基于土体振动能量吸收特性的层状路基缩尺模型尺寸效应研究  

Size effect of scale models for layered subgrades based on soil's vibration energy absorption characteristics

作　　者：曹海莹[1] 刘云飞[1] 李雨浓[1] CAOHaiying;LIUYunfei;LI Yunong(School of Civil Engineering and Mechanics,Yanshan University,Qinhuangdao 066004,Chin)

机构地区：[1]燕山大学建筑工程与力学学院,河北秦皇岛066004

出　　处：《振动与冲击》2018年第1期77-84,共8页Journal of Vibration and Shock

基　　金：国家自然科学基金资助项目(51308486)

摘　　要：针对缩尺模型试验的尺寸效应问题,以车辆荷载作用下的上硬下软型双层路基为研究对象,从揭示动应力衰减规律角度出发,选取土体能量吸收系数作为表征尺寸效应的参量;基于不同比例计算模型的数值模拟结果,给出动应力代表值沿深度的衰减公式,并依据均质土体能量吸收系数与模型比例的拟合关系,构建出硬、软土层内的尺寸效应响应方程;根据动应力界面传递系数与模型比例的函数关系,并引入无量纲"土层界面能量吸收系数",推导得出土层界面过渡段的尺寸效应响应方程;借助现场监测数据和室内模型试验,验证了尺寸效应响应方程的可靠性。研究表明:在振动频率取1~5 Hz前提条件下,运用缩尺模型试验结果和尺寸效应演化规律能够反演原型试验的工况,相关成果对工程实际有一定的指导意义。Aiming at inspecting the size effect of scale models in tests,and considering a two-layered subgrade with upper dry crust and lower weak subsoil under vehicle load,as a study object,the soil＇s energy absorption coefficient was selected as a characterization parameter for analysing the size effect from the view of revealing dynamic stress attenuation behaviors. On the basis of numerical simulation results of different scale calculation models,the attenuation expression for the dynamic stress＇ s representative value along depth was obtained and the response equation for describing the size effect was built in hard and soft soil layers according to the fitted relationship between the model scale and homogeneous soil ＇s energy absorption coefficient. The response equation for describing the size effect at the transition section was derived based on establishing the functional relation between the dynamic stress ＇s interface transfer coefficient and model scale,and introducing the dimensionless energy absorption coefficient at soil interface. The reliability of the response equations was validated by the field monitoring data and indoor model tests. The results show that the working condition of the prototype experiment can be infered by applying the test results of scale models and the evolution of size effect,under the premise of vibration frequency being 1 Hz to 5 Hz. The relevant results have some guiding meaning for actual projects.

关 键 词：层状路基 尺寸效应 数值模拟 缩尺模型 能量吸收系数 

分 类 号：TU435[建筑科学—岩土工程]