崩滑岩体对埋地管线横向冲击作用的数值模拟

采用离散元软件3DEC对高速下落岩体冲击地面、引起埋地管道动力响应的过程进行数值模拟,考察影响管道表面土压力和管道变形的主要因素.结果表明:冲击荷载作用下管道表面土压力分布非常不均匀,靠近管道顶部的区域是主要影响区,冲击作用面积是主要影响区范围的决定性因素;落体质量和冲击速度是影响管道表面最大土压力的主要因素,落体对管道表面土压力沿纵向的影响范围大致为冲击作用半径的2倍;落体速度相同时,落体质量对管道变形的影响比冲击作用面积更显著;增大管道埋深可以减小管道的冲击变形量;与采用较硬的黏土作为管沟填充料相比,无黏性砂填充时冲击荷载更容易引起管道发生较大变形.

Numerical simulation on response of buried pipeline induced by rock-fall transverse impaction

The 3DEC software was used to simulate the dynamic response of buried pipeline induced by rock-fall impaction, in order to investigate the main factors which influenced the soil pressure acted on the pipe surface and the deformation of pipe. The results indicate that the earth pressure at the pipe surface is extremely nonuniform, and the main influence range of impaction on the surface earth pressure is near the top of the pipe. The main influence range is determined by the real contact area in impaction. The mass and velocity of rock-fall are the primary factors influencing the maximal soil pressure on pipe surface. The influence range of impaction is approximate twice as large as the radius of impact area. If the rock-fall has the same impacting velocity, the mass of block has more influence on the damage of pipeline than the contact area, and the thicker covering soil could give pipe better protection under impacting loads. In comparison with using stiff clay as backfill soil, the pipe could produce more deformation than with sand backfilling under impact loading.