摘要
在新建地铁车站零距离下穿既有地铁区间隧道施工过程中,基坑的增层开挖导致既有桩基侧摩阻力下降,从而对桩基的承载力产生不利影响。目前,新建地铁车站增层开挖施工作用下既有桩基侧摩阻力的计算理论尚不成熟。以深圳地铁13号线公明广场站零距离下穿既有6号线项目为背景,采用Mindlin应力解推导增层开挖卸荷作用下既有桩基桩侧摩阻力的计算公式,研究新建地铁车站增层开挖过程中既有桩基侧摩阻力的变化规律。通过与数值模拟结果进行对比,验证理论计算方法的正确性,在此基础上获得参数变化对桩侧摩阻力和卸荷应力的影响规律。结果表明:既有桩侧摩阻力随增层开挖深度的增大而减小,侧壁卸荷应力与总卸荷应力的比值随增层开挖深度的增加而增大;桩侧摩阻力随增层开挖面积的增大而增大,侧壁卸荷应力与总卸荷应力的比值随增层开挖面积的增大而减小。在开挖深度较深、开挖面积较小或考虑边桩侧摩阻力时,需考虑侧壁卸荷应力的影响。
During the construction of a new subway station beneath an existing operational tunnel,the shaft resistance of existing piles induced by excavation may decrease,and thus affect the bearing capacity of the piles.Currently,the theory of computing the shaft resistance for existing piles induced by excavation is not clear.Taking Shenzhen Metro Line 13 Gongming Square Station crossing the existing Line 6 project at zero distance as a case study,a calculation formula of pile shaft resistance induced by excavation under existing buildings is obtained by using the Mindlin stress solution.By comparison with the numerical simulation results,the correctness of the Mindlin stress solution is proved.The influence of parameter changes on pile shaft resistance and unloading stress is analyzed.The results show that:when the depth of excavation increases,the total pile shaft resistance decreases,and the ratio of sidewall unloading stress to total unloading stress increases;when the excavation area increases,the total pile shaft resistance increases,and the ratio of sidewall unloading stress to total unloading stress decreases.Therefore,when the excavation depth is large,the excavation area is small,or the shaft resistance of side piles is taken into consideration,the influence of the sidewall unloading stress must be taken into account.
作者
袁传旭
甄雪东
陈坤
黄阜
肖健
凌同华
YUAN Chuanxu;ZHEN Xuedong;CHEN Kun;HUANG Fu;XIAO Jian;LING Tonghua(Shenzhen Metro Construction Group Co.,Ltd.,Shenzhen 518026,Guangdong,P.R.China;China Construction Fifth Division South China Company,Shenzhen 518002,Guangdong,P.R.China;School of Civil and Environmental Engineering,Changsha University of Science and Technology,Changsha 410114,P.R.China)
出处
《土木与环境工程学报(中英文)》
北大核心
2026年第2期140-149,共10页
Journal of Civil and Environmental Engineering
基金
国家自然科学基金(52278395、52078061)。
