露天矿高含水煤岩边坡蠕变损伤机理研究

In Eastern Mongolia,the amount of coal resources suitable for open pit exploitation accounts for 28.28% of the total amount.In this area,slope of open-pit mine has a character of low strength, high water content, poor permeability and weak layer complex.The slope is prone to deformation and instability under the action of coupled seepage and creep damage factors.The project adopts comprehensive research methods combined by field investigation,theoretical analysis, experimental study, numerical simulation and field application. The characteristics of rock structure and deformation aging characteristics of high water filled coal rock slope are studied, and the relationship between the safety factor and the weakening of shear strength is analyzed,and the instability and failure law of the slope is obtained. By using the three axis seepage-creep experiment ,the relation curve and equation between confining pressure of coal rock and pore water pressure rupture strength, damage degree of coal rock and confining pressure could be obtained. Under the condition of static and dynamic pressure, the relationship between the safety factor of the high water cut coal rock slope, the water filling pressure and the crack opening is obtained by using the self-made plane model experiment system. The coupling model between creep damage criterion and seepage-creep damage is established,which could be solved by the finite element method . The coupling program of seepage creep damage is developed to reveal the evolution mechanism of high water filled coal rock slope disaster. Research achievements are applied to typical mining district.The research would provide a theoretical basis for the evolution, forecast, prediction, optimization of mining scheme and stability control of high water filled coal rock slope.

蒙东地区适合露天开发的煤炭资源量占露采资源总量的28.28%，该区露天矿边坡强度低、含水量大、渗透性差、弱层赋存复杂，边坡在渗流-蠕变损伤耦合因素作用下易发生变形失稳。项目采取现场考察、理论分析、实验研究、数值模拟和现场应用相结合的综合性研究方法，研究高含水煤岩边坡岩层结构特征和变形时效特性，分析其安全系数与抗剪强度弱化的关系，获得边坡失稳破坏规律；利用煤岩三轴渗流-蠕变实验，得出煤岩围压-孔隙水压破裂强度及煤岩损伤度与围压关系曲线和方程；应用自制平面模型实验系统，在变静水压和动水压情况下，得出高含水煤岩边坡安全系数、充水压力及裂缝张开度的关系式；建立含水煤岩蠕变损伤断裂判据与渗流-蠕变损伤耦合模型，对其进行有限元求解，开发煤岩体渗流-蠕变损伤耦合计算程序，揭示高含水煤岩体蠕变损伤机理，选取典型矿区进行现场应用。研究为高含水煤岩边坡灾害演化、预测预报、开采方案优化、稳定性控制提供理论基础。

高含水煤岩边坡在重力、渗水等因素耦合作用下的变形、破坏、工程控制以及监测监控问题贯穿富水软岩矿区露天矿建设、生产乃至闭坑全过程，是制约该类露天矿山安全、高效生产的控制因素。. 项目采取现场考察、理论分析、实验研究、数值模拟和现场应用相结合的综合性研究方法，对高含水软岩矿山进行了系统的调研，确定了高含水煤岩边坡岩层结构特征。统筹考虑复杂地质环境下矿山岩体的各种破坏工况，确定了其灾害演化的控制变量。开展煤岩边坡充水和渗水条件下蠕变损伤规律试验研究，总结各种工况条件下煤岩试件的物理力学参数在水作用下的弱化规律，探讨了高含水煤岩边坡变形时效特性和水作用下边坡系统变形演化规律。通过开展渗流—应力场共同作用下煤岩体的损伤机理研究，建立了煤岩体渗流-损伤耦合本构模型和高含水煤岩体非线性蠕变损伤模型及损伤判据。建立了高含水煤岩边坡安全评估体系，在理论研究的基础上，结合工程实践，形成了“理论+调查+勘察+试验+建模+评估+参数优化+再评估”的全周期评估体系，寻找对灾害演化过程起控制作用的控制变量，研究其对演化过程及演化趋势的支配作用，从而为灾害控制提供理论依据。选取典型高含水煤岩矿区，将研究成果转化应用，利用地质勘察、抽水试验、模型创建、数值模拟及稳定分析等方法，分析充水煤岩的变形、破坏、破裂及滑塌机理，评估边坡稳定性，总结加固、预测、预报和评估方法。. 项目注重成果与工程实践的有机结合，将成果动态应用到现场工程中进行检验并不断修正，研究期间先后在华能伊敏河露天煤矿、云天化东明露天煤矿和神华宝日希勒露天煤矿开展相关课题6项，依托实际工程开展了大型边坡勘察、抽水试验、边坡变形演化过程监测、开采优化设计和灾害治理工程，现场原位试验弥补了室内试验的局限，应用反馈提高了成果的适用性。项目成果有利于预测、预报、评价、治理等重大问题的进一步研究，对高含水煤岩体蠕变损伤机理研究具有科学价值和重要的工程意义。