摘要
珠海横琴二桥跨天沐河段桥型为2联3X50m预应力钢筋混凝土宽幅连续箱梁桥，该桥94号.97号墩承台地处深厚软弱地质条件，为确保钢板桩围堰支护结构的稳定及安全性，综合考虑承台结构尺寸、承台埋深、地质及水文条件后，确定采用复合地基处理与钢板桩围堰相结合的方案。钢板桩围堰平面尺寸为12.2mX11m，拉森F型Q345B钢板桩长18m，围堰内设2道内支撑。封底混凝土面下淤泥层采用9m长水泥搅拌桩加固成复合地基。采用等值梁法对钢板桩围堰进行力学计算，并采用MIDASCml有限元软件建立最不利工况梁单元模型，采用容许应力法对钢板桩强度、内支撑、基坑底土抗隆起进行验算，结果均满足规范要求。
T he Second H engqin Bridge in Zhuhai is a wide prestressed reinforced concrete continuousbox girder bridge,w ith tw o continuous units of3X50m.T he pile caps for pier No.94:?97are located in the region w ith poor geological condition.To ensure the stability and safety of thesupporting structure of the steel sheet pile cofferdam,a schem e of com bined use of com posite foundationprocessing and steel sheet pile cofferdam w as chosen,based on the com prehensive investigationof the structural dim ensions of the pile caps,burying depth of pile caps and geological andhydrological conditions.T he plan dim ension of the steel sheet pile cofferdam m easures12.2m X llm,and the steel sheet piles m ade of Larson]V type Q345B are18m lon g,and tw o inner supportsare installed inside the cofferdam.T he sludge layer beneath the sealing concrete was strengthenedto be com posite foundation by the9m long cem ent m ixing piles.T he equivalent beam m ethod wasused to calculate the mechanical behavior of the steel sheet pile cofferdam.T he M IDAS Civil software w as used to establish the beam elem ent model of the bridge in the context of the m ost unfavorableload cases,and the allow able stress m ethod w as used to do checking calculations of thestrengths of the steel sheet p iles,inner supports and the uplifting resistance of the foundation pitsubsoil.T he results of the calculation m eet the code requirem ents.
作者
夏颂军
XIA Song-jun(CCCC Fourth Highway Engineering Co.,Ltd., Beijing 100022,China)
出处
《世界桥梁》
北大核心
2016年第6期17-22,共6页
World Bridges
关键词
软弱地质
承台
基坑支护
钢板桩围堰
复合地基
地层参数
土压力
内支撑
weak geological condition
pile cap
foundation pit su pp o rting
steel sheet pile cofferdam
com posite foundation
stratum param eter
soil p ressu re
inner support
