关键词: 滑坡, 稳定性, 渗流, 渗透力, 孔隙水压力, 设计规范

Abstract:

The seepage flow is one of the critical issues to the stability of landslide. In recent years, how to correctly reflect the effect of seepage force during the stability analysis of loose accumulational landslides has been the focus of geotechnical engineering. Certain Chinese design codes, which considered the effect of seepage flow, have a prominent problem in redundant computation of seepage force and pore water pressure. Based on the theory of hydromechanics, this paper has proved that the resultant force of seepage force and buoyant force is identical to that of ambient pore water pressure. Not only in steady seepage, but also unsteady seepage, the equivalent principle is tenable. As a special case, the proof process of this equivalent principle for loose accumulational landslide in seepage flow condition is suggested. This paper also proves the superiority of the calculation method using seepage force in a simple flow net condition, as well as the necessity of concerning the effect of seepage force and buoyant force in the calculation of the sliding force for landslides. This paper has revised the methods of stability analysis and sliding force calculation for the design codes. Furthermore, the impact of the deviation effect for certain design codes have been qualitative and quantitative evaluated. Finally, an engineering example illustrates that the result of the design thrust and the construction cost of landslide support project, which are given by unrevised design codes, is 5 % -or-less higher than necessary.

Key words: landslide, stability, seepage flow, seepage force, pore water pressure, design code