路桥过渡段软土地基加固沉降对比分析

为比较抗滑桩与CFG桩的加固效果，以某高速公路软土地基路桥过渡段为例，基于FLAC3D模拟计算抗滑桩和CFG桩加固路基填筑后Z方向的地表沉降。台背后20 m范围内的计算结果为：(1)抗滑桩只对其周围土体有加固挤密作用，对距桩体1 m以外的加固作用较弱，分别发生0.62～13.28 cm的沉降；(2)CFG桩加固方案中，桩心距为1.8 m区域的沉降量在2.5 cm以内，桩心距为3.6 m区域沉降量在4 cm以内，在加固区域地基中没有出现土体破坏和生滑动现象，因此采用CFG桩为该桥台的加固方案。对完工的CFG桩进行单桩竖向抗压静载试验与沉降监测，测得台后20 m处桩顶总沉降值为3.89 cm,与数值模拟结果吻合，说明CFG桩可有效减少地基塑性区域、提高地基承载力和降低沉降量。

Comparative Analysis of Settlement for Soft Soil Foundation Reinforcement in the Road and Bridge Transition Section

In order to compare the reinforcement effects of anti-slide piles and CFG piles, taking an expressway soft soil foundation of road and bridge transition as an example, the surface settlement in Z direction after anti-slide piles and CFG piles are simulated and calculated based on FLAC3D software. The calculation result within 20 m behind the stage is: (1) the anti-slide pile only has a strengthening and compaction effect on part of the soil around the pile, and has a very weak strengthening effect on the soil more than 1m away from the pile, the vertical displacement is respectively 0.62~13.28 cm at different distances. In the CFG pile reinforcement scheme, the settlement of the area of pile center spacing with a distance of 1.8 m and 3.6 m is respectively within 2.5 cm and 4 cm, there is no soil failure and sliding failure in the foundation of the reinforcement area. Therefore, CFG pile is adopted as the reinforcement scheme in this project. The actual CFG pile was tested for a single pile vertical static load and settlement monitored, the total settlement value of the pile top was 3.89 cm at a distance of 20 m from the abutment, which was anastomosed with the numerical simulation results. The results show that the CFG pile can effectively reduce the plastic zone of the foundation soil, improve the bearing capacity of the foundation and reduce the settlement.