Landslide dams (LDs) are usually composed of natural debris materials and normally exhibit heterogeneous strata along both the depth and run-out directions. In addition, LDs usually have weaker structures than undisturbed ground and are more vulnerable to seepage loading. Considering that the surface layer of naturally packed LD materials is mostly in an unsaturated state, it is undoubtedly important to investigate the hydraulic/mechanical behavior of LDs with heterogeneous strata subjected to seepage loading. In this paper, a systematic flume test program was firstly conducted, in which the Tangjiashan LD was carefully referenced for its model design. Three different water level rising rates and two different stratal arrangements were considered in the flume tests. Then, soil-water-air coupled finite element analyses were conducted to simulate the flume tests, and all the material parameters of the LD materials were carefully determined based on the results of element tests. A comparison of the test and calculated results showed the possibility of using the proposed numerical method to predict the occurrence of dam breaching and to estimate the risk of LD failure. Moreover, the hydraulic/mechanical behavior of the LD materials and the heterogeneous strata of the LD were proven to be very important to the stability of the LD. Finally, from an engineering viewpoint, the possibility of utilizing a naturally formed LD, and not destroying it after its formation, is also discussed.

滑坡坝（LDs）通常由天然碎屑材料组成，通常沿深度和延伸方向呈现异质地层。此外，LD 的结构通常比未受干扰的地面更脆弱，更容易受到渗流载荷的影响。考虑到自然堆积的 LD 材料的表层大多处于非饱和状态，研究具有非均质地层的 LD 在渗流荷载作用下的水力/力学行为无疑是重要的。本文首先进行了系统的水槽试验方案，其中唐家山LD的模型设计被仔细参考。在水槽测试中考虑了三种不同的水位上升率和两种不同的地层排列。然后，采用土壤-水-空气耦合有限元分析模拟水槽试验，并根据单元试验结果仔细确定LD材料的所有材料参数。测试和计算结果的比较表明，使用所提出的数值方法来预测大坝溃坝的发生和估计 LD 失效风险的可能性。此外，LD 材料的水力/机械性能和 LD 的异质层被证明对 LD 的稳定性非常重要。最后，从工程的角度，还讨论了利用自然形成的 LD 并且在其形成后不破坏它的可能性。测试和计算结果的比较表明，使用所提出的数值方法来预测大坝溃坝的发生和估计 LD 失效风险的可能性。此外，LD 材料的水力/机械性能和 LD 的异质层被证明对 LD 的稳定性非常重要。最后，从工程的角度，还讨论了利用自然形成的 LD 并且在其形成后不破坏它的可能性。测试和计算结果的比较表明，使用所提出的数值方法来预测大坝溃坝的发生和估计 LD 失效风险的可能性。此外，LD 材料的水力/机械性能和 LD 的异质层被证明对 LD 的稳定性非常重要。最后，从工程的角度，还讨论了利用自然形成的 LD 并且在其形成后不破坏它的可能性。