吹填深厚超软土地基加固现场试验研究

Experiment research on hydraulically filled ultra-soft soil ground improvement

为解决砂资源紧缺情况下高含水率、大面积吹填超软土真空预压地基加固技术难题,在南港进行13.8万m2现场试验,开发了一种适合表层为深厚吹填超软土、下层为深厚沉积欠固结土地基的无砂二次真空预压地基处理技术。该技术在浅层真空预压加固中采用较小的排水板间距,使超软土快速形成满足深层插板机械施工的硬壳层,取消了传统工艺中作为施工垫层的粉细砂垫层,并提出了浅层加固的卸载标准;在深层加固时取消作为排水垫层的黄砂垫层,由排水板与滤管有效连接形成的管网作为抽气排水通道,实现了完全无砂超软基真空预压地基加固,加固效果满足设计要求。

In order to solve the problems in high water content and large area reclamation of ultra-soft soil vacuum preloading foundation reinforcement technology with sand shortage, we carried out an in-situ experiment with 138 000 m2 site, and proposed a secondary vacuum preloading technique without sand. This technique applies to the ground which the upper part is ultra-soft soil and the lower part is under-consolidated soil. In shallow ground improvement, this technique use smaller drainage plate spacing to form a crust quickly which meet the requirements of deep inserted plate mechanical construction,excluded the silty fine sand used as sand mat, put forward the unloading criteria of shallow reinforcement. In deep ground improvement, excluded the sand cushion used as drainage cushion, used pipe network composed of drainage plate and pipe as suction drainage channel. No sand is needed for foundation reinforcement using this technique and the reinforcement effect meets the design requirements.