深厚覆盖层坝基潜蚀不一定导致坝基的渗透破坏。但坝基砂砾石土内部细颗粒的流失，一方面会增大土体的渗透性；另一方面可降低土体的强度和变形模量。前者导致坝基坝体渗流场的变化，从而引起坝体变形和应力变化，后者变形模量衰化，导致坝基坝体变形和应力调整。潜蚀造成的坝基和坝体应力变形对大坝的正常使用和安全性带来一定负面影响，定量评估这种影响是内部不稳定砂砾石深厚覆盖层坝基采用悬挂式防渗墙处理方案设计和该类大坝运行管理的迫切需求。提出了潜蚀对大坝应力变形影响的模拟方法，对一个典型大坝设计方案进行了计算分析，该设计方案中潜蚀造成应力变形变化的两种机制中，渗流场变化机制对坝基坝体的应力变形改变远大于模量衰化造成的影响。总体上该方案潜蚀造成的坝体变形和应力变化并未显著降低坝体的安全性。

Although suffusion in the deep sandy gravel foundation probably cannot lead to seepage failure of the dam, fine grains inside the sandy gravel are lost. It results in increasing the permeability of the soil, but decreasing its strength and deformation modulus. The former causes the change of the seepage field of the foundation dam, which further induces the changes of deformation and stress of the dam body. While the latter reduces the deformation modulus and leads to the deformation and stress adjustment of the dam foundation. Since the stress and deformation of a dam and its foundation caused by suffusion bring some negative impact on the normal use and dam safety, quantitative assessment of the impact is urgently required for both of the design and operation management of such dams built on a deep internal instability sandy gravel foundation with a suspended cutoff wall. Therefore, a simulation method was proposed to investigate the effect of suffusion within the foundation on stress and deformation of the dam. A dam design with a typical suffusion suffered foundation was calculated and analyzed. It is found that in these two schemes, the effect of seepage fields on the stress and deformation of the dam foundation is much greater than that caused by the modulus decay. In general, the safety of the dam is not significantly reduced by the deformation and stress changes of the dam caused by suffusion.