复杂条件下膨胀土边坡渗流和稳定性分析

The Analysis of Seepage and Stability for Expansive Soils Slope under Complicated Environments

膨胀土的工程性质受周围环境及气候的影响比较大，很多膨胀土边坡的失稳破坏是在降雨时或者降雨后发生的。对膨胀土边坡失稳而言，胀缩性和裂隙性是内在因素，降雨入渗是外部诱发条件。用SEEP／W和SLOPE／W软件对膨胀土渠坡工作期间水位快速升降、降雨入渗以及自然蒸发等可能工况进行了系统分析，并考虑了裂隙的影响。分析结果表明，由于非饱和土的渗透系数很小，渠坡内部各种物理场要经过较长的时间才能达到稳定；水位快速升降对临水面含水量和压力水头的影响较快，需要经过一定时间才能影响渠坡内部的含水量和压力水头变化；膨胀土张裂缝对降雨入渗有显著的影响，含水量和总水头影响范围达到张裂缝底部；水位快速下降会导致边坡安全系数降低。研究结果对边坡稳定性分析很有意义。

The engineering character of expansive soils is influenced by circumstance and climate around. Large amounts of failure in slope happen at or after rainfall. Swelling or shrinking character is internal factor of slope failure, rainfall is external reason. This paper proposes numerical analysis of expansive soil slope taken into account of infiltration ,evaporation and fissure of soil. According the results,the steady states for various fidds such as pore water pressure,water content,etc. ,inside a slope need a long time for low hydraulic conductivity of expansive soil. The fast variation in water level can influence the water content and hydraulic head in space near water rapidly. Tension crack evidently influence infiltration. Results show the safety factor decreasing largely when water level decreasing suddenly. The results has guide significance on engineering.