液化场地桩－土－桥梁结构地震相互作用振动台试验数值模拟方法研究.docVIP

液化场地桩－土－桥梁结构地震相互作用振动台试验数值模拟方法研究 摘 要：直接针对大型振动台模型试验，建立液化场地桩－土－桥梁结构地震相互作用数值模拟的二维分析模型和计算方法。根据桩基平面应变假定，将空间桩体转换成平面板桩，并考虑桩的尺寸效应；基于桩截面节点位移协调条件和平衡力系等效原理，建立四结点梁单元刚度矩阵且对Timoshenko梁杆单元刚度矩阵进行增广修正，以考虑桩的横向尺寸影响桩周土位移场分布的尺寸效应。根据有效应力原理进行土动反应分析，采用满足Masing准则的修正双曲线模型描述土动力变形的本构关系，同时考虑因孔压上升造成土体软化而对土动力性能的影响，由迭代法处理土的动力非线性。采用并联弹簧－阻尼器模拟计算域人工边界，以考虑边界波的反射作用对体系动力反应的干扰和土粘滞阻尼的影响。采用逐步积分法计算体系的地震反应。通过与试验结果的对比分析，评估数值模拟的建模途径和计算方法的可靠性。 关键词：大型振动台模型试验；数值模拟；桩－土－桥梁结构地震相互作用；液化场地。 中图分类号：U442.55 文献标识码：A Numerical Simulation Method of Shaking Table Test on Earthquake Intraction of Pile-Soil-Bridge Structure in Liquefaction Site Abstract: Directly aiming at large-scale shaking table model test, the paper will establish two-dimension analysis model and numeration method on numerical simulation method of earthquake interaction of pile-soil-bridge structure in liquefaction site. Based on the assumption of plane strain of pile foundation and considering scale effect of pile, special pile bodies are transformed into plane sheet pile. According to the displacement harmony condition of pile section node and the equivalent principle of force system, the analysis model will set up four crunodes element stiffness matrix of beam cell and amend Timoshenko beam-pole stiffness matrix increasingly in order to consider the displacement field distribution of soil nearby the pile as a result of dimension effect of pile landscape orientation. Depend on soil dynamic response by effective stress theory, the amendatory hyperbolic model which accords with Masing rule is adopted to describe constitutive relation of soil dynamic deformation and the effect for soil intenerating caused by rise of pore water pressure on soil dynamic performance is taken into account through iteration method to deal with the problem of soil nonlinear momentum. Parallel spring-counterbuffer model is used to simulate artificial boundary in the computation region to consider the effect which derived from reflection of boundary wave on the interference of s