对工后沉降法确定卸载时机的研究

针对经常将剩余沉降用于卸载时机确定的现象,在分析剩余沉降与工后沉降区别的基础上,提出两者之间的换算公式。工后沉降法中最终沉降应是设计荷载——等载预压下所对应的最终沉降,对于超载预压、欠载预压,应根据监测资料确定沉降与填土高度的关系,从而根据超载预压、欠载预压监测资料推算得到等载预压对应的最终沉降量。对多土层地基,目前预测工后沉降的方法易导致提前卸载和实际工后沉降偏大,因此应分层确定工后沉降,然后累加得到总的工后沉降。

STUDY ON DETERMINATION OF UNLOADING TIME USING METHOD OF SETTLEMENT AFTER CONSTRUCTION

Method of settlement after construction is often used to decide unloading time.To avoid the confusion that residual settlement is regarded as settlement after construction,two equations between the residual settlement and settlement after construction are given based on the analysis of their difference.The final settlement in the method of settlement after construction is corresponding to the design load.For surcharge and undercharge conditions,the equation between final settlement and filling height should be achieved through monitoring results.The final settlement responding to the design load should be got with the above equation.For multi-layer ground,the presented method often leads to early unloading and over settlement after construction.For this kind of ground,the settlement after construction of each layer should be analyzed;and the total settlement after construction can be achieved by superimposing the settlement after construction of each layer.