The security and stability of soil structures is seriously affected by earthquake-induced liquefaction, and many earth embankments located in seismically active areas failed to meet the new seismic design code criteria, introduced following the 2011 off the Pacific coast of Tohoku Earthquake. This paper proposes an appropriate in-situ countermeasure, and the seismic performance of the liquefaction mitigation method by grouting is numerically evaluated. The elastoplastic constitutive model of cyclic mobility (CM) model can present the cyclic shearing and liquefaction properties of cohesionless sand and cohesive clay in embankments, by considering stress-induced anisotropy, over-consolidation, and soil structure. A numerical investigation, based on the water-soil coupled finite element and finite difference (FE-FD) methods is conducted to explain the dynamic behavior of embankment in fully saturated sandy deposits, during an earthquake, and long-term post-consolidation in a consistent manner. Special emphasis is placed on the growth of excess pore water pressure (EPWP), acceleration response, and ground deformation (settlement and lateral spreading) in liquefiable soil during earthquake and post-earthquake consolidation (approximately 50 years). A comparative analysis demonstrates that the implemented countermeasure is effective in reducing co-seismic and post-seismic liquefaction-induced deformation, regardless of whether the top sandy layer on both sides of the embankment is completely liquified during the earthquake loading. However, there is local failure on the embankment slope instead of deep-seated failure in the embankment-soil system when grouting the saturated sandy layer, and appropriate countermeasures should be adopted to protect the slope. Furthermore, the ground strengthening effect is not apparent when the reinforcement thickness exceeds 6 m.

地震引起的液化会严重影响土壤结构的安全性和稳定性，地震活跃区中的许多土堤未能满足新的抗震设计规范标准，这是2011年东北太平洋地震后引入的。本文提出了一种合适的原位对策，并对注浆液化方法的抗震性能进行了数值评估。通过考虑应力引起的各向异性，超固结和土壤结构，循环迁移率（CM）模型的弹塑性本构模型可以显示路堤中无粘性砂和粘性黏土的循环剪切和液化特性。数值研究 基于水土耦合有限元和有限差分法（FE-FD），以一致的方式解释了地震过程中完全饱和砂质沉积物中路堤的动态行为以及长期后固结。在地震和地震后固结（约50年）期间，应特别注意液化土壤中过高孔隙水压力（EPWP）的增长，加速度响应和地面变形（沉降和横向扩展）。对比分析表明，无论在地震荷载作用下路堤两侧的顶部砂土层是否完全液化，所采取的对策均能有效减少同震和震后液化引起的变形。然而，注浆饱和砂土层时，路堤边坡存在局部破坏，而不是路堤-土壤系统中的深层破坏，应采取适当的对策以保护边坡。此外，当加固厚度超过6 m时，地面加固效果不明显。