基于CPTU测试的高速公路拓宽复合地基沉降计算研究

Settlements of composite foundation for expressway expansion based on CPTU tests

复合地基是软土路基处理的常用方法,准确计算复合地基沉降对新老路差异沉降控制具有重要意义。依托淮安至江都高速公路拓宽工程,对新老路地基进行CPTU测试和旁压试验,根据旁压试验测试得出土体的切线模型;对拓宽路基进行沉降监测,通过路基沉降反算出路基土层压缩模量,研究了CPTU测试参数计算复合地基沉降的计算模型,并与传统的经验关系模型进行对比分析。结果表明:提出的复合地基沉降计算模型能准确计算路基的沉降,计算结果与实测沉降接近,提出的计算模型明显优于传统经验关系模型。在复合地基沉降计算中建议使用本文提出的计算模型。

The composite foundation is a common method for treatment of soft soil subgrade.The accurate calculation of settlements of composite foundation is of great significance for differential settlement control of new and old roads.Based on the widening project of Huai'an-Jiangdu Expressway,the CPTU tests and pressuremeter tests on the foundation of the new and old roads are conducted,and the tangent model for the soil is obtained according to the pressuremeter tests.The settlements of the reconstructed and expanded subgrade are monitored,and the compression modulus of the subgrade soil layer is back-calculated through the settlements of subgrade.The model for calculating the settlements of the composite foundation using the parameters of the CPTU tests is studied and compared with the traditional empirical relationship model.The results show that the proposed model can accurately calculate the settlements of subgrade,and the calculated results are close to the measured settlements.The proposed model is obviously superior to the traditional empirical relationship model,and it is recommended to use in the settlement calculation of composite foundation.