The effect of soft substratum on the stability of soil-nailing walls is discussed through analysis of project cases. The deformation characteristics of soil-nailing walls in soft soil area are revealed. Some measures are proposed to control the deformation. Besides, field tests are carried out through pulling out soil nails in soft soil area with high speed and low speed respectively. The test results are compared and the characteristics of the resisting force when pulling out the nails from soft soil are analyzed. Based on the test results, a quick pullout capacity test method is proposed. Some suggestions are put forward for the design of the length and space of soil-nails in soft soil area; and some opinions are proposed about the current soil-nailing retaining structure design code.%通过工程实例计算分析软弱下卧层对土钉支护稳定性的影响,揭示软土中土钉墙的变形特点,并提出控制位移的措施.介绍在软土地区进行的土钉原位快拔和慢拔试验,通过对2种试验结果的对比,分析软弱土层中土钉抗拔承载力的特征,提出通过快拔试验对土钉的抗拔承载力进行测试的方法;同时,提出软土地区有关土钉长度和间距设计的建议以及对现行规范中有关土钉支护结构设计的补充意见.
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