从土坡稳定的角度出发,基于强度折减原理,采用饱和非饱和渗流应力耦合方法,综合分析河堤岸坡内在因素和外界动力因素对窝崩形成的作用,探讨窝崩形成机理.结果表明:饱和非饱和渗流应力耦合方法计算的窝崩最小安全系数明显小于非耦合方法;窝崩的本质是岸坡土体在各种不利因素的组合作用下发生的剪切破坏;黏聚力及内摩擦角是防止窝崩的有利因素,而岸坡坡角、岸坡内外水位差、河流侵蚀等是诱发窝崩的不利因素;岸坡坡比是防止窝崩的控制性因素.
From the viewpoint of slope stability,the influences of the internal and external factors of riverbanks on the formation of their arc collapse were comprehensively analyzed based on the shear strength reduction principle by means of the saturated-unsaturated seepage stress coupling method.The arc collapse mechanism for the riverbanks was discussed.The results indicate that the minimum safety factor calculated by the saturated-unsaturated seepage stress coupling method is clearly smaller than that by the uncoupling methods.The essence of the arc collapse of riverbanks is the shear damage of soil under various unfavorable influence factors.The cohesion and friction angle are the favorable factors to avoid arc collapse of riverbanks,while the slope ratio,water level difference and river erosion are the unfavorable factors.However,the soil slope ratio is the dominant factor for the arc collapse of riverbanks.