论文部分内容阅读
基坑开挖卸荷过程伴随着坑底土层的回弹,可能对基坑稳定性和既有工程桩造成显著影响。现有的基坑回弹量预测方法有残余应力法和自重应力抵消法等,在此基础上提出了一种预测基坑回弹变形的新方法。该方法考虑开挖卸荷过程中超固结比与静止侧压力系数的联动变化关系,推出卸荷后各土层的初始残余应力以修正偏大的卸荷应力,并将土层的有效自重应力作为残余应力,再结合残余应力法计算回弹模量。通过5个工程实例与现有计算方法进行对比分析,表明该方法的计算结果与实测结果较匹配,用超固结比能够反映卸荷应力的变化。
The unloading process of foundation pit excavation accompanied by the rebound of the soil layer at the bottom of the pit may have a significant impact on the stability of the foundation pit and the existing engineering piles. Existing methods for predicting springback of foundation pit include residual stress method and self-weighting stress offsetting method. Based on this, a new method of predicting springback of foundation pit is proposed. In this method, the relationship between overconsolidation ratio and static pressure coefficient during excavation unloading is considered. The initial residual stress of each soil after unloading is deduced to correct the large unloading stress, and the effective self-weight stress As the residual stress, combined with the residual stress method to calculate the modulus of resilience. The comparison between the five engineering examples and the existing calculation methods shows that the calculated results of the method are in good agreement with the measured ones. The excess consolidation ratio can reflect the change of unloading stress.