中等压缩性土地基工后沉降预测三参数幂函数模型

Three-parameter power function model for prediction of post-construction settlement of medium compressive soil foundation

基于最终沉降量、沉降半衰期及半衰期沉降速率表征的沉降-时间关系曲线的特征方程,分析了传统两参数双曲线和指数曲线模型存在的缺陷,构建了一个三参数的幂函数型沉降预测模型;结合蒙华重载铁路某段粉质黏土地基沉降观测数据,以均方差、关联度和偏离度为检验指标,开展了中等压缩性土地基工后沉降预测模型的准确性评价.研究表明:三参数幂函数模型较传统两参数模型能适应更多样化的沉降-时间曲线形态,在表征沉降预测有效性的检验指标方面表现更佳;以满足规范要求的工后256 d观测数据预测地基528 d沉降,三参数幂函数模型的平均偏离度仅为5.99%,而传统两参数模型分别14.38%和22.46%.本研究提供了一种新的地基工后沉降预测方法,具有一定的工程应用价值.

The characteristic equation representing the settlement-time relationship was built based on final settlement valve, half-life time settlement and half-life time settlement rate. The mathematical deficiencies of the traditional two-parameter hyperbolic model and exponential model are revealed, and a three-parameter power function model for post-construction settlement prediction is established. Using the observation settlement data of silty clay foundation in a section of Menghua heavy-haul railway, mean square error, correlation and deviation are employed as the detection indicators to evaluate the accuracy of the predicting model for post-construction settlement of medium compressive soil foundation.According to the results, compared with the traditional models, the three-parameter power function model can adapt to more settlement-time curve shapes and show more ideal test indicators. The settlement data within 256 days after construction is used to predict the settlement value on 528 days,which meets the requirements of the specification for observation time. Average deviation of the three-parameter model reaches only 5.99%, while that of the traditional models are 14.38% and 22.46%, respectively.The research provides a new predict method for post-construction settlement of soil foundation,which bears engineering application value.