压砂法施工沉管隧道砂垫层的抗液化研究

Research on Anti-liquefaction about the Sand Cushion of Submerged Tunnel Constructed by Sand-flowing Method

沉管隧道砂垫层基础的抗液化问题是沉管地基处理关键技术之一。地震砂土液化是一个实际工程问题,一旦发生液化会给地下工程结构带来巨大灾害。我国的水工建筑物抗震设计规范规定了饱和砂土在不同地震烈度时可能发生液化的相对密度值。但由于沉管隧道砂垫层基础是在水下施工,施工时相对密实度不易控制,如果按规范取值会偏大,造成巨大浪费。本文通过对沉管隧道砂垫层抗液化分析并结合工程实例提出了砂垫层施工时应达到的合理密实度。

The anti - liquefaction about the sand cushion of submerged tunnel is one of the key techniques in the ground treatment. Liquefaction of sands during earthquake is such an actual problem that it will bring a large disaster if suffering liquefaction. It is prescribed in the code for design of underwater structures that when the saturated sands will become liquefiable under different intensities. However it is difficult to control the compactness val- ue in construction because the sand cushion is laid in water. There will be a large waste if selecting the compacthess value by the code. Based on the anti - liquefaction analysis on the sand cushion of submerged tunnel and practical project the reasonable compactness value which should achieved during construction is advised.