【作者】 牛双建；

【导师】 靖洪文；

【作者基本信息】 中国矿业大学 ， 岩土工程， 2011， 博士

【摘要】 以山东郓城煤矿千米深井深部典型破坏巷道为工程背景,综合采用真三轴物理模拟、室内MTS岩样试验、理论分析和数值模拟系统深入的对深部巷道围岩强度衰减规律这一关键科学问题进行了研究。主要研究内容及取得的成果如下:(1)采用WYQ1000-I型地下工程大尺度真三轴模拟试验系统,按照先加载后开挖的方式,物理模拟研究了深部巷道围岩开挖卸荷效应的全过程;揭示了巷道围岩在无支护条件下的破坏模式;获得了不同深度处围岩真实的加卸载路径及开挖前后应力状态结果,重点分析探讨了松动圈内围岩主应力差演化规律及机理;建立了松动圈内围岩主应力差峰值后跌落幅度与其损伤程度的对应关系。(2)基于物理模拟获得的松动圈内围岩的应力路径,采用MTS试验机进行了岩样的加卸载试验,获得了与松动圈内各位置围岩损伤程度相一致的初始损伤岩样;采用多级围压多次峰值屈服的试验方法对其在不同围压下的强度及变形参数进行了测定,研究得出了损伤岩样强度衰减及其围压对其强度衰减幅度的影响规律;分别选用卸载点应力减低比Dσ和体积膨胀比DV为损伤因子,建立了损伤岩样峰值强度及强度参数与Dσ、DV两者之间的函数关系;结合损伤岩样与松动圈内围岩对应关系,初步建立了深部巷道围岩峰后强度参数衰减的模型。(3)通过对试验建立的深部巷道围岩峰后强度参数衰减模型中塑性参数的替换推导,将该模型植入了FLAC3D数值模拟分析软件;结合实际工程,更深入地研究了深部巷道围岩破裂过程中围岩应力场(重点为围岩主应力差)及位移场的演化规律,并与物理模拟和工程现场测试结果进行了对比分析,验证了所建立模型的合理性。(4)鉴于巷道围岩强度衰减伴随裂隙不断扩展及贯通的事实,现场选取具有不同破裂面分布的破裂岩样,对其进行了零围压条件下的再破坏试验,研究了围岩破坏过程中强度衰减及能耗特征参数与破碎程度的关系;结合试验数据建立了破裂岩样峰值强度、峰值点各能耗特征参数指标与破裂面分形维数D的函数关系;同时对破裂岩样单轴压缩再破坏过程中的声发射特征进行了研究。该论文有图95幅,表34个,参考文献136篇。更多还原

【Abstract】 In allusion to the engineering background of a roadway embedded about one kilometer underground in Shandong Yuncheng Mine, study is taken to get the strength attenuation law of surrounding rock by ways of true triaxial physical simulation, rock sample test with MTS, theoretical analysis and numerical simulation. The main research contents and conclusions are as follows:(1) With WYQ1000-I large scale three-dimension test system for underground engineering simulation, the full unloading process of surrounding rock of a deep roadway is physically simulated. The results show the failure patterns of surrounding rock without support, and the actual loading-unloading paths and stress states of the surrounding rock in different distances from roadway periphery. Based on the test data, this dissertation analyses the evolution law of deviatoric stress in broken rock zone of the roadway, establishes the corresponding relation between damage degree of surrounding rock inside the broken rock zone and its decreased degree of deviatoric stress at post-peak.(2) According to the stress paths of the surrounding rock obtained by physical simulation, rock samples are tested on the MTS test machine. First, the rock specimens which have the same damage extent with the surrounding rock are obtained. Then the strength and deformation parameters of these specimens are measured under different confining pressures. By analyzing the test results, the author gains the law of strength attenuation of injured rock samples and the influence of confining pressure on strength attenuation extent, establishes the post-peak strength degradation model of rock around the deep roadway by setting the relation between strength parameters and two damage factors (i.e., stress reducing ratio Dσand volume expansion ratio DV).(3) The post-peak strength degradation model for surrounding rock of a deep roadway is embedded in FLAC3D numerical simulation software. Using the software, further study is done on the evolution law of stress (especially the emphasis is placed on the deviatoric stress) and strain fields in the fracturing process of rock surrounding the deep roadway. The results of numerical simulation are compared with the indoor physical simulation as well as the in-site measurement, which verifies the rationality of the model.(4) Based on the fact that the surrounding rock strength attenuation is usually coupled with fracture expanding and penetrating, fractured rock samples with different distributions of discontinuities are tested under zero confining pressure to study the relation between the strength degradation, energy feature parameters and the damage extent of surrounding rock. The functional relation is developed between peak strength, energy feature parameters at peak point and fractal dimension D. Furthermore, the acoustic emission features in the refracturing process of damaged rock samples are investigated under uniaxial compression.This article includes 95 images, 34 tables and 136 references.更多还原