不同服役环境下高速铁路膨胀土路堑基床振动特性模型试验

Model tests on vibration characteristics of cutting subgrade of expansive soil of express railways under different service environments

为研究铺设半刚性防水结构层的膨胀土路堑基床的振动特性,在实验室内进行1∶1大比例尺模型试验,对基床在干燥、降雨和地下水位上升3种服役环境下以4 Hz频率分别进行100×104次激振,监测路堑基床不同位置的加速度和速度响应。结果表明:在相同循环动力荷载作用下,服役环境对新型基床结构的振动加速度和速度大小具有显著影响,但对二者沿基床深度方向的衰减规律影响不大;与干燥服役环境相比,路基面的加速度和速度增长幅度在降雨服役环境下分别为35%和20%,地下水位上升时分别为45%和23%。

In order to study the vibration characteristics of cutting subgrade by using semi-rigid water-proof structural layer, 1:1 large-scale model tests are carried out. The cyclic loads with frequency of 4 Hz and excitation of 100 thousand times are imposed on the subgrade model under three kinds of service environments(dry, raining and underground water rising). The results show that under the same cyclic loads, the influence of service environments on velocity and acceleration of cutting subgrade is significant, but they have not obvious influence on their attenuation law in the vertical direction. Compared to that under the dry working condition, the increasing range of velocity and acceleration on subgrade surface is respectively 35% and 20% under the raining service environment, and 45% and 23% under the underground water rising service environment.