动荷载下桩承式路堤的承载特性及机制研究

发布时间：2018-06-06 23:18

本文选题：桩承式路堤 + 动荷载　；参考：《岩土力学》2014年11期

【摘要】：对于桩承式路堤作用效应的研究目前主要侧重于对静荷载作用下桩土应力比和土拱效应等,较少考虑动荷载的影响,而车辆运行产生的动应力会对路堤中的土拱产生一定的影响,进而影响桩承式路堤的整体性能。为了分析静、动荷载作用下桩承式加筋路堤的性能变化,采用可视化模型试验和颗粒流数值模拟相结合的方法,对桩承式路堤在静载和动载下的应力传递和变形性状进行研究,分析动载作用下填土高度、桩帽、桩距、加筋形式、荷载频率的影响。试验结果表明,在动载下无筋路堤的桩顶的应力减小,而桩间的应力和位移增大,并且变化的幅度均比加筋路堤大,加筋材料的设置有利于减小动载的影响效应,但不同加筋形式下桩承式路堤的工作性状有所不同,受动载影响程度的大小主要与土拱效应的强弱有关。设置双层加筋时,因加筋材料与周围砂土形成半刚性平台,土拱效应减弱,故受动载影响的程度最小,单层加筋时,格栅设于桩顶上方10 cm比格栅置于桩顶受动载影响的程度明显减小,颗粒流的模拟结果验证了以上结果,并且进一步得出随荷载频率的增加、填土高度与桩净距的减小,动载的影响效应增大的结论。
[Abstract]:At present, the study of pile-supported embankment effect mainly focuses on the pile-soil stress ratio and soil-arch effect under static load, and less on the effect of dynamic load. The dynamic stress caused by vehicle operation will affect the soil arch in the embankment and then affect the overall performance of the pile-supported embankment. In order to analyze the performance change of pile-supported reinforced embankment under static and dynamic loads, the stress transfer and deformation behavior of pile-supported embankment under static and dynamic loads are studied by means of visual model test and numerical simulation of particle flow. The influence of filling height, pile cap, pile spacing, reinforcement form and load frequency are analyzed. The test results show that the stress at the top of the unreinforced embankment under dynamic load decreases, but the stress and displacement between the piles increase, and the amplitude of the change is larger than that of the reinforced embankment. The setting of reinforced material is helpful to reduce the effect of dynamic load. However, the working behavior of pile-supported embankment is different under different reinforcement forms, and the influence degree of dynamic load is mainly related to the strength of soil arch effect. When two layers of reinforcement are installed, the soil arch effect is weakened because the reinforced material forms a semi-rigid platform with the surrounding sand, so it is the least affected by the dynamic load, and when the reinforcement is single layer, The effect of dynamic load on the top of the pile is obviously reduced when the grille is located 10 cm above the top of the pile. The simulation results of particle flow verify the above results, and further show that with the increase of the load frequency, the height of the fill and the net distance between the pile and the soil are decreased. Conclusion that the effect of dynamic load is increased.
【作者单位】：扬州大学建筑科学与工程学院;同济大学地下建筑工程系;
【基金】：国家自然科学基金(No.51278446,No.50908198)
【分类号】：U416.12

【参考文献】