清连公路沿线坡面冲刷研究

A study on slope surface erosion along qing-lian expressway

坡面冲刷是我国南方花岗岩地区铁路公路沿线路堑边坡的主要工程地质问题。按不同分类标准 ,可分为片蚀、沟蚀与坍塌 ;推移质冲刷与悬移质冲刷 ;裸坡冲蚀与潜蚀等不同形式。路堑开挖剥离‘山皮’是坡面冲刷严重的直接原因 ,冲刷在坡面上具有明显的纵向分带性质。在坡面径流作用下 ,土物会受到拖曳力、上举力、渗透压力、粒间离散力等多种力的综合作用。由坡面流能量、能量损失、传递及其平衡得出了坡面流对坡面上土物的拖曳力。由冲刷过程中力的平衡条件 ,得出了坡面上土物的失稳起动拖曳力。由能量守恒原理 ,分别得出了坡面流推移质冲刷能力和悬移质冲刷能力 ,由此得到坡面冲刷强度。

To the cutting slopes composed by granite residual soil along railway and highway in southern China, the primary engineering geological problems is slope surface erosion. When a line goes through granite region, it needs cutting natural slopes in order to form roadcut or lower their grades, which destroys the original geotechical conditions and related environmental conditions. It results in a transition during a short time from relatively slow erosion to accelerated process. Slope erosion can be classified into erosion with bed load transport, erosion with suspension transport, etc. There are some forces acting on soils in slope overland flow, they are drag force, lift force, seepage force, dispersion force, etc. the stability of soil particles on the slope surface depends on the above forces acting on them. It can get the drag force according to flow energy, energy loss, energy transfer and its balance. It can get the incipient motion conditions according to the balance among the forces. The slope erosion intensity is just the capability of slope surface runoff to carry soil particles. It includes two parts:the bed load and the suspended load. based on the theories of sediment transport ation, the bed load yield and the suspended load yield can be obtained respectively. Therefore it can get the total erosion yield.