软土路基变形规律现场监测及FLAC模拟研究

In-situ monitoring and FLAC simulation of soft soil roadbed deformation law

以杭州绕城高速公路K28+830粉喷水泥搅拌桩处理试验段为工程背景,采用现场监测及FLAC2D数值模拟相结合的方法,对软土的蠕变-固结变形规律进行了研究。给出了路基变形现场监测方案,进行了软土路基变形平面FLAC2D模拟计算。结果表明,粉喷水泥搅拌桩使软土路基沉降和水平位移明显减小,地基稳定性增强,适宜加固饱和软粘土地基,尤其适合于桥头有相对硬层作为持力层的地段。FLAC2D计算结果总体上能反映实测的路基变形发展趋势,计算结果与现场监测结果基本一致。粘塑性蠕变本构模型可用于软土路基沉降预测预报,对软土路基沉降控制有一定参考价值。

Under the engineering background of experimental section K28 ＋ 830 treatmented by cement injection mixing pile method of express highway circling city in Hangzhou, based on the method combining in-situ monitoring with FLAC2D numerical simulation, creep-consolidation deformation laws of soft soil are researched. In-suit monitoring scheme of roadbed deformation is given. Moreover, FLAC^2D simulating calculation of soft soil roadbed is carried out. The results show that settlement and horizontal dis- placement of soft soil roadbed are reduced obviously by cement injection mixing pile. The stability of soft soil roadbed have been strengthened. Therefore, cement injection mixing pile is suitable for consolidating saturated soft clay roadbed, especially for the section in which relatively hard layer is served as bearing stratum in bridgehead. FLAC^2D calculation results are consistent with in-suit monitoring results, which can reflect development trend of roadbed deformation. Constitutive model of viscoplastic creep can be used to predict soft soil settlement. The model has some reference value to control soft soil settlement.