中文摘要：

引入变异因子,推导土体黏聚力沿深度线性变化时的边坡极限分析上限法相关公式,研究成层土不同分布情况下的稳定性,并对极限分析法与极限平衡法中的评价指标进行对比。结果表明：对于刚体转动破坏,当坡脚土层黏聚力不变时,随着变异因子的增大,滑面对应的张角增大,但滑面位置变动微小,稳定系数近似线性增加。稳定系数和安全系数随变异因子的改变呈现相同的变化规律,但安全系数的大小与边坡坡高、土体重度和黏聚力有直接关系;考虑土体变形时,变形区内由黏聚力变化引起的损耗率是对数旋转面上的一半;坡脚土层黏聚力保持不变时,极限承载力随着变异因子的增加近似线性增加;当坡脚土层黏聚力大于坡肩时,边坡的稳定系数、安全系数和极限承载力均比土层相反分布时的要大。表明边坡坡脚土层黏聚力过小更容易造成失稳,建议采取＂固脚强腰＂的防护措施以确保边坡稳定。

英文摘要：

By introducing the variation factor,the upper-bound limit analysis of slope stability was conducted while the soil cohesion varied linearly as the depth increased,the stability of the slope with different layer distributions was discussed,as well as different evaluation indexes in the limit analysis and limit equilibrium methods were compared.Result indicates that,as to rigid sliding,with the constant soil cohesion at the slope toe,the angle of the sliding surface and the stability coefficient both become larger without the significant change of the sliding surface location when the variation factor increases.The safety factor,which is affected by the slope height,soil density and cohesion,has similar variation trend with the stabili-ty coefficient as the variation factor changes.While taking soil deformation into account,the internal dissipation rate in the deformation zone caused by the cohesion variation is half of that occurs on the logarithmic spiral slip surface.The limit bearing capacity increases linearly as the variation factor increases when the cohesion of the slope toe remains invariant.Under the above circumstances,the stability coefficient,the safety factor and the limit bearing capacity are larger when the cohesion of the slope toe is higher than the cohesion of the slope shoulder,instead of the reverse distribution.Consequently,the lower cohesion of the toe would more easily cause the slope failure,and the reinforcement measures should focus on the lower part of the slope to keep it stable.