新建铁路路基形式对既有公路桥梁桩基的影响分析

以西南地区某新建铁路下穿既有高速公路桥梁为例，基于有限元软件，对旋喷桩复合地基路基和锚固桩+旋喷桩复合地基路基下穿既有高速公路方案的可行性进行综合评价。结果表明：采用旋喷桩复合地基对软土进行加固处理，形成了较好的竖向加固体，增强了被加固土体的力学特性，减小了新建铁路对桥梁桩基的影响；在软土地区两侧设置锚固桩的方式，约束了地基土的侧向变形，对限制工后沉降具有较好的效果。

Analysis of Influence of New Railway Subgrade Types on Existing Highway Bridge Pile Foundation

Taking a new railway underpassing an existing expressway bridge in southwest China as an example, based on the finite element software, the feasibility of highway schemes of rotary jet grouting pile composite foundation subgrade and anchored pile + rotary jet grouting pile composite foundation subgrade underpassing the existing expressway is comprehensively evaluated. The result shows that the soft soil was reinforced with the rotary jet grouting pile composite foundation, which formed a better vertical reinforcement, enhanced the mechanical properties of the reinforced soil, and reduced the impact of the new railway on the bridge pile foundation. The way of setting up anchoring piles on both sides of the soft soil area restrains the lateral deformation of the foundation soil and has a good effect on limiting post-construction settlement.