极弱胶结岩体结构与力学特性及本构模型研究

发布时间：2018-04-09 21:21

本文选题：极弱胶结岩体　切入点：结构与力学特性　出处：《中国矿业大学》2014年博士论文

【摘要】：极弱胶结岩体是广泛分布在我国西部矿区侏罗系、白垩系地层中的一类特殊软岩，特殊的成岩环境和沉积过程，形成了其独特的物理与力学性质。由于在极弱胶结岩体的研究中存在一系列的难题，目前对极弱胶结岩体的基本物理力学性质试验及本构模型的相关研究涉及甚少。随着西部矿井的大规模建设，极弱胶结地层巷道围岩控制问题逐渐突出，亟需开展极弱胶结岩体的物理力学性质试验与本构模型方面的研究，对我国西部矿区的建设与安全生产具有重要现实意义和工程应用价值。本文以极弱胶结岩体为研究对象，综合运用岩体试验、理论分析、数值模拟等技术手段，研究了不同应力状态及含水率条件下极弱胶结岩体的物理与力学特性，揭示了围岩再生结构的形成过程及围岩位移、塑性区与应力分布的演化规律，构建了极弱胶结岩体扩容大变形本构模型，分析了极弱胶结岩体扩容大变形破坏机理，提出了极弱胶结地层巷道围岩控制技术。论文研究主要成果与进展：（1）自主研制了极弱胶结岩体再生结构形成试验装置，确定了再生结构岩样分级加载与固结稳定方法，形成了不同含水率极弱胶结岩体再生结构岩样，揭示了再生结构岩样的形成过程及结构与力学特性。（2）基于裂纹体积应变模型，分析了极弱胶结岩体扩容大变形破坏机理，反映了不同应力状态与含水率条件下极弱胶结岩体应力-应变曲线特性，揭示了岩体强度与扩容参数随等效塑性应变及含水率变化的演化规律。（3）建立了峰前损伤扩容与峰后破裂扩容屈服准则，修正了Mohr-Coulomb准则剪切与拉伸破坏区域的划分条件，构建了极弱胶结岩体扩容大变形本构模型，揭示了极弱胶结岩体峰后应变软化与扩容变形特性。（4）确定了极弱胶结岩体本构模型的增量迭代格式，实现了极弱胶结岩体扩容大变形本构模型的二次开发，揭示了不同埋深、侧压力系数及剪胀角等条件下巷道围岩位移、塑性区与应力分布的演化规律。（5）提出了应用切圆拱形断面与双层锚固平衡拱结构，基于煤层厚度与巷道埋深影响效应，提出了极弱胶结地层回采巷道分类支护技术方案，揭示了巷道围岩变形与支护结构受力演化规律，，并成功应用于工程实践。
[Abstract]:The very weak cemented rock mass is a kind of special soft rock which is widely distributed in Jurassic and Cretaceous strata in western China. The special diagenetic environment and sedimentary process form its unique physical and mechanical properties.Due to a series of difficult problems in the study of very weak cemented rock mass, there is little research on the basic physical and mechanical properties of the very weak cemented rock mass and the related research on the constitutive model of the very weak cemented rock mass.With the large-scale construction of the west coal mine, the problem of controlling the surrounding rock of the roadway in the very weak cemented strata is becoming more and more serious. It is urgent to study the physical and mechanical properties of the very weak cemented rock mass and the constitutive model.It has important practical significance and engineering application value for the construction and safe production of mining area in western China.Taking the very weak cemented rock mass as the research object, the physical and mechanical properties of the very weak cemented rock mass under the condition of different stress states and moisture content are studied by means of rock mass test, theoretical analysis and numerical simulation.The forming process of surrounding rock regeneration structure and the evolution law of surrounding rock displacement, plastic zone and stress distribution are revealed. The constitutive model of dilatancy and large deformation of very weak cemented rock mass is constructed, and the failure mechanism of very weak cemented rock mass is analyzed.The control technology of surrounding rock of roadway in very weak cemented stratum is put forward.The main achievements and progress of this paper are as follows:In this paper, an experimental device for the formation of regenerative structure of very weak cemented rock mass has been developed. The method of graded loading and consolidation stability of recycled rock samples has been determined, and the rock samples with very weak cemented rock mass with different moisture content have been formed.The formation process, structure and mechanical properties of regenerated rock samples are revealed.(2) based on the crack volume strain model, the mechanism of dilatancy and large deformation of very weak cemented rock mass is analyzed, which reflects the stress-strain curve characteristics of very weak cemented rock mass under different stress states and water content.The evolution law of rock mass strength and expansion parameters with the change of equivalent plastic strain and water content is revealed.(3) the pre-peak damage expansion criterion and post-peak fracture expansion yield criterion are established, the Mohr-Coulomb criterion is modified to divide the shear and tensile failure regions, and the constitutive model of the dilatancy and large deformation of the very weak cemented rock mass is constructed.The characteristics of strain softening and expansion deformation after peak of very weak cemented rock mass are revealed.(4) the incremental iterative scheme of the constitutive model of very weak cemented rock mass is determined, the secondary development of the constitutive model of the very weak cemented rock mass with large deformation is realized, and the displacement of surrounding rock of roadway is revealed under the conditions of different burying depth, lateral pressure coefficient and shear-expansion angle, etc.The evolution of plastic zone and stress distribution.Based on the effect of coal seam thickness and roadway depth, this paper puts forward the technical scheme of classified support for mining roadway in very weak cemented strata, which is based on the application of tangential arch section and double-layer anchor balanced arch structure, based on the effect of coal seam thickness and roadway depth.The evolution law of surrounding rock deformation and supporting structure is revealed and successfully applied in engineering practice.
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU452

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