半刚性基层振动压实时的下承层动力响应分析

Analysis of dynamic stress response of lower course by moving-vibrating compaction on semi-rigid base

为判断半刚性基层振动压实能否造成下承层的早期破坏,对半刚性基层在移动—振动压实荷载作用下的下承层动态应力响应进行分析。将振动压路机对压实层施加的作用力简化成周期性变化的矩形均布压力,采用移动—振动荷载模型模拟振动压路机在振动压实过程中对压实层施加的作用,并对该振动压实荷载利用APDL语言编制相应的分析程序,实现了在有限元模型上的施加与求解。采用三维有限元瞬态动力分析方法以及AN SYS有限元程序,计算、分析半刚性基层在振动压实作用下的下承层的动态应力响应,建立了一种振动压实荷载作用下的路面结构层动态应力响应分析方法。算例显示,在下基层施工后7 d,振动压实上基层时下承层动态拉应力峰值接近下承层的极限抗拉强度,可能会出现产生早期破坏,从而表明在半刚性基层振动压实时进行施工荷载与施工时机控制是必要的。

The dynamic stress response of the lower course by moving-vibrating compaction on semi-rigid base was analyzed to judge whether it caused early wreckage to the lower course. The pressure of vibrating road roller on the compacted course was predigested to cyclical and rectangle uniform pressure. A moving-vibrating load model was used to simulate the load of vibrating road roller during compacting course, and the load was applied and solved with APDL based on fini-element model. 3D fini-element transient dynamic method and ANSYS fini-element program were used to calculate and analyze the dynamic stresses of the lower course while vibrating compaction on semi-rigid base. So a method of analyzing dynamic stresses of pavement structure under vibrating compaction was built. The calculation example shows that the peak value of dynamic tensile stress on lower course by vibrating compaction approaches the tensile strength of this course which may cause early wreckage to the lower course in 7d, meanwhile it also shows the necessity of control of construction load and construction time during vibrating compacting on semi-rgid base.