裂隙岩体应变软化本构模型及其在软弱破碎巷道中的应用
发布时间：2019-06-10 04:42
【摘要】：随着煤矿开采不断向深部发展,地应力随之增大,工程地质条件更加恶劣,岩体软化现象愈发明显,内部的节理裂隙逐渐发育,力学性质发生变化,变形模量及各种力学参数随之降低,岩体变得软弱而破碎,加大了巷道围岩支护的难度。为有效维护软弱破碎巷道围岩的稳定性,有必要深入研究软弱破碎巷道围岩的变形破坏机理,为支护提供合理化建议。 根据软弱破碎巷道围岩的工程地质特征,首先从裂隙着手,通过对裂隙的野外观测,观察控制裂隙力学性质的主要参数。鉴于巷道围岩中裂隙的存在,认为裂隙岩体是蕴含损伤的连续体,并随裂隙的发育出现扩展,产生附加损伤。考虑到深部岩体峰后强度软化、裂隙大量发育等因素的影响,结合损伤力学和断裂力学,得到了裂隙岩体应变软化损伤本构方程。基于FLACm,在VC++的开发环境中,开发出裂隙岩体应变软化损伤本构模型。分别采用应变软化模型和裂隙岩体应变软化损伤模型对深埋圆形巷道进行数值模拟,将两种模型计算下的围岩变形、塑性区分布和安全系数进行对比分析,验证模型的合理性；接着对裂隙的倾角,裂隙的长度对巷道围岩稳定性的影响进行数值模拟研究。研究表明：随着裂隙倾角的增大,塑性区和位移量出现了先增大后减小的趋势,说明存在一个最不利倾角,在该倾角下,巷道围岩最不安全。伴随裂隙长度的增大,巷道围岩的塑性区和变形量都明显增大。 以淮北矿业集团芦岭矿为背景,将裂隙岩体应变软化损伤本构模型应用到受上覆工作面影响下的-590大巷围岩稳定性的分析中。对多种支护方案进行数值模拟,分析在各种支护方式下围岩巷道的位移、应力及塑性区的分布特点,结果表明锚喷+锚索+锚注的支护方式可以有效得控制巷道变形破坏,能较好得维护好巷道围岩的稳定性。 结合数值模拟的分析研究,将上述支护方案应用到实际的工程中。现场的观测数据表明,巷道围岩的变形破坏得到了有效的改善,观测的变形量和模拟结果大体一致,证明建立的裂隙岩体应变软化损伤本构模型能较好的模拟深部软弱破碎岩体的力学特性,可以为工程实践提供合理的指导。
[Abstract]:With the continuous development of coal mining to the deep, the ground stress increases, the engineering geological conditions become worse, the rock mass softens more obviously, the internal joint fissures develop gradually, and the mechanical properties change. With the decrease of deformation modulus and various mechanical parameters, the rock mass becomes weak and broken, which makes it more difficult to support the surrounding rock of roadway. In order to effectively maintain the stability of the surrounding rock of the weak broken roadway, it is necessary to deeply study the deformation and failure mechanism of the surrounding rock of the weak broken roadway, and to provide reasonable suggestions for support. According to the engineering geological characteristics of the surrounding rock of weak and broken roadway, the main parameters controlling the mechanical properties of cracks are observed through the field observation of cracks. In view of the existence of cracks in the surrounding rock of roadway, it is considered that the cracked rock mass is a continuum containing damage, and the additional damage occurs with the development of cracks. Considering the influence of strength after peak and large number of cracks in deep rock mass, combined with damage mechanics and fracture mechanics, the strain softened damage constitutive equation of fracture rock mass is obtained. Based on FLACm, in the development environment of VC, the strain softened damage constitutive model of fracture rock mass is developed. Strain softened model and fracture rock mass strain softened damage model are used to simulate the deep buried circular roadway respectively. the deformation, plastic zone distribution and safety factor of surrounding rock calculated by the two models are compared and analyzed to verify the rationality of the model. Then the influence of the dip angle of the crack and the length of the crack on the stability of the surrounding rock of the roadway is studied by numerical simulation. The results show that with the increase of fracture inclination angle, the plastic zone and displacement tend to increase at first and then decrease, indicating that there is one of the most unfavorable dip angles, and the surrounding rock of roadway is the least safe under this inclination angle. With the increase of fracture length, the plastic zone and deformation of roadway surrounding rock increase obviously. Based on Luling Mine of Huaibei Mining Group, the strain softened damage constitutive model of fissured rock mass is applied to the analysis of surrounding rock stability of-590 roadway under the influence of overlying working face. The numerical simulation of various supporting schemes is carried out, and the distribution characteristics of displacement, stress and plastic zone of surrounding rock roadway under various supporting modes are analyzed. The results show that the supporting mode of anchor shotcrete anchor cable anchor grouting can effectively control the deformation and failure of roadway. It can maintain the stability of roadway surrounding rock. Combined with the analysis and research of numerical simulation, the above support scheme is applied to the actual project. The field observation data show that the deformation and failure of roadway surrounding rock has been effectively improved, and the observed deformation is in good agreement with the simulation results. It is proved that the strain softened damage constitutive model of fracture rock mass can simulate the mechanical properties of deep weak broken rock mass and can provide reasonable guidance for engineering practice.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD353
本文编号：2496179
[Abstract]:With the continuous development of coal mining to the deep, the ground stress increases, the engineering geological conditions become worse, the rock mass softens more obviously, the internal joint fissures develop gradually, and the mechanical properties change. With the decrease of deformation modulus and various mechanical parameters, the rock mass becomes weak and broken, which makes it more difficult to support the surrounding rock of roadway. In order to effectively maintain the stability of the surrounding rock of the weak broken roadway, it is necessary to deeply study the deformation and failure mechanism of the surrounding rock of the weak broken roadway, and to provide reasonable suggestions for support. According to the engineering geological characteristics of the surrounding rock of weak and broken roadway, the main parameters controlling the mechanical properties of cracks are observed through the field observation of cracks. In view of the existence of cracks in the surrounding rock of roadway, it is considered that the cracked rock mass is a continuum containing damage, and the additional damage occurs with the development of cracks. Considering the influence of strength after peak and large number of cracks in deep rock mass, combined with damage mechanics and fracture mechanics, the strain softened damage constitutive equation of fracture rock mass is obtained. Based on FLACm, in the development environment of VC, the strain softened damage constitutive model of fracture rock mass is developed. Strain softened model and fracture rock mass strain softened damage model are used to simulate the deep buried circular roadway respectively. the deformation, plastic zone distribution and safety factor of surrounding rock calculated by the two models are compared and analyzed to verify the rationality of the model. Then the influence of the dip angle of the crack and the length of the crack on the stability of the surrounding rock of the roadway is studied by numerical simulation. The results show that with the increase of fracture inclination angle, the plastic zone and displacement tend to increase at first and then decrease, indicating that there is one of the most unfavorable dip angles, and the surrounding rock of roadway is the least safe under this inclination angle. With the increase of fracture length, the plastic zone and deformation of roadway surrounding rock increase obviously. Based on Luling Mine of Huaibei Mining Group, the strain softened damage constitutive model of fissured rock mass is applied to the analysis of surrounding rock stability of-590 roadway under the influence of overlying working face. The numerical simulation of various supporting schemes is carried out, and the distribution characteristics of displacement, stress and plastic zone of surrounding rock roadway under various supporting modes are analyzed. The results show that the supporting mode of anchor shotcrete anchor cable anchor grouting can effectively control the deformation and failure of roadway. It can maintain the stability of roadway surrounding rock. Combined with the analysis and research of numerical simulation, the above support scheme is applied to the actual project. The field observation data show that the deformation and failure of roadway surrounding rock has been effectively improved, and the observed deformation is in good agreement with the simulation results. It is proved that the strain softened damage constitutive model of fracture rock mass can simulate the mechanical properties of deep weak broken rock mass and can provide reasonable guidance for engineering practice.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD353
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