深埋软岩隧道流变特征研究

发布时间：2018-01-18 06:35

本文关键词：深埋软岩隧道流变特征研究　出处：《西南交通大学》2014年博士论文　论文类型：学位论文

【摘要】：岩体变形是一个与时间相关的过程,尤其是软岩,其变形通常具有一定的时效性。弹塑性理论无法描述和预测这一过程,而流变力学理论较好的克服了这个缺点。合理描述岩体与时间相关的力学特征和行为对于实际工程有着重要的意义。本论文以锦屏二级水电站引水隧洞西端绿泥石片岩段为工程依托,基于相关试验和现场实测变形,采用理论分析和数值计算等方法,从岩石流变本构模型出发,研究了适合于描述软岩隧道流变特性的本构模型,并将该模型应用于数值模拟中,同时还研究了流变参数反演的方法。主要研究内容及成果包括以下几个方面：(1)对工程区绿泥石片岩进行了室内试验。采用扫描电镜-能谱分析对绿泥石片岩的微结构特征及元素组成进行了分析；采用岩石力学刚性试验机对绿泥石片岩干燥及饱和状态下的力学特征进行了研究,以期获得对绿泥石片岩在高地应力状态下变形和破坏特征的认识；(2)根据Riemann-Liouville分数阶微积分理论,提出了统一采用基于分数阶微积分形式表达的四元件非线性粘弹塑性流变模型,给出了该模型的本构方程及蠕变方程,并将该模型与绿片岩蠕变试验及岩盐蠕变试验数据分别进行了拟合,结果表明该模型可以有效反映岩石三个阶段的蠕变特性,并且起到了减少模型元件个数及参数的作用；(3)提出了蠕变三个阶段过程中非定常参数分别随时间和随应变衰减的方程,并根据衰减方程建立了改进三参量H-K流变模型,并结合相关试验数据对模型进行了辨识,结果显示两种参数衰减的形式均能较好的反映岩石蠕变的三个阶段；(4)推导了基于分数阶Maxwell模型的隧道粘弹性位移解析方程,同时考虑了掌子面及支护作用的影响,通过与Burgers模型的解析解对比,显示两种模型在某个时间段可以达到相一致的结果；(5)基于岩石蠕变三阶段的特点,提出了蠕变参数随等效应变而衰减的改进三参量H-K(广义Kelvin)三维本构模型,并用来反映软弱围岩在不同应力水平下的弹性变形及蠕变变形,同时给出了该模型应用于有限差分程序FLAC3D中的方法,即采用FLAC3D内嵌的FISH语言,在计算过程中动态评估和修正蠕变参数；(6)基于改进三参量H-K本构模型,采用有限差分程序FLAC3D探讨了软岩隧道在不同埋深及侧压力系数时的蠕变变形特征、掌子面对隧道流变的影响、施工停止时间对隧道流变的影响以及台阶法开挖对隧道流变的影响；(7)结合绿泥石片岩蠕变试验及现场实测数据,探讨了采用粒子群算法对流变参数反演的方法,同时将有限差分程序FLAC3D、均匀设计法、BP神经网络及粒子群算法相结合,建立了工程岩体流变参数的综合反演方法；(8)结合实际工程施工,并基于改进三参量H-K本构模型,采用FLAC3D程序分析了特殊支护(预应力锚索及锚筋桩)对深埋软岩隧洞流变的影响,结果显示,针对局部变形较大的地方施加预应力锚索可以起到一定的抑制作用,同时施加锚筋桩后,开挖下台阶更为安全有利。
[Abstract]:Rock deformation is a time-dependent process, especially the soft rock, the deformation usually has a certain timeliness. The elastic-plastic theory to describe and predict the process, and the rheological theory can overcome this disadvantage. The reasonable description of rock mechanics and time related characteristics and behaviors have significant for the practical engineering. This paper takes Jinping two hydropower station west of green clay schist segment based on the project, deformation related experiments and field based on the theoretical analysis and numerical calculation, the rheological constitutive model of rock based on a suitable constitutive model to describe the rheological properties of soft rock tunnel and the model is applied to the numerical simulation, the method of inversion of rheological parameters is also studied. The main research contents and results are as follows: (1) in the project area and green clay schist in the room In the experiment. By scanning electron microscope and energy spectrum analysis of chlorite schist the microstructure and element composition were analyzed by using the rock mechanics; rigid testing machine for mechanical characteristics of chlorite schist dry and saturated conditions were studied, in order to obtain the understanding of chlorite schist deformation and failure characteristics in high geostress condition; (2) according to the Riemann-Liouville fractional calculus theory, put forward the unified expression based on fractional calculus form four component nonlinear visco elastoplastic rheological model, the constitutive equation and creep equation of the model is given, and the test data and the model of creep of rock salt and GREENSCHISTS creep are fitted respectively. The results show that the the model can effectively reflect the creep characteristics of the rock in three stages, and to reduce the number of components and parameters of the model; (3) put forward three creep A stage in the process of unsteady parameters with time and strain attenuation equation, and the improved three parameter H-K rheological model is established according to the attenuation equation, combined with the identification model of test data, the result shows that the three stage of the two kinds of rock creep attenuation parameters are better; (4 tunnel) visco elastic displacement analytic equation of fractional order based on Maxwell model is deduced, considering the working face and the supporting effect of contrast solution by analytical and Burgers model, showed that two kinds of model can achieve consistent results in a certain period of time; (5) the characteristics of rock creep based on the three stage. The creep parameters with strain and attenuation of the improved three parameter H-K (generalized Kelvin) three-dimensional constitutive model, and used to reflect the weak surrounding rock under different stress deformation elastic deformation and creep stress level, and gives the The model is applied to finite difference method in the FLAC3D program, which uses FLAC3D FISH language embedded in the calculation process, the dynamic evaluation and correction of creep parameters; (6) improved three parameter H-K constitutive model based on the characteristics of creep deformation by finite difference program FLAC3D of soft rock tunnel in different depth and when the lateral pressure coefficient. The effect of the working face of tunnel construction excavation rheology, stop time effect on the tunnel rheological effect on tunnel rheological and step method; (7) based on the measured data of chlorite schist creep test and field was studied by using particle swarm optimization method of rheological parameter inversion, and the finite difference program FLAC3D, uniform design method, combining BP neural network and particle swarm algorithm, integrated inversion method to establish the rheological parameters of engineering rock mass; (8) combined with the actual construction, and based on the modified three parameter H-K constitutive The model, using FLAC3D analysis to special support (prestressed anchor cable and anchor pile) of deep soft rock tunnel, the rheological results show that the local deformation of large local applied prestressed anchor can play a certain inhibitory effect, while applying anchor pile after the excavation steps is safer and more favorable.

【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U451

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