关键词: 地震液化, 土石坝, 土层置换, 材料参数, 优化分析

Abstract: Seismic liquefaction of earth-rock dams may cause structural instability, foundation failure or other problems, severely threatening the safety of dam projects. New anti-liquefaction measures of soil removal and replacement should be designed, as the previous design of soil replacement schemes was usually based on engineering experiences, lacking quantitative optimization analysis of the soil replacement materials (SRMs). This paper presents an optimization analysis method of the key SRM parameters, considering the liquefaction of earth-rock dam foundation under earthquake action. Based on real project data, numerical simulations and optimization analysis of SRMs are carried out, revealing variations in seismic liquefaction under the influence of the four groups of SRM parameters, i.e., porosity, density, bulk modulus and shear modulus, as well as cohesion and internal friction angle. We find that in the common range of soil parameters, the anti-liquefaction effect is poor for a scheme using too small or too large porosity and density, while it is better for a scheme using a large modulus and a large internal friction angle. The key SRM parameters can be optimized through a procedure of comparison, selection, and optimization of the schemes. This can achieve a significant improvement in the vertical displacement of a dam body, as shown in our case study: an optimization rate of 53.9% for the downstream dam slope ratio, and 69.6% for the residual liquefaction volume at the end of dynamic analysis. This demonstrates our method is effective and applicable to optimization analysis of earth-rock dam replacement materials, along with its great significance for improving anti-liquefaction performance of earth-rock dams.

Key words: seismic liquefaction, earth-rock dam, soil replacement, material parameter, optimization analysis