中等跨度上承式拱桥深基岩拱脚基础方案研究

Research on Deep Bedrock Arch Springing Foundation Scheme of Medium-span Deck Arch Bridge

摘要:

山区地形起伏大，深谷、水道较多，常采用上承式或中承式等跨越性能好的有推力拱桥方案。但不同地区地质多样，常有不良地层构造，给有推力拱脚基础的建设带来很大困难。基于深圳市某公园中一座深基础的中等跨度上承式拱桥项目，分析了常见有推力拱脚类型的适用性特点，提出了5种拱脚基础结构设计方案，并采用数值分析方法对比不同方案在山地、河滩2种地质条件下的受力及变形情况。分析结果表明：在深基岩地区采用大直径斜桩、扩大基础、地下连续墙等基础结构将具有更好的承载性能，但普通带有斜桩的群桩基础方案经济性最好，且便于施工，更适用于水平力不大的拱桥基础结构中；此外，普通群桩基础受力对地层特性比较敏感，应重点关注该类问题。

Abstract:

The terrain in mountainous areas is highly undulating with many deep valleys and waterways, where the thrust arch bridge schemes with good span, such as deck or half-through types, are often adopted. However, the geology in different regions is diverse, and there are often poor stratum structures, which will bring the great difficulties to the construction of thrust arch springing foundation. Based on a medium-span deck arch bridge with a deep foundation in a park of Shenzhen, the applicability characteristics of common thrust arch springing type are analyzed, five foundation structure design schemes of arch springing are proposed, and the numerical analysis method is used to compare the stress and deformation of different schemes under two geological conditions of mountainous area and river beach. The analysis results show that the foundation structures of large-diameter inclined pile, enlarged foundation and underground diaphragm wall adopted in the deep bedrock area will have the better bearing performance, but the common pile group foundation scheme with inclined piles has the best economy and is convenient for construction, which is more suitable for the arch bridge foundation structure with little horizontal force. In addition, the force of common pile group foundation is more sensitive to the formation characteristics, which should be paid more attention.