基于弹性应变能盐岩屈服准则及其工程应用研究

发布时间：2018-03-07 13:12

本文选题：盐岩　切入点：弹性应变能　出处：《重庆大学》2014年博士论文　论文类型：学位论文

【摘要】：盐岩不仅是一种重要的矿产资源，而且作为能源储存、有毒有害废弃物以及CO2地质处置的理想介质受到了各国的广泛重视，针对盐岩矿床开采与腔体的后续利用等问题，开展盐岩溶腔的稳定性研究具有重要的理论和工程应用价值。基于此，结合国家重点基础研究发展计划（973）（2009CB724606），在已有研究成果的基础上，从盐岩溶腔稳定性评价角度出发，以盐岩屈服破坏条件研究为主线，，采用试验研究、理论分析与数值仿真等综合手段，基于能量转化的基本原理，对盐岩屈服准则及其工程应用等进行了较为系统深入的研究。本文主要研究工作和成果如下： ①通过单轴压缩、三轴压缩、巴西劈裂等试验，研究了岩盐、无水芒硝、泥岩的强度与变形特征，并获得了抗压强度、抗拉强度、粘聚力、摩擦角、弹性模量、泊松比等力学参数；通过分级加载蠕变试验获得了围压和偏应力对稳态蠕变率的影响，建立了线性稳态蠕变率本构关系，并探讨了线性和经典的Norton-Power蠕变模型参数的变异对等速蠕变率的影响。 ②以弹性应变能为基础，通过定义能量分散系数建立了基于弹性应变能整体破坏推广准则，结果表明该准则所得理论值与三轴压缩的试验值较为吻合；分析表明，单轴抗压强度对该准则的理论值影响比较明显，而泊松比对该准则的影响相对较小。 ③为使基于弹性应变能的屈服与破坏准则较好的适用于盐岩，建立了基于弹性应变能盐岩的广义屈服与破坏准则，泊松比等于0.5时该准则将蜕化为D-P准则。分析表明粘聚力、泊松比对该准则的影响基本是线性的，而摩擦角对该准则的影响是非线性的；分别采用M-C准则与广义屈服与破坏准则对岩石的强度进行了计算，结果表明盐岩广义屈服与破坏准则的计算结果与试验值较为接近。 ④基于理想弹塑性模型，以盐岩广义屈服与破坏准则为剪切屈服函数，并考虑拉伸破坏，建立了可应用于盐岩的本构模型。通过C++程序，对该本构模型进行了二次开发，并嵌入FLAC3D软件用于数值计算。通过试验模拟分析验证了二次开发本构模型程序的正确性和合理性。 ⑤利用盐岩理想弹塑性本构模型二次开发的计算程序，对盐岩溶腔的静力稳定性与长期稳定性进行了数值分析。重点研究了溶腔塑性区、溶腔腔体位移、溶腔体积收敛及安全矿柱等随储气内压与蠕变时间的变化规律，确定了溶腔的最小内压、中淡化段厚度以及矿柱宽度。 ⑥盐岩、泥岩力学参数的变异对盐岩溶腔稳定性影响的研究表明：盐岩粘聚力、摩擦角对双溶腔塑性区扩展影响不明显；而泥岩摩擦角对双溶腔塑性区扩展影响较为明显。
[Abstract]:Salt rock is not only an important mineral resource, but also a kind of energy storage, toxic and harmful waste and ideal medium for CO2 geological disposal. The research on the stability of salt karst cavities has important theoretical and engineering application value. Based on this, combined with the national key basic research and development plan, 2009CB724606, based on the existing research results, from the point of view of the evaluation of the stability of salt karst cavities, Based on the basic principle of energy conversion, this paper takes the study of yield failure condition of salt rock as the main line, adopts comprehensive means such as experimental study, theoretical analysis and numerical simulation, etc. The yield criterion of salt rock and its engineering application are studied systematically and deeply. The main work and results of this paper are as follows:. 1 through uniaxial compression, triaxial compression and Brazilian splitting tests, the strength and deformation characteristics of rock salt, anhydrous mirabilite and mudstone are studied, and the compressive strength, tensile strength, cohesion, friction angle and elastic modulus are obtained. The influence of confining pressure and deflection stress on steady state creep rate is obtained by step loading creep test, and the constitutive relation of linear steady state creep rate is established. The influence of the variation of the parameters of the linear and classical Norton-Power creep model on the constant velocity creep rate is also discussed. 2 on the basis of elastic strain energy, by defining the energy dispersion coefficient, the generalized criterion of global failure based on elastic strain energy is established. The results show that the theoretical value obtained by the criterion is in good agreement with the experimental value of triaxial compression, and the analysis shows that, The uniaxial compressive strength has obvious influence on the theoretical value of the criterion, but Poisson's ratio has little effect on the criterion. In order to make the yield and failure criterion based on elastic strain energy more suitable for salt rock, a generalized yield and failure criterion based on elastic strain energy is established. When Poisson's ratio is equal to 0.5, the criterion will degenerate into D-P criterion. The influence of Poisson's ratio on the criterion is linear, and the influence of friction angle on the criterion is nonlinear. The strength of rock is calculated by M-C criterion and generalized yield and failure criterion, respectively. The results show that the calculated results of the generalized yield and failure criteria of salt rock are close to the experimental values. Based on the ideal elastic-plastic model, taking the generalized yield and failure criterion of salt rock as the shear yield function, and considering the tensile failure, a constitutive model of salt rock is established. The constitutive model is redeveloped by C program. The FLAC3D software is embedded in the numerical calculation, and the correctness and rationality of the secondary development constitutive model program are verified by the experimental simulation and analysis. 5. The static stability and long-term stability of salt karst cavity are numerically analyzed by using the calculation program of the ideal elastoplastic constitutive model of salt rock. The plastic zone of the cavity and the displacement of the cavity are studied emphatically. The minimum internal pressure, the thickness of the middle desalination section and the width of the ore column are determined by the variation of the volume convergence of the dissolved cavity and the safety pillar with the gas storage internal pressure and creep time. 6 the influence of variation of mechanical parameters of salt rock and mudstone on the stability of salt karst cavity shows that the cohesive force and friction angle of salt rock have no obvious influence on the expansion of plastic zone of double solution cavity, while the angle of friction of mudstone has more obvious effect on the expansion of plastic zone of double solution cavity.
【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU45

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