管袋坝接缝管路处渗透成拱的颗粒流模拟

Particle Flow Simulation of Soil Arching Effect of Channel of Joint among Sand-Filled Tubes under Seepage Forces

管袋坝接缝管路处是管袋坝体的薄弱部位,易引发渗透破坏,使吹填土体眼管路接缝渐进性流出.经试验可知在较低的渗透坡降作用下,土体可以在孔口形成土拱.采用PFC颗粒流数值模拟软件来研究管袋坝接缝管路处土体在渗透作用下的成拱效应,得出对应不同摩擦系数的吹填土体成拱的临界渗透坡降.从细观角度揭示了既有竖向位移又有侧向位移情况下的土体成拱过程.经研究可知,临界渗透坡降J随摩擦系数f的增大而增大,且有效拱厚随吹填土的摩擦系数f的增大而减小.

The channel because of the loss of s of joint is the weakness part among sand-filled tubes. It may lead the seepage failure oil along the channel under seepage forces. As the test shows, the soil could form arch with low seepage gradient. By conducting a series of numerical simulation with the particle flow code（PFC） for various material factors, the critical hydraulic gradient has been gotten; and the forming process of the soil arching has been shown. The result displays that the critical hydraulic gradient J grows with the friction coefficient f of soil; while the thickness of the soil arching decreases.