静力作用下夯土遗址根部掏蚀失稳机制实验研究

Experimental Study on Instability Mechanism of Rammed Earthen Ruins Caused by Basal Sapping under Static Action

摘要:

根部掏蚀是土遗址坍塌的主要因素。关于土遗址掏蚀失稳机理已有众多研究成果，但主要基于数值模拟和理论分析，等比例进行根部掏蚀实验的研究较少。基于夯土遗址掏蚀调查研究，制作1∶1夯土墙体模型，通过墙体根部掏蚀实验和数值模拟对其失稳机制进行研究。实验结果表明：掏蚀深度小于20%时，墙体应力变化很小；掏蚀深度大于20%时，墙体出现偏应力，并且快速增大；掏蚀深度为45%时，墙体发生倾倒破坏。在实验过程中，墙体应力重分布主要发生在掏蚀阶段，掏蚀稳定后应力变化不明显；墙体倾倒破坏过程非常迅速，整体表现为刚性倾倒，从夯层根部层界面拉裂是主要破坏模式，其应力应变特征与数值模拟结果相吻合。研究成果可为夯土遗址根部保护和夯筑支顶加固提供参考依据。

Abstract:

Basal sapping is the main factor of soil site collapse.Numerous research results on the sapping instability mechanism of earthen sites are mainly based on numerical simulation and theoretical analysis,and the researches on experiments of basal sapping with equal proportions are few.Based on the sapping investigation and research of rammed earth site, a 1∶1 rammed wall model was established in this paper,and the instability mechanism was studied by means of experiment and numerical simulation of wall basal sapping. The experimental results showed that:when the sapping depth is less than 20%,the wall stress changes little;when the sapping depth is more than 20%,the deviatoric stress appears and increases rapidly;when the sapping depth reaches 45%,the wall collapses.During the experiment,the stress redistribution on the wall mainly occurs in the sapping stage,and the stress change is not obvious after the sapping is stable.The collapse and failure process of the wall is very rapid,and the whole performance is rigid dumping.The stress-strain characteristics are consistent with the numerical simulation results.The research results can provide a reference for the basal protection of rammed earth sites.