新型双排连续墙围堰结构开发及二线船闸应用

The Development of a New Type of Double Row Continuous Wall Cofferdam and Application of the Second Line Ship Lock

船闸改扩建面临有限空间施工和保通难题,需要综合考虑围护功能与船闸功能转化、安全性与经济性的平衡问题。依托二线船闸工程,凝练改扩建面临的共性工程问题,开发了一种新型双排连续墙加刚性连接承台和直立式前后立墙围堰结构体系,并应用于濛里水利枢纽二线船闸工程。所得结论如下:①开发了新型双排连续墙加刚性连接承台和直立式前后立墙围堰结构体系,提出了结构体系的计算力学模型,有效解决了狭窄地形条件下基坑支挡、围堰结构和导航墙三重功能相结合的问题。②与传统围护结构相比,该结构体系可有效降低基坑深度、连续墙结构悬臂段长度、坑底连续墙的嵌固深度和其结构内力,优化连续墙厚度;刚性连接承台上部回填轻质透水材料,围堰前后立墙设置排水孔,有效减小了围堰前后立墙厚度和配筋率;结合连续墙和围堰的施工工序,避免了大方量的土方回填与开挖,降低工程造价。新型围堰结构的开发有利于解决船闸改扩建面临的有限空间施工难题,为类似工程提供借鉴。

The reconstruction and expansion of the ship lock is faced with the problems of limited space construction and security.It is necessary to comprehensively consider the balance between the enclosure function and the transformation of the ship lock function,safety and economy.By relying on the second line ship lock project,this paper summarizes the common engineering problems faced by reconstruction and expansion.A new type of double row continuous wall with rigid connection cushion cap and vertical front and rear vertical wall cofferdam structure system is developed and applied to the second line ship lock project of Mengli Water Control Project.The conclusions are as follows:①A new structural system of double row continuous wall with rigid connection cushion cap and vertical front and rear vertical wall cofferdam is developed,and a computational mechanical model of the structural system is proposed,which effectively solves the problem of combining the triple functions of foundation pit retaining,cofferdam structure and navigation wall under narrow terrain conditions.②Compared with the traditional retaining structure,the structure system can effectively reduce the depth of the foundation pit,the length of the cantilever section of the continuous wall structure,the embedded depth of the continuous wall at the bottom of the pit and its structural internal force,and optimize the thickness of the continuous wall.The upper part of the rigid connection cushion cap is backfilled with light permeable materials,and drainage holes are set on the front and rear vertical walls of the cofferdam,effectively reducing the thickness and reinforcement ratio of the front and rear vertical walls of the cofferdam.Combined with the construction process of diaphragm wall and cofferdam,large amount of earthwork backfilling and excavation are avoided,and the project cost is reduced.The development of the new cofferdam structure is conducive to solving the limited space construction problems faced by the reconstruction and expansion of the ship lock,and provides reference for similar projects.