弱胶结围岩巷道卸荷扩容流变破坏机理与控制基础研究

As the exploitation of coal resources in the west of China, the roadway support problem induced by the weak-cemented surrounding rock is more and more obvious. The research on the failure mechanism of weak-cemented surrounding rock and its control under unloading-creep condition is of great significance. Based on the methods of theoretical analysis, laboratory test, numerical simulation and field monitoring, this project will mainly be carried out on three aspects. First, the influence of physical components and microscopic structures on the micro crack initiation, crack evolution and failure of weak-cemented rock will researched by X-ray diffraction, SEM electron microscope scanning and unloading-creep tests. The unloading-creep constitutive model of weak-cemented rock will be established by considering the physical components and microscopic strucutres.Second, the fracture characteristics of weak-cemented rock will be researched under the unloading condition based on the methods of creep test, filed detection, similar materials simulation and digital speckle test. The accumulation law of creep dilatancy and the failure mechanism for weak-cemented rock will be revealed. The failure criterion of the surrounding rock, which is induced by the behavior of creep dilatancy, will be proposed.Third, based on accurate control of the creep-dilatancy deformation of the week-cemented surrounding rock, the anchorage-preloaded supporting mechanics model for the dilatancy zone of weak-cemented surrounding rock will be constructed. A design method of finite deformation control for weak-cemented surrounding rock will be proposed. Research results of this project will provide a scientific basis for the safety of the support of the weak-cemented roadway in the west of China.

随着我国西部煤炭资源的开采，弱胶结围岩带来的巷道支护难题日益凸显，深入探究弱胶结围岩卸荷扩容流变破坏机理及控制意义重大。本项目拟采用理论分析、室内试验、数值模拟和现场探测相结合的研究方法，开展以下方面的创新性工作：① 采用X射线衍射、SEM电镜扫描和流变试验手段，探究物性组分、细观结构对弱胶结岩石卸荷流变微裂纹萌生、扩展演化、破坏失稳影响规律，建立考虑物性组分、细观结构等影响因素的弱胶结岩石卸荷扩容流变本构关系；② 通过流变试验、现场探测、相似材料模拟与数字散斑同步试验方法，研究开挖卸荷弱胶结围岩破裂展布特征，揭示弱胶结岩石扩容流变累积-破坏-失稳规律，提出扩容流变引起围岩破坏失稳判据；③ 探索以调控流变变形量为核心的精准控制思路，构建弱胶结围岩扩容区锚固预紧支护结构力学模型，提出弱胶结围岩有限变形控制设计方法。本项目研究成果将为我国西部弱胶结巷道安全支护提供科学依据。

随着我国西部煤炭资源的开采深度增加，中深部弱胶结软岩巷道支护难题日益突出，尤其是超长回采巷道情况下，深入探究中深部弱胶结软岩巷道流变破坏及锚固支护意义重大。本项目按照计划任务书的要求，通过室内试验、理论探究、数值模拟、相似材料模拟与现场实测试验相结合的综合研究方法，围绕弱胶结围岩巷道卸荷扩容流变破坏机理与控制开展攻关研究，取得如下创新性成果：（1）提出弱胶结软岩定量评价分类指标，获取弱胶结岩石的单轴抗压强度和内聚力随粘土矿物含量增加呈线性降低趋势，采用这两个指标将弱胶结软岩划分为一般、弱和极弱三类；（2）基于流变试验结果，以经典黏弹塑性模型为基础，从内聚力、内摩擦角和弹性模量三个参量出发，构建弱胶结软岩卸荷流变本构关系；（3）现场探测发现，弱胶结软岩围岩分为相对完整区、浅部破裂区和深部完整区，探测初期浅部破裂区范围大小约为2.7m，随着时间增大，逐渐扩展至顶板6.0m深度；（4）采用以顶板破裂分布范围、锚杆（索）极限拉拔力、钻孔钻进速度为核心的潜在坍塌危险性顶板岩层范围确定方法；（5）研究发现弱胶结软岩顶板锚固支护预紧力偏低是顶板失稳的主控因素，提出弱胶结软岩高预紧力下锚杆-围岩变形协同支护原理，在最大程度的发挥锚杆-锚索支护效能的同时锚杆、锚索变形与顶板变形下沉协同、相适应。本项目研究成果发表论文10篇，其中SCI /EI论文7篇；参加国内外学术会议6人次；获得省部级一等奖1项、厅局级二等奖1项；授权国家发明专利3项、国际发明专利1项；培养硕士4名(已毕业3名)。本项目研究成果为我国西部地区巷道安全支护与掘进支护智能化，提供理论支持与科学依据，应用价值高。