深部巷道巷内卸压能量耗散与调控机理研究

Pressure-relief treatment (drilling, notching, lancing, etc.) implemented in roadway shifts the high stress near the roadway to deeper rock mass but leads to a damage to the surrounding rocks of roadway. Since the support suppresses the surrounding rock damage and energy dissipation resulting from pressure-relief treatment, roadway stability is determined by the joint influence of pressure relief and support. Investigating the coupling effect between pressure relief and support in terms of energy dissipation and developing corresponding control technique is one of the effective methods of solving the support problem for deep roadway. In this paper, the relevant research has been conducted by using indoor experiment, analytical analysis and numerical simulation, including following aspects: 1) a constitutive model for rock with damage based on energy dissipation is developed and impact of pressure-relief on energy dissipation and roadway stability is investigated, which exposes the mechanism of secondary damage of surrounding rocks of roadway due to pressure relief; 2) a coupled model for support structure and energy dissipation is constructed and the influence of support on the pressure relief is studied. The coupling effect between energy field and support is investigated by considering the three key factors including pressure relief, support and surrounding rocks, which exposes the mechanism of coupling between “pressure relief-support” and surrounding rock stability; 3) the pressure-relief support control technique is developed based on the aforementioned results, which improves the stability of surrounding rocks for deep roadway.

巷内卸压（钻孔、开槽、切缝等）在转移高应力的同时，损伤了开挖卸荷后围岩强度，加剧了围岩能量耗散，而支护对卸压诱发的围岩破坏及能量耗散具有抑制作用，卸压巷道稳定状态受卸压与支护共同影响，从能量耗散角度研究“卸压-支护”控制围岩稳定的耦合效应，开发相应控制技术是解决深部巷道支护难题的有效方法之一。为此，本课题采用室内试验、理论分析、数值模拟和工业性试验等方法，展开以下研究：1）建立基于能量耗散的煤岩体损伤本构模型，研究卸压对巷道围岩能量耗散及其稳定状态的扰动规律，揭示卸压诱发巷道围岩二次破坏的机理；2）建立卸压巷道支护结构与能量耗散的耦合分析模型，探究支护对卸压围岩能量耗散的调控关系，从卸压、支护与围岩三要素出发，研究能量场与支护场控制围岩稳定的耦合效应，揭示“卸压-支护”与围岩稳定的耦合作用机理；3）结合上述研究内容，开发“巷内卸压-支护”协调控制技术，为深部巷道围岩稳定控制提供技术保障。

本项目综合采用室内试验、理论分析、数值模拟和工业性试验等方法，建立了基于能量耗散的煤岩体损伤本构模型，研究了卸压对巷道围岩能量耗散及其稳定状态的扰动规律，揭示了卸压诱发巷道围岩二次破坏的机理；其次，建立了卸压巷道支护结构与能量耗散的耦合分析模型，从卸压、支护与围岩三要素出发，研究了能量场与支护场控制围岩稳定的耦合效应，揭示了“卸压-支护”与围岩稳定的耦合作用机理，开发了“巷内卸压-支护”协调控制技术，为深部巷道围岩稳定控制提供技术保障。.经过课题组研究人员三年来不懈的努力，本项目基本取得了预期的科研成果，共发表学术论文15篇，其中，SCI收录6篇，EI收录4篇，项目负责人为第一发明人授权国家发明专利9项，获得省部级科研奖励7项，出版学术专著1部。取得的创新成果如下：.（1）推导了岩石能量计算有限差分方程式，采用FISH语言编制了能量耗散模型的有限差分程序，实现了对FLAC3D应变软化模型的二次开发，补充了软件能量计算模块。.（2）研究了钻孔卸压对深部巷道围岩的弱化效应，揭示了卸压诱发深部巷道二次破坏机理。巷道弱化程度与卸压程度正相关，卸压程度越大，巷道蠕变约严重，合理卸压程度是维护巷道稳定的前提条件。.（3）以钻孔直径和排距的比值（D/R）作为变量，研究了钻孔参数对卸压效果的影响规律。持续增加D/R，巷道由非充分卸压向过度卸压转变。合理D/R可保证巷道处于充分卸压状态，对于控制巷道变形有利。.（4）研究了锚杆支护对深部巷道围岩能量耗散及变形破坏的调控效应，锚杆预紧力、密度、长度以及锚固长度是调控围岩能量耗散的主控因素，合理支护参数可有效控制卸压巷道围岩发变形。.（5）揭示了锚注支护控制卸压巷道围岩稳定的作用机制，提出了支护时机、锚注强度及范围的确定方法，据此开发了深部巷道“卸压-支护”协调控制技术。