大型基础下层状地基静力变形性状研究

发布时间：2019-03-15 18:16

【摘要】：大型基础下层状地基静力变形性状分析是土木工程领域中的常见类型问题,该类问题主要考虑土的本构关系、土的物理力学性质、基底附加应力的空间分布状况及传递过程等。随着高层建筑和超高层建筑的不断增多,基底作用荷载和基础尺寸不断加大,基础形式多变,特别是对于一些大型、复杂、重要的基础,如何计算和完整描述大型基础下层状地基土的静力变形性状成为研究者们一直致力解决而又尚未很好解决的问题。本文基于网格系统分层法思想,根据Mohr-Coulomb弹塑性本构模型对基底沉降计算公式中的压缩模量进行弹塑性修正,建立大型基础下层状地基竖向变形数学计算模型,并基于MATLAB软件平台自行编写SSBSMC计算程序,实现大型基础下层状饱和地基土变形计算。最后,应用SSBSMC程序对辽宁省博物馆新馆进行地基土变形计算分析,同时应用ABAQUS有限元分析软件及FLAC3D有限差分分析软件进行相同工况的数值模拟计算,通过计算结果相互校验来验证SSBSMC程序计算结果的合理性。结果表明,应用SSBSMC计算程序进行大型基础下层状饱和地基土变形计算是合理可行的,且计算最大沉降量和寻找最大沉降发生点时,不存在盲目性,计算结果直观；土体压缩模量可通过刚度矩阵由压缩模量定义推导得出,当土体处于弹性状态时,压缩模量仅与变形模量和泊松比有关,但当土体进入塑性状态,压缩模量不仅与变形模量和泊松比有关,还与土体当前竖向应力,侧压力系数,粘聚力以及内摩擦角有关；实际工程计算显示在地基土层越深处,附加应力值越小,分布越均匀,且应力等值线圆心逐渐向基础中心趋近；大型基础下地基最大竖向变形并不一定发生在基础中心点或最大荷载处,因此,单点计算基础某一点处的基底沉降存在一定程度的安全隐患。
[Abstract]:The analysis of static deformation behavior of large-scale foundation is a common problem in the field of civil engineering, which mainly considers the constitutive relation of soil, the physical and mechanical properties of soil, the spatial distribution of additional stress on the base and the transfer process, etc. With the increasing number of high-rise buildings and super-high-rise buildings, the load and size of the foundation are constantly increasing, and the foundation forms are changeable, especially for some large, complex and important foundations. How to calculate and completely describe the static deformation behavior of large-scale foundation subsoil becomes a problem that researchers have been trying to solve but have not solved very well. In this paper, based on the idea of grid system layered method and Mohr-Coulomb elasto-plastic constitutive model, the elastic-plastic modulus of the foundation settlement calculation formula is modified, and the mathematical model of vertical deformation of large-scale foundation is established. Based on the MATLAB software platform, the SSBSMC program is compiled to calculate the soil deformation of the saturated foundation in the lower layer of the large-scale foundation. Finally, the SSBSMC program is used to calculate and analyze the ground soil deformation in the new museum of Liaoning Province. At the same time, the finite element analysis software ABAQUS and the finite difference analysis software FLAC3D are used to carry out the numerical simulation calculation under the same condition. The rationality of the calculated results of SSBSMC program is verified by checking the calculated results with each other. The results show that it is reasonable and feasible to use the SSBSMC program to calculate the deformation of large-scale foundation saturated subsoil, and there is no blindness in calculating the maximum settlement amount and finding the maximum settlement point, and the calculation results are intuitionistic. The compression modulus of soil can be derived from the definition of compression modulus by stiffness matrix. When the soil is in elastic state, the compression modulus is only related to the deformation modulus and Poisson's ratio, but when the soil enters the plastic state, the compression modulus is only related to the deformation modulus and Poisson's ratio. The compression modulus is not only related to the deformation modulus and Poisson ratio, but also to the current vertical stress, lateral pressure coefficient, cohesion and internal friction angle. The actual engineering calculation shows that the more deep the soil layer is, the smaller the additional stress value is, and the more uniform the distribution is, and the closer the center of the stress contour circle is to the center of the foundation. The maximum vertical deformation of the foundation does not necessarily occur at the center of the foundation or the maximum load under the large-scale foundation. Therefore, the settlement of the foundation at a certain point of the foundation can be calculated by a single point and there is a hidden danger of safety to a certain extent.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU470

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