振动荷载下路基的能量耗散率空间分布规律的研究

为研究振动荷载作用下的路基内部的能量状态分布,基于Parseval定理,分别以动应变/加速度为变量,推导建立了周期性和非周期性的路基内振动信号的能量耗散率计算公式;根据土体的动力互易性原理,进行了振动荷载下路基动力响应现场试验,利用试验测试结果,分析研究了该路基的能量耗散率空间分布规律。研究结果表明:①能量耗散率沿深度方向和水平方向均呈指数衰减。能量耗散率沿深度方向衰减相比沿水平方向的衰减更为显著,深度方向衰减系数为水平方向衰减系数的2.5~3.0倍;②能量耗散率在不同深度处沿水平方向的衰减规律基本一致,而不同水平位置处沿深度方向的衰减规律不同。距离振动点越远,能量耗散率沿深度方向的衰减越缓慢;③在该试验条件下,振动路基的能量分布范围为水平方向1.5 m和深度方向0.45 m,能量分布的水平范围约为深度范围的3.3倍,能量分布区域在空间上呈扁平的“海鸥”状分布。

Spatial distribution of the energy dissipation rate in a subgrade under vibration load

In order to study the energy state distribution inside a subgrade under vibration load,based on the Parseval theorem,the calculation formula for the energy dissipation rate of the vibration signals in periodic and non-periodic subgrades was derived by using the dynamic strain/acceleration as variables.According to the principle of dynamic reciprocity of soil,the field test for subgrade dynamic responses under vibration load was carried out.The spatial distribution of energy dissipation rate in the subgrade was analyzed and studied by using the test results.The results show that①the energy dissipation rate decreases exponentially in both the depth direction and the horizontal direction.The attenuation of energy dissipation rate in the depth direction is more significant than that in the horizontal direction.The attenuation coefficient in the depth direction is 2.5 to 3.0 times of the attenuation coefficient in the horizontal direction.②The attenuation of the energy dissipation rate in the horizontal direction at different depth is basically consistent,and the attenuation in the depth direction at different horizontal position is different.The farther away from the vibration point,the slower the attenuation of energy dissipation rate along the depth direction.③Under the experimental conditions in the paper,the energy distribution range of the vibration subgrade is 1.5 m in the horizontal direction and 0.45 m in the depth direction,the horizontal distribution range of the energy is about 3.3 times greater than the depth range,and the energy distribution area presents a spatial flat“gull”shape.