潜没式高趾墙土压力与稳定计算方法

潜没式高趾墙是许多混凝土面板堆石坝中重要的水工建筑物,其墙背堆石体的表面水压力不是均布荷载,且作用线与竖直向存在一非零夹角,与多数挡土墙设计规范中竖直向下的均布荷载差别很大,不能直接套用规范给出的公式计算其承受的土压力。根据库伦土压力理论,探讨了潜没式高趾墙主动和被动土压力的计算方法,并运用案例证实了通过改变滑裂面倾角和数值试算方法确定土压力的必要性;分析了需进行高趾墙抗滑稳定分析的两类特定情形,即水平水压力低于主动土压力水平分量或水平水压力高于被动土压力水平分量(若水平水压力介于两者之间,则不存在抗滑稳定问题)。文中还探讨了高趾墙抗倾覆分析需进一步研究的问题及可行方法。

Calculation method for earth pressure and stability of high submerged toe walls of concrete faced rockfill dams

High submerged toe walls are important hydraulic structures in many concrete face rockfill dams. The surface load exerted upon the backfilled rockfill materials is the hydraulic pressure， which is neither evenly distributed nor vertically downward. This load condition is evidently different from that given by designing codes of the retaining walls， in which the surface load is generally vertically downward and evenly distributed. Therefore， evaluating the earth pressure according to such designing specifications may give improper results. In this study， based on Coulomb′s earth pressure theory， the methods for evaluating the active earth pressure and the passive earth pressure on the high submerged toe walls are discussed. The necessity of numerical calculation of the earth pressures by changing the inclination angle of the slipping mass over its possible range is clarified by simple case studies. Two specific conditions that require further stability analysis for the high toe walls are also fixed， namely the horizontal water pressure is less than the horizontal component of the active earth pressure or more than the horizontal component of the passive earth pressure on the high toe walls (the sliding resistance stability problem doesn′t exist when the horizontal water pressure is between the horizontal component of the active earth pressure and the horizontal component of the passive earth pressure on the high toe walls). Moreover， the problems regarding the evaluation of the overturn moment of the high toe walls and the feasible approach to solve the problems are pointed out in the paper.