偏压作用下软土沉井施工力学响应及方案优选  

Mechanical Response and Scheme Optimization of Soft Soil Caisson Construction under Bias Pressure

作　　者：习宇 林志威 XI Yu;LIN Zhiwei(Guangzhou Municipal Engineering Design and Research Institute Co.,Ltd.Guangzhou 510060,China)

机构地区：[1]广州市市政工程设计研究总院有限公司,广州510060

出　　处：《广东土木与建筑》2025年第3期14-18,共5页Guangdong Architecture Civil Engineering

基　　金：广东省住房和城乡建设厅科技创新计划项目(2022-K4-094918)。

摘　　要：沉井邻近路基边坡施工时,要承受较大的偏压作用,探索其施工安全与结构稳定十分必要。依托典型工程实例,揭示软土偏压作用下现场实施难点,建立沉井施工全过程三维模型,探讨不同工法土层、结构力学响应特征,以此为基础综合多指标评价提出最优实施方案。结果表明:软土区偏压作用下,新建沉井存在结构安全和顶管施工偏差问题。沉井排水下沉诱发的土层、结构最大位移为不排水法的3.27倍和2.84倍,对应结构内力增大31.7%,两种方案均满足强度要求。两种方案沉井结构临坡侧出现了鼓肚状变形,位移明显大于对侧,表征出最大5.77mm(不排水法)和7.38mm(排水法)的悬臂侧移,满足施工误差要求。以施工安全和环境保护为主控因素,综合考虑工程费用、工期及实施难度等因素采用不排水施工方案。It is necessary to explore the construction safety and structural stability of the open caisson adjacent to the subgrade slope due to the large bias pressure during the construction.Based on typical engineering examples,the difficulties of field implementation under the action of soft soil bias are revealed and the three-dimensional model of the whole process of caisson construction is established.The mechanical response characteristics of soil layer and structure of different construction methods are discussed.Based on this,the optimal implementation scheme is put forward by comprehensive multi-index evaluation.The results show that under the action of bias in soft soil area,the new caisson has the problems of structural safety and pipe jacking construction deviation.The maximum displacement of soil layer and structure induced by open caisson drainage sinking is 3.27 times and 2.84 times that of undrained method,and the corresponding internal force of structure increases by 31.7%.Both schemes meet the strength requirements.There is a bulging deformation on the slope side of the caisson structure in the two schemes,and the displacement is obviously larger than that on the opposite side.The maximum cantilever lateral displacement of 5.77 mm(undrained method)and 7.38 mm(drainage method)is characterized,which meets the requirements of construction error.Based on a comprehensive comparison,it is recommended to adopt the non-dewatering method for construction.

关 键 词：沉井施工 力学响应 偏压作用 方案优选 数值模拟 

分 类 号：TU475[建筑科学—结构工程]