Abstract: Taking cutting landslide of expansive soils controlled by discontinuities as an example, a simple mechanical model considering water swelling is proposed, which takes the strain-softening and water-softening of slip surface materials under the condition of rainfall into the consideration. Furthermore, the mechanism of the cutting slope of expansive soils is analyzed by catastrophe theory. Many factors trigger landslide, such as moisture content and stiffness ratio. The results show that evolution process of landslide is resulted from internal and external factors, and the cause of rainfall resulting in softening-swelling of discontinuities belongs to the external triggering factors. The water controlling should be taken into consideration in the process of reinforcing cutting slope.

Key words: cusp catastrophe , strain-softening , water-softening , stiffness ratio , flexible retaining structure ;

摘要： 以受结构面的控制膨胀土堑坡滑坡失稳为例,考虑降雨条件下,滑面介质的应变软化和水致弱化,提出了一 个简单的考虑吸水膨胀的力学模型,并利用突变理论分析其失稳破坏的力学机制。在突变分析中,通过尖点突变 模型,分析了刚度比、含水量等因素对滑坡的触发作用。结果表明:滑坡的演化过程是内外部因素共同作用的结 果,降雨导致结构面介质膨胀软化的原因属于外部的触发因素。在膨胀土堑坡的加固防护中,应当充分地考虑水 的治理。

关键词: 尖点突变, 应变软化, 水致弱化, 刚度比, 柔性支挡结构