一种基床系数计算方法及其在反应位移法中的应用  

A method for calculating subgrade reaction coefficient and its application in reaction displacement method

作　　者：程新俊 许翔 景立平[2] 崔杰[3] 梁海安[1] CHENG Xinjun;XU Xiang;JING Liping;CUI Jie;LIANG Haian(School of Civil and Architectural Engineering,East China University of Technology,Nanchang 330013,China;Institute of Engineering Mechanics,China Earthquake Administration,Key Laboratory of Earthquake Engineering and Engineering Vibration of China Earthquake Administration,Harbin 150080,China;School of Civil Engineering,Guangzhou University,Guangzhou 510006,China)

机构地区：[1]东华理工大学土木与建筑工程学院,江西南昌330013 [2]中国地震局工程力学研究所中国地震局地震工程与工程振动重点实验室,黑龙江哈尔滨150080 [3]广州大学土木工程学院,广东广州510006

出　　处：《岩土工程学报》2023年第12期2604-2613,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金青年基金项目(52008081);国家自然科学基金重点国际(地区)合作研究项目(52020105002);国家自然科学基金地区项目(52168045)。

摘　　要：地下结构抗震分析中对基床系数的取值局限于经验值,没有反映地层在受震过程中的不利变形及土层埋深对基床系数的影响,存在一定计算误差。为考虑土层地震反应和土层埋深的影响,基于非饱和砂土场地振动台模型试验和土层一维剪切梁模型,分析了土层剪应力-位移演变规律,提出了考虑地震响应的非饱和砂土基床系数随土层深度变化的计算方法,结合地下结构抗震分析算例验证了计算方法的合理性和适用性。研究结果表明:土层剪应力-位移滞回结果受地震动频谱特性和输入地震动峰值(PGA)的影响;等效基床系数随土层埋深的增大而增大;提出的基床系数取值方法可以用于改进反应位移法,有效模拟不同埋深处地层对地下结构的约束作用,以动力时程分析为基准,相较于传统反应位移法,改进后的反应位移法在侧墙(误差2.11%)、中柱的弯矩(误差10.69%)、层间位移角(误差0.07%)计算精度上得到了提升。The value of the traditional subgrade reaction coefficient adopted in the seismic analysis of underground structures is always limited by the empirical one.The empirical value cannot reflect the adverse deformations of soil deposits and the effects of buried depth,thus a certain calculation error will be generated.The evolution rules of shear stress-displacement of sandy soil are analyzed on the basis of shaking table tests on an unsaturated sandy site and the one-dimensional shear beam model for soil layers,and then a model is proposed to calculate the subgrade reaction coefficient considering the seismic responses of the soil layers and buried depth.The reasonableness and applicability of the proposed method are verified through an example of seismic analysis of an underground structure.The test results indicate that the hysteretic characteristics of the shear stress-displacement of soil deposits are affected by the features of seismic spectrum and peak ground acceleration(PGA).The equivalent subgrade reaction coefficient increases with the increase of the buried depth.The proposed method can be used to modify the response displacement method for simulating the restraint effects of soil on underground structures.Based on the dynamic time-history analysis,the accuracies of bending moments of side wall,central column and story drifts obtained by the modified response displacement method are improved as compared to those of the traditional response displacement method,(with the calculation errors of 2.11%,10.69%,and 0.07%,respectively).

关 键 词：地下结构抗震 振动台模型试验 反应位移法 基床系数 变形模式 

分 类 号：TU354[建筑科学—结构工程]