桩板结构路基动力模型试验研究

桩板结构路基是高速铁路无碴轨道的一种新的路基结构形式,基于Bockingham π定理,采用量纲分析方法,确定了桩板结构路基模型的动力相似常数,通过室内大比例动态模型试验研究,分析了在循环加载的条件下浸水前、后桩板结构路基的动态力学特性.试验结果表明,路基动应力沿深度逐渐衰减,激振频率对动应力的影响不太明显;路基边坡浸水后,在相同加载频率下,动应力比浸水前略有增大;桩基加深了路基的动力影响范围,改善了路基土体部分的受力状态;桩底持力层受动力影响较大,是动力设计的关键环节之一.

Model experimental research on dynamic performance of pile-plank embankment

The pile-plank embankment is a kind of new-type of ballastless truck in high-speed railway. Based on the theorem of Bockingham ?, the dimensional analysis method is applied, and the dynamic model similitude constant of pile-plank embankment is determined. Dynamic characteristics of pile-plank embankment before and after soaking in water are analyzed by the large scale model test under dynamic loading. The test results indicate that dynamic stress of the soil decreases with the increase of vertical depth, and it is less affected by loading frequency. After the roadbed side-ascent soaking in water, at the same loading frequency, dynamic stress is slightly increased compared to embankment before soaking in water. Pile structure expands the depth of the dynamic response of roadbed and improves the stress of the roadbed soil. Bearing stratum at pile-bottom is greatly affected by dynamic loading; and it is one of the key of the dynamic design.