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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。
Deep covering layer dam base erosion does not necessarily lead to infiltration of dam foundation damage. However, the loss of fine particles inside the gravel soil in the dam foundation will increase the permeability of the soil on the one hand and reduce the strength and deformation modulus of the soil on the other hand. The former results in the change of the seepage field in the dam foundation, which leads to the deformation and stress changes of the dam. The deformation modulus of the latter declines, resulting in the deformation and stress adjustment of the dam foundation. The potential deformation and deformation of the dam foundation and the dam caused by the erosion have a certain negative impact on the normal use and safety of the dam. The quantitative assessment of this effect is due to the instability inside the sand-gravel deep overburden dam foundation using hanging-type cut-off wall treatment scheme design and The urgent need of such dam operation and management. The simulation method of the influence of the erosion on the stress and deformation of the dam is put forward. The design scheme of a typical dam is calculated and analyzed. Among the two mechanisms of the potential dam deformation caused by the latent erosion, the mechanism of the variation of the seepage field affects the dam foundation The change of stress and deformation is far greater than the effect of modulus degradation. On the whole, the deformation and stress change of the dam caused by this scheme did not significantly reduce the safety of the dam body.