循环荷载作用下岩溶路基土的动力特性试验研究

在现场调查的基础上, 针对高铁通过岩溶区域典型土样, 开展了模拟高铁循环荷载作用下的动三轴试验, 研究了高速列车运行荷载作用下岩溶路基土的动力特性。结果表明, 振动前期土体动应变随着振动次数的增加几乎呈线性增大, 振动后期动应变呈非线性增加, 应变增量逐渐减小, 并最终趋于稳定。随着振动次数的增加, 土体中孔隙水压力逐渐增大, 但总体增加幅值不大; 土体破坏后, 即使振动次数继续增加孔隙水压力也不再增大。因此, 在岩溶地区进行高铁工程建设, 一定要分析不同设计时速产生的高速循环荷载对路基稳定性的影响, 采取有效防治措施, 确保工程建成后列车的正常运营和行车安全。

Experimental Study on Dynamic Characteristics of Subgrade Soil under Cyclic Load in Karst Area

On the basis of on-site investigation, dynamic triaxial test was conducted by simulating the cyclic load of high-speed rail running through the typical subgrade soil in Karst area for obtaining the dynamic characteristics of subgrade soil. Results showed that the dynamic strain increases linearly with the vibration frequency at the first stage, then turning to be nonlinearly with the strain increment gradually decreased to be stable at last. The pore water pressure in the soil increased with an increase in frequency of vibration, although the total rise rate being slow. But it failed to increase further even vibrations frequency continued to increase once the soil was destructed. Therefore, during the construction of a high-speed railway in Karst area, the effect of cycle load of train with different speed per hour on the roadbed stability should be analyzed and effective prevention measures must be taken, so as to ensure the normal operation and safety running of the train after project completion.