南方低温条件下路基冲击动力特性模型试验

The model experiment for dynamic characteristics of the roadbed in low temperature environment of southern China

选取南宁河流相沉积土制作大尺寸路基模型,其尺寸为1.60 m(长)×1.45 m(宽)×1.00 m(深),分层夯实过程中初始含水量不变,温度均匀。利用环境发生器模拟气候条件,将环境发生器内温度分别设为0℃及-5℃,并持续作用。通过对路基模型中不同位置的温度和土压力的测试与分析,研究在冲击荷载作用下的路基土的动力响应。研究结果表明,路基动应力曲线沿深度的变化规律是呈幂函数规律变化,在模型深度10 cm到20 cm处土压力衰减快,低温的持续作用对路基的影响是沿深度方向逐渐变小,且当路基模型内的温度高于10.1℃时,路基中的土压力与温度相关性小,路基土温度低于10.1℃时,土压力峰值随着温度的降低而逐渐增大。

A large scale model of 1.60 m（length）×1.45 m（width）×1.00 m（height） was used to study dynamic characteristics of the roadbed in low temperature environment of southern China.The model had constant initial water content and was kept in homogeneous temperature during superficial compaction.Environment temperature was set at 0 ℃ and-5 ℃ when the model was subjected to dynamic forces.Temperature and earth pressure in the model were measured during the test.The results show that the earth pressure distribution along depth direction varies as a power function;the impact energy has a linear relationship with the earth pressure;the earth pressure decays rapidly between 10 cm and 20 cm from top of the model;the influence of low temperature on roadbed decreases with the increase of depth;the earth pressure has little relation with temperature when it is above 10.1 ℃;and the earth pressure increases with the decrease of temperature when it is below 10.1 ℃.