德寿宫遗址展示工程永久防渗墙的研究与应用

Research and application of permanent cutoff wall in Deshou Palace site

潮湿地区遗址保护的关键是控制地下水并建造可靠的永久防渗墙。渠式切割装配式地下连续墙(TAD)是在渠式切割水泥土连续墙(TRD)内插入混凝土预制板材,为"三明治"结构。且预制板材横向采用榫卯连接,竖向采用螺锁式机械连接,形成连接可靠、具有较好刚度的钢筋混凝土连续墙。结合杭州南宋德寿宫遗址展示工程,介绍了永久防渗墙的设计思路、方案比选和结构构造。通过试成墙试验和现场应用,渠式切割装配式地下连续墙作为地下永久防渗墙具有施工快速、微扰动、止水可靠等优点,墙边土体最大水平位移小于5mm。四周的渠式切割装配式地下连续墙、顶部的上部结构屋盖和底部的中等风化硅质白云岩组成的封闭式止水帷幕,可隔断遗址和外部的水联系,可为我国潮湿地区遗址保护提供新的防渗墙形式。

The key issue for site protection in wet areas was to control ground water and build reliable permanent cutoff walls. Trench cutting assembled diaphragm wall(TAD) had a sandwich structure by inserting concrete prefabricated plate into trench cutting re-mixing deep wall(TRD). The precast concrete plate was connected by mortise-tenon joint horizontally while connected by socket and spigot joint vertically to form a reinforced concrete continuous wall with reliable connection and good stiffness. Based on Southern Song Dynasty Deshou Palace site exhibition project in Hangzhou, the comparison of different types and construction methods of permanent cutoff wall was presented, which proved by trial-wall test and field application. Trench cutting assembled diaphragm wall had the advantages of rapid construction, weak disturbance and reliable performance as underground permanent cutoff wall. Maximum horizontal displacement of soil around wall was less than 5 mm. The waterproof system, composed of surrounding trench cutting assembled diaphragm wall(TAD), the superstructure roof at the top and the moderately weathered siliceous dolomite at the bottom could cut off the water connection between the site and the outside, and could provide a new form of anti-seepage wall for the protection of the site in the humid area of China.