绿汁江大桥B4桥位玉溪岸开挖方案比选研究

B4 Abutment Site Excavation Plan for the Lvzhijiang River Crossing Bridge

桥梁及其附属建构筑物的建设不可避免地对桥址自然地形进行开挖扰动,合适的开挖加固方案显得尤为重要。以玉楚高速公路绿汁江大桥B4桥位玉溪岸边坡为研究对象,在现场调查和勘察的基础上,确定了玉溪岸桥址岸坡稳定性的主要控制因素,采用极限平衡法分析了不同开挖方案下的隧道施工平台上下边坡、索塔下边坡的工程稳定性,对各部分边坡提出安全经济的加固措施。最后依据各方案的开挖方量和加固措施费效比,推荐了小开挖方案作为玉溪岸桥址岸坡最优方案,为类似工程的开挖加固提供参考。

The excavation reinforcement is frequently required for the construction of the bridge structure and its ancillary structure such as, bridge foundations, tower foundations and anchorage blocks. Therefore, selecting the appropriate excavation and reinforcement system is particularly important. This paper presents the excavation plan for the B4 bridge abutment site at the left bank of Yuxi River. The proposed B4 bridge is for the Yu-Chu Expressway at the Lvzhijiang river crossing. Factors that affecting the stability of the bridge abutment at the left bank were evaluated through the geological survey and subsurface investigations. The stability issues of slopes below and above the proposed tunnel construction trestle and slopes below the cable stay tower were analyzed by using limit equilibrium method. The slope stability mitigation and reinforcement measures at various locations are proposed with comprehensive cost comparations. The optimized excavation plan with balanced excavation volume and cost was proposed.