气泡混合轻质土置换高速公路路堤工后沉降研究

Research on Post-construction Settlement by Using FCB to Replace Expressway Embankment

以申嘉湖杭高速公路(练杭段)堆载预压处理段路基沉降速率较大断面采用气泡混合轻质土置换高速公路路堤为例,采用土体弹塑性本构模型及Bjerrum等时e-lgp曲线理论,对置换后地基土体的应力路径变化进行理论分析,地基土处于超固结状态;通过现场实测沉降资料,置换前处理段沉降观测点月沉降量在14 mm^18 mm,置换后沉降观测点月沉降量在2 mm^4 mm,沉降速率收敛较快,处理后效果明显,能够有效减少工后沉降。结果表明,采用气泡混合轻质土置换高速公路路堤不仅施工方便,质量容易控制,而且处理效果显著,是一种有效的减少软土地基工后沉降的控制方法。

Through the application practice for the embankment replacement by using FCB in the cross section with larger roadbed subsidence rate of the surcharge preloading reach in Shen-Jia-Hu-Hang Expressway （Lian-Hang reach）, and based on the soil＇s elastoplastic constitutive model and Bierrum e - lgp curve theory, the theory analysis is carried out here according to the soil stress paths after replacement, and it is known that the foundation soil is in overconsolidated state; Simultaneously, it is known through the field-measured settlement data analysis that the monthly settlement of the settlement observation points in the processing reach before replacement is in 14 mm- 18 ram, the monthly settlement af- ter replacement is in 2 mm- 4 ram, the settlement rate convergence is rapid, and the effect after treatment is obvious, so the post-construction settlement could be reduced effectively. The results show that using FCB to replace the expressway embankment is not only convenient in construction and easy for quality control, but also obvious in treatmeat effect, so it is a kind of effective control method for reducing the post-construction settlement.