【摘要】 基于传统的Boussinesq课题解答,利用集中荷载作用下半无限空间弹性路基中不同空间位置,且满足一定限制条件的点的应力应变状态的集合来表征单次行车荷载下路基岩土体内某一点加载、卸载全过程的应力、应变等力学响应,将动力学问题转化为准静力学问题,建立着眼于简单与实用的路基动力学行为分析模型。借助建立的模型探讨路基一个加载、卸载全过程的应力状态及其有效作用半径。研究表明,(1)路基单元体动正应力差(σz?σx)和(σz?σy)曲线表现为脉冲状,而(σx?σy)曲线为双峰状;(2)最大主应力σ1绕z轴可能突发大角度旋转,但与z轴交角则连续旋转180°,最小主应力σ3整体旋转特征不甚明显,中间主应力σ2方向变化规律性较差;(3)单次交通荷载对路基路面系统的有效作用半径确定为10 m,影响范围确定为以荷载作用点为圆心,以10 m为半径的空间半球体。最后,利用原位监测数据对确定单次交通荷载的有效作用半径为10 m的合理性进行验证。更多还原

【Abstract】 Based on the classical Boussinesq analytical solutions,a set defined by stress and strain state of points,when subjected to concentrated load,with varied spatial location in semi-infinite elastic subgrade and constrained by certain conditions,is employed to characterize the stress and strain state of a fixed point in the subgrade during the loading-unloading process induced by a single vehicle load.Dynamics,consequently,is transformed into quasi-statics,and analysis model,which is supposed to be convenient and practical for verifying subgrade dynamic behaviors,is established.Stress state and effective working radius are approached and determined during a loading—unloading process in subgrade.Results indicate:(1) curves of dynamic normal stress differences() and() are pulse shape,while() changes in a twin peak manner;(2) the maximum principal stress might whirl abruptly about z axis,and the angle intersected with z axis rotates gradually and continuously by 180°;the orientation of minimum principal stress turns in a relatively smooth pattern and its rotation features are less remarkably;while the intermediate principal stress direction alters elusively;(3) effective working radius,which represents the limit of impacts exerted by a single vehicle loads on subgrade,pavement system,is suggested to a length of 10 m,and the influenced area can be considered as a semi-sphere with a radius of 10 m and whose center sited at the point of load.At last,the validity of effective working radius,which is defined by 10 m under one vehicle loading,is specified by in situ monitoring data.更多还原