软土地基桥梁下部结构纠偏措施应用与研究

Application and Study on Rectification Measures for Bridge Substructure on Soft Soil Foundation

某项目设置跨河桥梁两座,桥梁在架梁前,位于河两侧坡底的桥墩盖梁出现较大偏移,分析为软土地基扰动液化,墩柱受侧向土压力挤压变形导致。经现场质量鉴定,偏移后桥梁下部结构质量完好,可通过技术措施纠偏后继续使用。为此,该项目先后采用了挖土卸载、施打高压旋喷桩及立柱顶端牵引配袖阀管注浆3种纠偏措施进行纠偏,其中,卸土纠偏和立柱顶端牵引配袖阀管注浆纠偏效果明显,最终,桥梁下部结构纠偏成功,偏移满足规范要求。

The project consists of two river-span bridges. Before installing the beams, it found that the piers, which are located within the bottom of the river, appeared deviation to a large extent, the main reason for this is soil-liquefaction that is caused by disturbance during the piers construction, and this soil-liquefaction produces lateral force that push the pier columns incline to a certain angle. The on-site quality appraisal shows that the substructure of the bridge is intact, and that the pier columns can be used continuously after correction through technical measures. To this end, the project adopted excavation unloading, high-pressure rotary injection pile and column tip traction sleeve valve pipe grouting to correct the deviation, among which, the results of soil removal correction and column tip traction sleeve valve pipe grouting method are obvious. Finally, the incline of substructure of the bridge has been successfully corrected, and the deviation meets the standard requirements.