饱和黄土动力本构模型及地铁隧道周围土层变形分析
发布时间：2018-08-24 19:12
【摘要】：地铁长期运行的重要影响之一是地层沉降、差异沉降及其所致的次生问题。未来几年,西部黄土地区将展开一定规模的城市轨道建设,以西安地铁为例,其大部分正线段均在地下水位以下,属于力学性能较差的饱和黄土。地铁荷载对地层累积变形的影响更不能小觑。目前,鲜见综合考虑饱和黄土结构性、各向异性、地铁循环荷载特性的动力本构模型,本文将综合考虑这三种因素的影响,建立一种新的土动力本构模型,并将其应用于地铁隧道周围地层的沉降特性分析,取得了如下研究成果： (1)将土的结构性因子划分为各向同性结构性因子Di和各向异性结构性因子Dr,假定各向异性结构性损伤对边界面的各向异性张量和临界状态线斜率均有影响,建立了考虑各向异性结构性影响的旋转硬化法则。同时,沿用了前人所建立的考虑各向同性结构性损伤影响的等向硬化法则。 (2)综合考虑循环加卸载影响及前两种硬化法则,建立了映射中心的运动硬化法则,假定在加载方向改变时,映射中心会移至应力反向点处,且随着边界面的前两种硬化过程而发生运动硬化。 基于Dafalias边界面模型及上述三种硬化法则,建立了综合考虑各向异性、结构性和循环动荷载作用的饱和黄土动力边界面本构模型。对模型参数进行了分类,并详细描述了各参数的物理意义及确定方法。 (3)将本文边界面模型编写成UMAT子程序,利用ABAQUS有限元软件模拟了饱和黄土试样的室内动、静三轴试验过程,利用数值模拟结果与室内试验结果的一致性验证了本文本构模型及UMAT子程序的合理性。 (4)基于此UMAT子程序及建立的间歇性循环动荷载模型,考虑孔压消散与土层沉降的耦合效应,建立了地铁荷载-隧道-饱和黄土地层的二维有限元模型,分析了饱和黄土地层在地铁运行过程中的长期沉降规律和影响因素,并预测了长期沉降的影响范围、沉降大小及趋于稳定的时间。
[Abstract]:Ground subsidence, differential settlement and secondary problems are one of the important effects of long-term operation of subway. In the next few years, urban track construction will be carried out on a certain scale in the loess region of western China. Taking Xi'an Metro as an example, most of the positive sections are below the groundwater level, which belongs to saturated loess with poor mechanical properties. The influence of subway load on the accumulated deformation of the ground can not be underestimated. At present, there are few dynamic constitutive models considering the structural characteristics of saturated loess, anisotropy and cyclic load characteristics of subway. In this paper, a new soil dynamic constitutive model is established considering the influence of these three factors. And it is applied to the analysis of the settlement characteristics of the subways around the tunnel. The results are as follows: (1) the structural factors of soils are divided into isotropic structural factors (Di) and anisotropic structural factors (Dr,). The anisotropic structural damage is assumed to be anisotropic Zhang Liang on the boundary surface. And critical state line slope. A rotation hardening rule considering anisotropic structural effects is established. At the same time, the law of isotropic hardening considering the influence of isotropic structural damage is adopted. (2) considering the cyclic loading and unloading effect and the first two hardening laws, the motion hardening law of the mapping center is established. It is assumed that when the loading direction changes, the mapping center will move to the reverse point of the stress, and the motion hardening will occur with the first two hardening processes of the boundary surface. Based on the Dafalias boundary surface model and the above three hardening rules, a dynamic boundary surface constitutive model of saturated loess considering anisotropic, structural and cyclic dynamic loads is established. The model parameters are classified, and the physical meaning and determination method of each parameter are described in detail. (3) the boundary surface model of this paper is compiled into UMAT subroutine, and the indoor motion of saturated loess specimen is simulated by ABAQUS finite element software. In the static triaxial test process, the rationality of the text construction model and the UMAT subroutine is verified by the consistency between the numerical simulation results and the indoor test results. (4) based on the UMAT subroutine and the intermittent cyclic dynamic load model established, Considering the coupling effect of pore pressure dissipation and soil layer settlement, a two-dimensional finite element model of underground load-tunnel saturated loess layer is established, and the long-term settlement law and influencing factors of saturated loess layer in the course of subway operation are analyzed. The influence range, the settlement size and the time of stabilization of the long-term settlement are predicted.
【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU444;TU43
本文编号：2201766
[Abstract]:Ground subsidence, differential settlement and secondary problems are one of the important effects of long-term operation of subway. In the next few years, urban track construction will be carried out on a certain scale in the loess region of western China. Taking Xi'an Metro as an example, most of the positive sections are below the groundwater level, which belongs to saturated loess with poor mechanical properties. The influence of subway load on the accumulated deformation of the ground can not be underestimated. At present, there are few dynamic constitutive models considering the structural characteristics of saturated loess, anisotropy and cyclic load characteristics of subway. In this paper, a new soil dynamic constitutive model is established considering the influence of these three factors. And it is applied to the analysis of the settlement characteristics of the subways around the tunnel. The results are as follows: (1) the structural factors of soils are divided into isotropic structural factors (Di) and anisotropic structural factors (Dr,). The anisotropic structural damage is assumed to be anisotropic Zhang Liang on the boundary surface. And critical state line slope. A rotation hardening rule considering anisotropic structural effects is established. At the same time, the law of isotropic hardening considering the influence of isotropic structural damage is adopted. (2) considering the cyclic loading and unloading effect and the first two hardening laws, the motion hardening law of the mapping center is established. It is assumed that when the loading direction changes, the mapping center will move to the reverse point of the stress, and the motion hardening will occur with the first two hardening processes of the boundary surface. Based on the Dafalias boundary surface model and the above three hardening rules, a dynamic boundary surface constitutive model of saturated loess considering anisotropic, structural and cyclic dynamic loads is established. The model parameters are classified, and the physical meaning and determination method of each parameter are described in detail. (3) the boundary surface model of this paper is compiled into UMAT subroutine, and the indoor motion of saturated loess specimen is simulated by ABAQUS finite element software. In the static triaxial test process, the rationality of the text construction model and the UMAT subroutine is verified by the consistency between the numerical simulation results and the indoor test results. (4) based on the UMAT subroutine and the intermittent cyclic dynamic load model established, Considering the coupling effect of pore pressure dissipation and soil layer settlement, a two-dimensional finite element model of underground load-tunnel saturated loess layer is established, and the long-term settlement law and influencing factors of saturated loess layer in the course of subway operation are analyzed. The influence range, the settlement size and the time of stabilization of the long-term settlement are predicted.
【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU444;TU43
【参考文献】
相关期刊论文 前10条
1 闫维明;张yN;任珉;冯军和;聂晗;陈建秋;;地铁运营诱发振动实测及传播规律[J];北京工业大学学报;2006年02期
2 吴义祥;工程粘性土微观结构的定量评价[J];中国地质科学院院报;1991年02期
3 韩日美;;西安地铁黄土隧道工程特性分析及对策[J];都市快轨交通;2010年06期
4 王兰民;西部大开发中的黄土地震灾害问题[J];地学前缘;2001年01期
5 林杜军;西安市近期饱和黄土的工程地质特征[J];地质灾害与环境保护;1994年01期
6 周尚国;;黄土隧道的主要地质灾害类型[J];地质与勘探;2007年02期
7 王志强;;甘肃引洮供水工程饱和黄土工程地质研究[J];工程地质学报;2005年04期
8 王国欣;肖树芳;;土结构性本构模型研究现状综述[J];工程地质学报;2006年05期
9 胡伟;韩建刚;;结构性饱和黄土动力特性试验研究[J];工程地质学报;2009年05期
10 傅世法;;论饱和黄土[J];工程勘察;1982年01期
相关博士学位论文 前1条
1 袁俊;城市轨道交通隔振减振机理及措施研究[D];西安建筑科技大学;2010年
，本文编号：2201766
本文链接：https://www.wllwen.com/guanlilunwen/chengjian/2201766.html
