深井软岩温压耦合吸水软化流变特性及控制对策

For the bottleneck problem such as unclear rheological mechanism of soft rock after water softening and lack of effective control methods under the coupling effect of temperature - pressure in deep coal mine, taken a typical high temperature mine in deep underground as an engineering background, based on the adsorption law of gaseous water of soft rock under high temperature and high humidity environment, the rheological experiment system with high temperature which is the independent research and development is used to do the experiment. Rheological experiments is done with different absorption water stages (different moisture contents) under the coupling effect of temperature - pressure. Combined with variation characteristics of soft rock in microscopic fabric during the process of rheological experiments, from micro perspective to study macro rheological property, nonlinear variation law of soft rock with different moisture contents under the coupling effect of temperature - pressure is revealed. The temperature - pressure coupling rheological constitutive model considered softening damage after water absorption of soft rock is established, and a quick inversion analysis method to get mechanical parameters of soft rock under different conditions is set up. Based on iTOUGH2 platform which is a multi-field coupling numerical analysis system, the interface program for iTOUGH2 and FLAC3D will be developed to analyses the process of rheological failure of large deformation and its main controlling factors. Rheological interaction model of rock mass, based on the support of NPR cable/anchor which is constant resistance large deformation, is put forward, and NPR cable/anchor coupling control method for rheological large deformation of soft rock, based on deformation energy controlled, is formed. The experiment and analysis will provide control theory and technical support for the stability of deep soft rock roadways under high temperature and high humidity environment.

针对高温高压耦合作用下深井软岩吸水软化流变机理不清、缺乏有效控制方法等瓶颈难题，本项目以典型深部高温矿井为工程背景，在软岩与高温高湿环境中气态水吸附软化规律研究基础上，采用自主研发的深井软岩五联高温流变实验系统，对不同吸水阶段（含水率）软岩进行温压耦合流变实验，结合流变过程中软岩微观组构变化特征，从细微观角度探讨软岩的宏观蠕变特性，揭示深井软岩温压耦合吸水软化流变特性的非线性变化规律。建立考虑吸水软化损伤的温压耦合软岩流变本构模型，构建不同状态下软岩力学参数的快速反演分析方法，基于iTOUGH2多场耦合数值分析平台，研发与FLAC3D为平台的接口程序，定量分析深井软岩巷道大变形流变破坏过程与主控因素。提出基于恒阻大变形NPR锚杆/索支护的流变岩体相互作用模型，形成以变形能量控制为核心的深井软岩大变形流变NPR锚杆/索耦合控制方法，为深井高温高湿环境软岩巷道围岩稳定性控制提供理论与技术保障。

深井软岩巷道围岩通常表现出明显的流变特性，且在深部高温、高压、高湿复杂环境下，存在围岩强度软化流变机理不清、缺乏有效控制方法等问题，严重制约了深部煤炭安全高效开采。本项目针对深井软岩温压耦合吸水软化流变大变形特性进行研究，运用室内实验、数值模拟、理论分析等手段，结合现场实验监测，研究了复杂环境下深井软岩流变大变形机理，并提出相应的NPR耦合支护控制对策。通过实验获取了深井30℃-45℃温度下软岩气态、液态吸水规律，结合力学实验分析了水岩耦合大变形破坏主控因素、强度软化机理及微观破裂转化机制；采用自主研发的深井软岩五联流变实验系统，探究了水岩耦合条件下三阶段流变大变形破坏规律，建立了iTOUGH2与Flac3D数值耦合迭代计算方法，实现了对水岩耦合参数的优化；探究了水岩耦合作用及不同地应力水平在流变过程中对弹性变形及粘弹性变形的损伤演化规律，建立了基于水岩耦合损伤及应力损伤的稳态与加速流变过程力学模型，根据现场围岩状态在一定程度上能够有效的预测稳态及加速流变时间，减少短时间内加速大变形危害；通过拉伸实验研究了自主研发的新型NPR锚杆/索的基本力学特性，探究了以高预应力恒阻锚固为基础的开挖补偿原理，分析了三轴应力对阻止围岩稳态及加速流变的作用机制，在降低深井现场含水率基础上研究通过配合高预应力支护对控制巷道围岩流变大变形破坏、提高围岩稳定性的作用机理，提出了水岩耦合作用下NPR锚杆/索的控制对策。结合典型深部软岩巷道工程，研究了新型NPR锚杆/索巷道围岩流变大变形控制对策及其应用效果，为深井高温高湿环境软岩巷道围岩稳定性控制提供理论指导与技术保障。