某多层结构堤基土体渗透变形机理模拟研究

Numerical Study on Seepage Deformation Mechanism of Multi-layer Embankment Foundation

针对某多层结构堤基渗透稳定性问题,采用基于离散元理论的颗粒流方法,建立堤基概化颗粒模型并进行渗流模拟,研究多层结构堤基渗透变形发展过程及颗粒流失量、孔隙率等参数的变化规律。结果表明,对于上覆粘土,下部为级配不良中砂和级配不良细砾的土层结构,发生渗透破坏时土体颗粒流失主要发生在中砂层,渗漏通道表现为由渗流出口逐渐向上游发展,由于流失量持续增大,造成该土层逐渐被掏空并导致上覆粘土层塌陷破坏;细砾石层颗粒流失量较小且趋于稳定,不会演变为管涌破坏。

To study the seepage stability of multi-layer embankment foundation, the particle model of embankment foundation was established by using the particle flow method based discrete element theory. The variation of particle loss and porosity of the model during the process of multi-layer embankment seepage deformation have been studied. The nu merical results show that for the soil structure of upper layer clay, the lower layer with bad medium sand and bad fine gravel, the soil erosion mainly occurs in the medium sand layer when seepage failure occurs. The seepage channel devel- ops gradually from the seepage outlet to the upstream. Because of the constant increase of the amount of particle loss, the soil erosion occurred and the overlying soil layer was collapsed. The fine particles loss is small and tends to be stable, and will not develop into the piping failure.