基于振动性态和破坏相似的边坡振动台模型实验相似律  

Similitude for shaking table model test on side slope relating to dynamic characteristics and strength

作　　者：蒋良潍[1] 姚令侃[1] 王建[1] 

机构地区：[1]西南交通大学土木工程学院,四川成都610031

出　　处：《交通科学与工程》2009年第2期1-7,18,共8页Journal of Transport Science and Engineering

基　　金：国家重点基础研究发展计划(973计划)资助项目(2008CB425802);中国博士后科学基金面上资助项目(20070411163);高等学校博士点科研基金新教师项目资助课题(20070613011);西藏自治区交通厅科技项目(XZJTKJ2006-01)

摘　　要：鉴于岩土动态性质复杂及地震模拟振动台尺寸较大,边坡振动台模型实验采用原型工点采样岩土材料制成模型.模型实验相似律不仅应确保由共振频率与行波效应所体现的振动性态相似,同时应尽可能对变形破坏行为进行相似模拟,即做到破坏强度和应力水平相似.相似律关键在于保证原型、模型的按参考应变归一化后的应变比一致,因为岩土体本构关系呈软弹簧非线性,归一化应变比不仅决定对应的相对应力水平,更重要的是影响着共振频率.基于Mohr-Cou lomb破坏准则和双曲线动本构模型恢复力骨干曲线,提出在保持归一化的剪应变比一致条件下,兼顾振动性态和破坏相似的振动台模型实验相似律:由土体初始剪切模量随埋深的幂函数变化规律,按振动性态相似原则确定台面输入地震波波形的时间压缩比,再以岩土材料的强度参数(c,φ值)按破坏相似原则确定台面输入波形的幅值比,得到各主要物理量的相似律.Beause of the complexity of soil＇s dynamic characteristics and large size of earthquake simulation shaking table, side slope models on shaking table constructed by filling soils sample in-situ. The similitude for slope model test ought to reflect the similarity between model and prototype, especially resonant frequency, travelling wave effect and deformation failure behavior. Due to the soft-spring nonlinear behavior of soils, the key condition to determine similitude is keeping the same strain ratio, which expressed as strain normalized with the reference strains. Strain ratio not only determine the stress level, but also affects resonant frequency. Based on Mohr-Coulomb failure criterion, Hyperbolic Model of soils and the condition of keeping same strain ratio, similitude for large-scale earthquake simulation shaking table test of side slopes were proposed. The power function relationship of original shear modulus versus embedded depth to account, time scaling factor of input earthquake wave on shaking board were determined by similar resonant frequency, and acceleration amplitude factor of input wave was obtained by strength parameters （ cohesion c and internal friction angle φ） of soils.

关 键 词：边坡 振动台模型实验 相似律 归一化应变 初始剪切模量 时间压缩比 加速度幅值比 

分 类 号：U416.14[交通运输工程—道路与铁道工程]