Logistic模型在基坑沉降预测的应用研究

Application Study on Settlement Prediction of Foundation Pit with the Logistic Model

基坑开挖全过程的地表沉降量可用Logistic生长模型来描述。考虑到模型适用范围和预测精度等问题,结合工程实例,比较了模型中参数K的三种估计方法,并用线性回归获得另外两个参数a、r,应用结果表明:三种方法拟合精度都较高,其中以三点法最优;在沉降发展的时间预测上,根据模型的数学意义,以拐点法最优,三点法和四点法预测效果不理想。

The settlement-time relationship of foundation pit during the whole process of excavation can be described by Logistic model. Considering the range of applicability and prediction accuracy of the model, three estimation methods for parameter K of the model are compared based on the practical engineering and the other two coefficients a, r are got by the linear regression method. The results indicated that three methods all make good fitting precision, especially the 3-point method; according to the mathematical meaning of the model, the yielding point method gives more rational evaluation in the case of settlement trend prediction than the 3-point method and the 4-point,