1. Project name: Trung Hoa Tunnel of Trung Hoa intersection minor project, Hanoi Ringroad No.3 project, section from Mai Dich to the North of Linh Dam lake

2. Location: Ha Noi

3. Year of commencement: 2014

4. Year of completion: 2015

Highlights of the project

The scope of the project consists of two tunnels in two directions of traffic, in the direction of Thang Long Avenue – Tran Duy Hung str. – Hoang Minh Giam str. Each tunnel has 3 motor lanes wide 3.5m / lane. The length of the underground tunnel is 120m, the open tunnel is 488m and the approach road to the tunnel is 83.8m long. The tunnel foundation structure includes: bored pile foundation structure, reinforced concrete pile foundation structure, shallow foundation structure reinforced with cement reinforced soil pile constructed by high-pressure jet drilling technology.

Description of advanced science, technology and software application

According to the plan, along the route Tran Duy Hung str. – Thang Long Avenue has urban railway No. 5 of Hanoi City at a depth of ~ 16.0m under the ground. Trung Hoa Tunnel is located at a depth of ~ 10.0m under  the ground. Thus, this railway line will be located under Trung Hoa Tunnel, the distance from the top of the future railway tunnel and the bottom of Trung Hoa Tunnel will be ~ 5.0m. The process of constructing the tunnel of the future railway (drilling) will affect Trung Hoa tunnel by causing subsidence of loose soil layer at the bottom of the tunnel and affecting the stability of the tunnel.

Therefore, it is necessary to have solutions to enhance the cohesion of the loose soil layer at the depth from the bottom of Trung Hoa tunnel to the depth of the TBM tunnel and to facilitate the drilling process to dig the TBM tunnel in the lower layer

At the bottom of Trung Hoa tunnel, there are mainly loose soil layers, so the TBM drilling will cause the subsidence when affecting the stability of the tunnel. On that basis, during the design process, TEDI collaborated with OC Company to calculate and use this method of cementing the bulk materials, increasing the adhesion of the material to create stability for the Trung Hoa tunnel and enhance stability when executing TBM drilling. Jet-grouting method is applied in construction.