桥隧合建中桥梁托换与支护一体化技术研究

Study on Integrated Technology of Bridge Underpinning and Support in Bridge-Tunnel Co-construction

摘要:

地下隧道工程建设过程中，与既有桥梁改造合建以其资源节约、空间集约等优势，近年来在城市地下工程建设中备受青睐。某公路新建隧道与既有跨线桥改造合建过程中，采用了扩大原有承台、新建托换桩基，同时将托换桩基兼做隧道基坑支护桩的设计方案，在保证基坑正常施工的同时确保了既有桥梁的正常使用。该方案对部分构造细节进行了创新设计，并采用有限元模型对施工全过程进行计算分析。结果表明：在托换施工过程中，围护桩水平位移、新建承台沉降值均满足变形要求；其中的关键工艺和局部构造细节对今后同类型的桥隧合建工程具有参考意义。

Abstract:

During the construction of underground tunnel projects, the co-construction with existing bridges has been favored in urban underground engineering in recent years due to its advantages such as resource conservation and space intensification. During the co-construction of a new highway tunnel and the existing overpass, the design scheme of enlarging the original bearing platform, constructing new underpinning pile foundations, and using the underpinning piles as retaining piles for the tunnel foundation pit was adopted to ensure the normal construction of the foundation pit and the normal operation of the existing bridge. Innovative designs were made for some structural details, and a finite element model was used to calculate and analyze the whole construction process. The results show that the horizontal displacement of the retaining piles and the settlement of the new bearing platform during the underpinning construction meet the deformation requirements. The key technologies and local structural details are of reference significance for similar bridge-tunnel co-construction projects in the future.