引江济淮膨胀土边坡强度特性和稳定性研究

膨胀土边坡常常发生失稳破坏，其强度和稳定特性一直是膨胀土研究领域的重要课题。以引江济淮试验段工程为研究背景，通过室内往复干湿循环试验，开展膨胀土强度特性研究，探索膨胀土边坡失稳原因，并利用Geo-Studio仿真软件进行算例验证。在上述研究的基础上，继续进行膨胀土边坡防裂隙加固法的有效性验证。研究结果表明，膨胀土的抗剪强度（内聚力、内摩擦角）随着干湿循环次数的增加而逐渐减小。内聚力c的衰减主要发生在第1～2次干湿循环过程中，随后c值逐渐趋于稳定。内摩擦角φ受干湿循环的影响没有明显规律性，其衰减幅度要小于内聚力c；随着干湿循环的进行，土体裂隙不断开展，而裂隙开展才是膨胀土强度降低继而引起边坡失稳的重要原因；通过对换土及土工膜覆盖2种加固工法的算例验证，表明防裂隙法能对膨胀土边坡的加固起到良好作用。

Study on strength and stability characteristics of expansive soil slope based on the project "the Yangtze River-to-Huaihe River water diversion"

Expansive soil slopes are often destabilized，and their strength and stability characteristics has been an important topic in the field of expansive soil research.Based on a study of the project "the Yangtse River-to-Huaihe River water diversion"，the authors studied the strength and instability of expansive soil slope by laboratory wet and dry cycle test，the cause of instability of expansive soil slope was explored，and the example is verified by Geo-Studio simulation software.On the basis of the above research，the validity verification of the anti-fissure reinforcement method of expansive soil slope was carried out.The results showed that the shear strength of expansive soil decreases with the increase in the number of dry and wet cycles.The decline c in the cohesion mainly occurs in the first and second dry and wet cycles，after which the value of cohesion c tends to stabilize.The effect of wet and dry cycle on the internal friction angle φ is not obvious，its decline is less than the cohesion c.With the development of dry and wet cycles，the cracks in the soil develop continuously，and the development of fractures is the important reason for the strength reduction of the expansive soil and the instability of the slopes.Two examples were verified by soil reinforcement and geomembrane coverage，and the results indicate that the anti-fissure method can play a good role in the reinforcement of the expansive soil slope.