[提要]  以试验为基础，探讨了软土地区基坑开挖坑底被动区土体处于卸荷状态时，其强度变化的特征及范围，结果对分析基坑稳定、变形及确定坑底被动区土体加固范围等具有参考价值。
[关键词]  软土地区  卸荷状态  强度变化  试验研究

Through experiments, the change, characteristic and range of the soil strength are discussed, when the soil of passive area is unloading in the soft-clay area.During excavation of foundation pits, the results have some help to analyse stability and deformation in the pits and determine the range of stabilizing grout soil of the passive areas in soft-clay.
Keywords:  soft-clay area; soil in unloading; strength change; examination study