半挖半填工况加筋土挡墙失稳机制试验研究与上限法分析

 设计并制作半挖半填工况的绿色加筋格宾模型挡墙，通过在挡墙顶部施加分级均布荷载，测试挡墙在各级荷载作用下的变形、土压力和筋材拉应变，并进行数值模拟，探讨挡墙承载力的发展规律和失稳模式；基于塑性极限分析的上限法，建立半挖半填工况加筋土挡墙的极限承载力，安全系数和极限高度的计算方法。研究表明：在墙顶分级均布荷载作用下，半挖半填工况加筋土挡墙承载力的发展过程可分为初始压密、正常发展、屈服和破坏失稳4个阶段；挡墙墙顶竖向沉降呈三角形分布，挡墙沿填挖交界面发生滑移失稳；挡墙面墙变形、土压力和筋材拉应变分布规律受挡墙的失稳模式影响；所推导的半挖半填工况加筋土挡墙稳定性分析方法考虑台阶面筋材的作用，具有较高的精度。

TEST STUDY OF FAILURE MECHANISM OF REINFORCED EARTH RETAINING WALL IN CUT-AND-FILL CONDITION AND UPPER-BOUND METHOD ANALYSIS

A green reinforced gabion earth retaining wall model in the cut-and-fill condition was designed and made. Its deformation，earth pressure and tensile strain of reinforcements were tested by applying hierarchical uniform loads on the wall top，combined with numerical analysis，its bearing capacity development rule and failure model were analyzed. Based on upper-bound method of plastic limit analysis，the calculating formulas for ultimate bearing capacity，safety factor and limit height of reinforced earth retaining wall in the cut-and-fill condition were obtained. The results show that，under the hierarchical uniform loads，its bearing capacity development process can be divided into initial compaction，development，yield and failure stage. The distribution form of wall top vertical settlement is triangular；and sliding instability appears along the cut-and-fill interface. The distribution law of earth pressure，deformation and tensile strains of reinforcements are affected by the failure model. The provided stability analysis method has high precision which considered the effect of reinforcements on steps.