Studies on wave impeding block (WIB) procedure for vibration reduction

本课题首先进行了高速列车诱发地面振动的计算机模拟。考虑到列车的几何形状（车轴距离和车段连接），用一组不同频率的调和运动函数来假设轨道载荷。此外，轨枕距离等振动因素对新干线横向振动的周期性有重要影响，因此对新干线运行实测数据进行了逆分析。采用作者提出的2.5维有限元-边界元法进行分析。因此，模拟地面振动可以很好地预测沿振加速度值（VAL）的衰减。其次，从计算机仿真的角度讨论了高速列车引起的铁路沿线地面振动及其抑制措施。从波在层状土中的传播原理出发，对轴载列车系统的模拟地面振动进行了解释。根据所获得的信息，对安装前后的波场进行了X-WIB减振率的演示。再次，采用一套土柱结构进行了WIB的现场施工，并测量了减振效果。为了验证上述结果对新干线振动的模拟效果和WIB程序的减振效果，还进行了相应的计算机仿真。

This research project first has dealt with the computer simulation of the high-speed train induced ground vibration. The track loading is assumed by a set of harmonio moving function of different frequencies in view of a train geometry (axle distances of a car and connection of cars). Besides, sleeper distances and other vibration factors involved are of essence for the periodicity of alongside vibration so that an inverse analysis is introduced of the measured data for the Shinkansen running. The 2.5 dimensional FEM-BEM method developed by the authors is used for the analysis. Thus simulated ground vibration results in a good prediction for the attenuation of alongside vibration acceleration value (VAL).Next, lineside ground vibrations induced by high-speed trains and the mitigation measure are discussed from the computer simulation. The simulated ground vibration due to a train system of axle loads is interpreted from the knowledge of wave propagation in layered soil. The vibration reduction rate by the proposed X-WIB based on thus obtained information is demonstrated for the wave field before and after the installation.Thirdly, a field construction of a WIB is conduced by a set of soil column construction and the effect of the vibration reduction is measured. The corresponding computer simulation is also carried out in order to validate the aforementioned results for the Shinkansen vibration simulation and the reduction effect by the WIB procedure.