巷道围岩强度衰减模型。.（2）建立了围岩塑性扩容变形与卸压钻孔参数间的关系，并分析了卸压钻孔单孔作用范围，初步提出了卸压钻孔参数的理论确定依据。系统研究了卸压钻孔方位、卸压时机及钻孔参数（长度、直径和间排距）对深部巷道围岩稳定性的作用规律，提出了影响钻孔卸压效果的各因素的确定原则。.（3）分析了不同卸压程度下深部钻孔卸压巷道围岩的流变特征，研究了不同二次支护时机、二次锚注强度及范围对巷道围岩流变变形的控制效果，确定了试验巷道合理的二次锚注强度及范围。.（4）研究了卸压钻孔与巷道一次支护结构受力的相互作用关系，提出了深部巷道围岩“卸压-支护”控制技术体系。.（5）结合张双楼矿-1000m西大巷的生产地质条件，展开了现场工业性试验。现场应用表明，巷道采用“卸压-支护”技术后，可有效转移巷道围岩周边高应力，消除支护结构的非协调受力现象，促使支护结构与围岩形成统一、均衡的承载结构，共同抵抗围岩的剧烈变形，同时，该技术方案简单易行，可在类似条件下的深部巷道围岩控制领域推广应用。