大面积堆载预压处理深厚软基工后沉降预测研究
Prediction of post-construction settlement of soft foundation after large-area surcharge preloading treatment
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摘要: 沉降预测问题一直是软土工程中的难点,而基于实测数据的沉降预测法最为直观有效,但传统的沉降预测方法具有可靠度和预测精度均较低等局限。提出一种新的基于现场实测数据的工后沉降预测模型,利用最小二乘法对模型参数进行求解。结合某石化基地软基处理的现场沉降监测数据,分析地表沉降规律和沉降速率,结果表明新的沉降预测模型预测的沉降曲线与实测曲线非常接近,验证了其合理性。分析表明:较传统的预测方法更为精确,尤其是中后期的预测结果;将整个软土处理沉降期进行分级叠加预测,相对应每一级模型参数也不同,更符合实际软土沉降规律;对比不同地层厚度的长期沉降预测结果,软土工后沉降量与软土厚度密切相关,软土厚度越大沉降越大。Abstract: The problem of prediction of soft soil settlement has always been a difficult problem in engineering, but the settlement prediction method based on the measured data is intuitive and effective. The traditional settlement prediction method has the limitation of low reliability and low accuracy, so a new settlement prediction model is proposed. The characteristics of the new settlement prediction model are analyzed, and the model parameters are solved by using the least square method. Based on the site settlement monitoring data of soft foundation treatment in Zhoushan Green Petrochemical Base, the surface subsidence law and settlement rate of monitoring points are analyzed, and the new settlement prediction model is verified theoretically. Finally, the following three conclusions are drawn. Using this model to predict the settlement of soft soil for a long time is more accurate than using some traditional prediction methods. The prediction of the middle and late periods of this method is relatively accurate, and the predicted results of the middle and late periods of actual engineering are more meaningful. The relative error of this method is smaller than that of the three-point method and the hyperbolic method. It is proposed that the whole settlement period of soft soil treatment should be graded and superimposed, and the corresponding parameters of each model are different, which is more in line with the law of actual soft soil settlement. The larger the thickness of soft soil, the greater the settlement.