动载扰动下深部巷道围岩破裂演化及非线性失稳灾变机理

With the coal mining depth increasing, the complex stress environment composed by high ground stress and dynamic loading made the fracture and instability evolution of roadway surrounding rocks become very complicated. The support and control problems of deep roadway surrounding rocks are becoming more prominent. The aim of this research is to reveal the fracture evolution law and nonlinear instability mechanism of deep roadway surrounding rocks induced by dynamic disturbance. Based on the methods of laboratory test, theoretical analysis, numerical simulation and field monitoring, this research will mainly focus on three aspects. First, developing a testing method of the stress and strain of coal in coal-rock combined body under superposing of high stress and dynamic loading, testing the dynamic mechanical properties and damage evolution law of coal under different loading conditions and surrounding rocks, and establishing a dynamic damage constitutive model of coal considering the influences of surrounding rocks. Second, researching the influences of loading condition and surrounding rock property on the fracture characteristics of deep roadway, and revealing the fracture spatiotemporal evolution law of deep roadway surrounding rocks disturbing by dynamic loading. Third, deducing the nonlinear evolution process from fracture to instability of deep roadway surrounding rocks under dynamic loading, establishing a zonal structural mechanics model of deep roadway surrounding rocks, revealing the nonlinear instability mechanism of deep roadway surrounding rocks, and deriving an energy criterion. Research results will provide theoretical basis for the stability and control of underground engineering surrounding rocks under deep complex stress environment.

随着煤矿开采深度的增加，深部高应力与动载叠加的复杂应力环境使得巷道围岩破裂及失稳演化变的非常复杂，围岩支护与控制问题日益凸显。本项目以揭示动载扰动下深部巷道围岩破裂演化规律及非线性失稳灾变机理为研究目标，拟采用室内试验、理论分析、数值模拟和现场监测相结合的方法，研究如下内容：(1)探索高应力与动载叠加作用下煤岩组合体中煤的应力应变测试方法，得出不同载荷条件及围岩环境下煤的动力学特性及动态损伤演化规律，建立高应力与动载叠加下考虑围岩环境影响煤体的损伤本构模型；(2)研究载荷条件、围岩性质对深部巷道围岩破裂范围及展布的影响，揭示动载扰动下深部巷道围岩破裂时空演化规律；(3)推演动载扰动下深部巷道围岩破裂至失稳致灾的非线性演化过程，构建围岩分区结构力学模型，揭示其非线性失稳灾变机理，并提出围岩失稳的能量判据。研究结果可为深部复杂应力环境下地下工程围岩稳定与控制提供理论依据。

针对深部高应力与动载叠加下巷道围岩变形破裂严重、控制难度大的问题，本项目采用理论分析、数值模拟、相似材料试验和现场监测的综合研究方法，首先，基于应变直测技术和PVDF压电特性，提出了煤岩组合体中煤应力应变关系的测试方法，揭示了不同岩石性质、煤岩高度比等条件下受动静载荷作用时组合体中煤的变形破坏规律。其次，建立了能表征煤岩压密过程的煤岩单体损伤本构模型，构建了静载、动载及动静组合加载下组合体中煤的损伤本构模型，能较好地描述动静载荷下组合体中煤的变形受力关系。然后，利用多种监测手段，获得了新河煤矿典型深部巷道围岩断裂、顶板垮落及断层滑移等产生的动载特征，获得不同动载扰动作用后围岩新增破裂范围及展布特征，结合相似材料模拟试验和数值模拟，获得了动载特征、初始静载和覆岩性质等因素对巷道围岩破裂的影响，动载荷强度增大、初始静载荷增大和顶板岩层抗压强度增大，都将使巷道两帮煤体塑性区范围增大，并使巷道两帮煤体内积聚能量增大。最后，构建了动载荷作用下巷道围岩结构力学模型，将巷道两帮煤层划分为阻力区、驱动区和无明显影响区，揭示了动载荷下巷道围岩破坏失稳孕育演化过程，并推导了围岩失稳的能量判据。项目研究过程中，在国内外重要学术期刊发表论文20篇，其中SCI收录16篇，EI收录3篇；申请发明专利20项，其中美国专利3项、日本专利2项；参加国内外学术会议6次；培养/协助培养研究生4名；制定国家标准1项；获得全国协会一等奖1项、二等奖2项。