超深矿井软岩裂隙-湿度-应力耦合蠕变破坏与高强控制机理研究

The creep damage of soft rock and the severe damage of roadway supporting system, with the increase of coal mining depth in China, occur frequently in deep soft rock mines, which makes the mines maintained again and again, forces the mines stop production and even stop construction. Developed fracture-high humidity-high stress coupling plays a critical role in the process of creep damage of deep-seated soft rock roadway, on the basis of whose geologic environment, thus high strength support and creep damage coupling mechanism need further study. Combined with such methods as experimental research, theoretical analysis, industrial field test and numerical simulation, the project obtains criterion which is based on the test of fractured mudstone upon humidity-mechanical coupling creep for identifying the occurrence of creep, the periodic transformation and the faster start. Based on mine rock mechanics, engineering geology, fractured rock mass damage mechanics, solid state thermodynamics and rheological mechanics theory, the mathematical model describing creep of deep soft rock with fracture-humidity-stress coupling is established and verified. Following a introduced discontinuous deformation theory, in pursuit of secondary development solution according to finite difference software, a comprehensive study is provided on fracture-humidity-stress coupling mechanism, on high strength supporting system in control of deep soft rock creep, on dynamic supporting theory and method of creep and high strength structure coupling mechanism about deep soft rock under the condition of complicated geology, high humidity and high stress, thus laying a theoretical foundation for roadway supporting , hazard prevention as well as high strength support design in the deep mines.

随着我国煤矿开采深度加大，软岩蠕变破坏与巷道支护系统严重破坏在深部矿井中频发，致使矿井反复维护、停产乃至停建。高发育裂隙、高湿度及高应力地质环境在深井巷道围岩蠕变破坏中起关键作用，高强控制与蠕变破坏耦合作用迫切需要深入研究。项目采用实验研究、理论分析、现场工业性试验和数值模拟的方法相结合，在对裂隙泥岩试件进行湿-力耦合蠕变试验基础上，确定深部软岩蠕变发生、阶段转化及加速启动判据；基于矿山岩体力学、工程地质学、裂隙岩体损伤力学、固体热力学及流变力学理论，建立和验证深部软岩裂隙-湿度-应力耦合蠕变数学模型；引入非连续变形理论，基于有限差分方法进行二次开发求解，揭示裂隙-湿度-应力耦合作用机理，提出控制深部软岩蠕变的超强支护结构系统，建立复杂地质、高湿度及高应力环境中深部软岩耦合蠕变与超强支护结构耦合作用的动态支护理论与支护方法，为超深部工程巷道支护、灾害防治及超强支护设计提供理论基础。

在深部开采过程中，面临岩体裂隙发育、高地应力和高水压等复杂环境，软岩的流变现象更加突出，随时间会产生较大的蠕变变形，给矿山井巷工程掘进与支护带来了极大挑战。项目在对煤矿典型软岩基本物理力学特性进行试验研究的基础上，采用室内试验、模型试验、理论分析、数值模拟和现场工业性试验相结合的研究方法，研制了弱胶结裂隙砾岩、砂岩和泥质粉砂岩的相似模型材料并制备了大量裂隙岩样，针对弱胶结裂隙砾岩、砂岩和泥质粉砂岩在渗流-应力耦合作用下开展了大量卸围压蠕变试验，系统分析了应力、渗流（湿度、渗透压）和裂隙分布与发育程度对蠕变曲线类型及蠕变发展规律的影响。结合裂隙砾岩、粉砂岩流变曲线特征的综合分析，采用能表述裂隙软岩渗流-应力耦合特征的流变模型对试验结果进行了参数识别；结合裂隙砂岩的蠕变试验曲线，基于分数阶微积分理论和试验结果，采用H体、Abel黏壶、C|Abel黏壶串联的四元件模型模拟弱胶结砂岩蠕变特性，并通过引入损伤因子，建立了裂隙砂岩新型分数阶损伤本构模型。基于超深矿井软岩流变特征，研制了一种内嵌式托盘结构的高强锚杆（索）和一种施加高强预紧力装置，能有效控制超深矿井软岩的大变形；设计了一种新型套管膨胀式让压锚杆，可有效提供恒阻让压功能，对超深矿井软岩大变形具有较好的适应性；研发了一种凝结时间可调控的新型水泥聚氨酯锚固材料，在实现锚杆（索）全长锚固的同时，还可有效填充岩体中的细小裂隙和加固围岩。在“裂隙-渗流-应力”耦合作用下软岩流变理论与试验研究的基础上，结合红庆梁煤矿弱胶结砂岩的工程地质特点进行现场工业性试验。试验结果表明，项目提出的裂隙软岩流变本构模型能够较好的描述裂隙软岩在渗流-应力耦合作用下的蠕变行为，为解决超深矿井软岩巷道支护设计提供了可靠的基础理论；研发的内嵌式大托盘、高强锚杆和新型锚固材料为解决超深矿井软岩巷道支护提供了新方法，具有广泛的推广应用前景。