土—桩基—框架结构动力相互作用体系地震反应分析

发布时间：2018-07-21 11:45

【摘要】：土与结构动力相互作用问题是土木工程和地震工程领域中的热点、难点课题,由于地震发生的随机性与难以预测性,使得地震作用下土与结构动力相互作用的理论仍不完善。依托海城市中心医院工程,围绕地震作用下土与结相互作用关系进行深入研究,通过理论分析与数值模拟手段相结合,重点研究了桩土动力接触本构模型,构建了海城市中心医院工程地震反应有限元模型,分析了不同地震波作用影响下考虑土与结构相互作用的结构动力反应,给出了一种合理实用的高层建筑土与结构相互作用地震反应分析的简化方法。具体工作如下： (1)对海城市中心医院工程结构进行合理简化,将地下结构楼板简化为刚性楼板；将地上结构等效成梁柱体系,采用质量与刚度折减方法将楼板简化成梁系；确定了土体、结构在有限元分析中的单元模型与本构模型,构建了合理的考虑在地震作用影响下土与结构相互作用有限元模型,同时选定用增量迭代混合法求解非线性动力方程。 (2)分析ANSYS软件中的接触单元计算原理,针对其中缺陷,在考虑桩土分离、滑移效应的基础上,考虑动力作用中的基础提离效应,并引入阻尼成分考虑桩土动力接触中的能量损耗,给出了一种改进的二维和三维桩土动力接触本构模型,并推导了其相应的接触单元的单元刚度矩阵。随后进行了算例验证,说明优化的桩土动力接触本构模型可以应用在地震作用下桩土相互作用分析中,为后续的结构地震反应分析提供了必要的理论依据。 (3)采用优化后的桩土动力接触本构模型,建立考虑土与结构相互作用海城市中心医院工程的三维动力分析模型,模拟输入天津波、Taft波和人工波在不同加速度幅值作用下结构加速度、位移和地下结构应力变化以及地基土体应力的变化情况。得出对海城市中心医院工程结构地震反应影响最大的为天津波,其次为Taft波,影响最小的为人工波；整体结构在地震作用下的最大位移值符合《建筑抗震设计规范》(GB50011-2010)要求,具备较好的抗震性能。地上结构在地震作用下加速度值与位移值要大于地下结构,弯矩最大值出现在地下结构一层桩柱顶端与地下结构二层桩柱底端,是地下结构中安全系数最小处,需要引起设计人员足够重视。 (4)以考虑地震作用下土与结构相互作用的海城市中心医院工程三维有限元计算结果为依据,并参考《动力机器基础设计规范》(GB50040-96)中两层质-弹-阻模型,随后对两层质-弹-阻模型中的地基质量、抗剪刚度、土体模型自由度和阻尼比等因素进行修正,给出了修正的多层质-弹-阻模型,给出了地震作用下土与结构相互作用的地基基础简化分析方法。
[Abstract]:Soil-structure dynamic interaction is a hot and difficult problem in civil engineering and seismic engineering. Due to the randomness and unpredictability of earthquake occurrence, the theory of soil-structure dynamic interaction under earthquake is still imperfect. Based on the Haicheng central hospital project, the interaction between soil and soil under earthquake is studied in depth. The dynamic contact constitutive model of pile and soil is studied by combining theoretical analysis with numerical simulation. The finite element model of seismic response in Haicheng central hospital is constructed, and the structural dynamic response considering the interaction between soil and structure under the influence of different seismic waves is analyzed. A reasonable and practical simplified method for seismic response analysis of soil-structure interaction in high-rise buildings is presented. The specific work is as follows: (1) the engineering structure of Haicheng central hospital is reasonably simplified, the underground structure floor is simplified to rigid floor slab, and the above floor structure is equivalent to Liang Zhu system. The method of mass and stiffness reduction is used to simplify the beam system of floor slab, the element model and constitutive model of soil mass and structure in finite element analysis are determined, and the finite element model of soil-structure interaction under the influence of earthquake is constructed. At the same time, the incremental iterative mixing method is chosen to solve the nonlinear dynamic equation. (2) the principle of contact element calculation in ANSYS software is analyzed. Considering the defects, the pile-soil separation and slip effect are considered. Considering the foundation lift effect in dynamic action and introducing damping component into consideration of energy loss in pile-soil dynamic contact, an improved two-dimensional and three-dimensional pile-soil dynamic contact constitutive model is presented. The element stiffness matrix of the contact element is derived. A numerical example shows that the optimized pile-soil dynamic contact constitutive model can be applied to the pile-soil interaction analysis under earthquake. It provides the necessary theoretical basis for the subsequent structural seismic response analysis. (3) using the optimized pile-soil dynamic contact constitutive model, a three-dimensional dynamic analysis model considering the interaction between soil and structure is established for the Haicheng central hospital project. The structural acceleration, displacement, stress change of underground structure and the stress change of foundation soil are simulated under different acceleration amplitudes of input Tianjin wave Taft wave and artificial wave. It is concluded that Tianjin wave, Taft wave and artificial wave have the greatest influence on the seismic response of the engineering structure of Haicheng Central Hospital, and the maximum displacement value of the whole structure under earthquake action conforms to the requirements of the Code for Seismic Design of buildings (GB50011-2010). Good seismic performance. The acceleration and displacement values of the above ground structure under earthquake are greater than those of the underground structure, and the maximum bending moment appears at the top of the pile column of the first story of the underground structure and the bottom of the two-story pile column of the underground structure, which is the minimum safety factor in the underground structure. It is necessary for designers to pay enough attention to it. (4) based on the three-dimensional finite element calculation results of Haicheng central hospital engineering considering the interaction between soil and structure under earthquake action, With reference to the two-layer mass-elastic-resistive model in the Code for Design of dynamic Machine Foundation (GB50040-96), the factors such as foundation mass, shear stiffness, degree of freedom of soil model and damping ratio in the two-layer mass-elastic-resistance model are modified. A modified multilayer silt-elastic-resistance model is presented, and a simplified analysis method of soil-structure interaction under earthquake is given.
【学位授予单位】：辽宁工程技术大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU311.3;TU435

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