下伏软弱夹层路基堆载对桩基影响及处治方法

依托马里河II桥实体工程,采用现场监测和数值模拟方法,研究了高填路基邻近桥梁桩基受力及变位规律,分析了主动削方减载和增设抗滑桩前后该桥1号和3号桥墩桩基础受力特性,提出了相应的工程处治方法。研究结果表明:在台背路基堆载填土作用下,软弱夹层侧向挤压作用对邻近桥梁的墩顶位移、桩身位移、桩周土抗力均有显著影响;卸载后1号墩的墩顶位移减少94.90%~95.09%,桩顶位移减少94.74%~94.66%,桩周最大土抗力减少86.89%~94.88%;设置抗滑桩后3号墩的墩顶位移减少75.05%~80.04%,桩顶位移减少71.75%~81.38%,桩周最大土抗力减少39.99%~40.03%;台背填方对中间桩的影响较小,对边侧桩的影响较大,设计时可适当提高边侧桩的承载性能。

Effect of Road Embankment Overburden with Weak Interlayeron Bridge Pile Foundation and It's Treatment Methods

Based on the project Mali River II Bridge, the stress and displacement law of the pile foundation of bridge adjacent to high fill roadbed were studied by field monitoring and numerical simulation method. The mechanical characteristics of pier 1 and pier 3 of the bridge with the active cutting to reduce load and adding anti-slide pile were analyzed, and the corresponding treatment methods were put forward. The results show that the lateral compression of the weak interlayer has a significant effect on the pier top displacement, pile displacement and soil resistance of the adjacent bridge under the action of the backfill of the subgrade. After unloading, the top displacement of pier 1 reduces by 94.90%~95.09%, and the displacement of pile top reduces by 94.74%~94.66%, and the maximum soil resistance of pile side reduces by 86.89%~94.88%. After the anti-slide pile is installed, the top displacement of pier 3 reduces by 75.05%~80.04%, the displacement of pile top reduces by 71.75%~81.38%, and the maximum soil resistance around the pile reduces by 39.99%~40.03%. The influence of abutment backfill on the middle pile is small, and that on the side pile is large. The bearing capacity of side piles can be improved properly during design.