The first case in the country! China Railway 14th Bureau's Large Shield "Crossing the City" Sets a New Record

urban buildings, there are many supporting structures deep underground, which are often avoided and protected in shield construction.

But, what if we really meet? Will these support structures hinder the progress of the tunnel, and will shield tunneling affect the buildings above? 30 P. M. on

May 27, the shield machine of the West Line Shield Tunnel of Guangzhou Haizhuwan Tunnel Project, which was invested and constructed by Guangzhou Trading and Investment Group and constructed by the 14th Bureau of China Railway, successfully passed through the China Nuclear Business Building and other buildings, marking the successful completion of the construction of the first super-large diameter shield grinding pile group in China. It also provides a valuable case for China's urban shield construction. Location Map

of

China Nuclear Business Building 67 "steel nails" block the way of the shield, how does the shield construction protect the building above?

China Nuclear Business Building is a six-storey frame structure building. The shield of the west line passes through the building immediately after starting. Within the scope of excavation, there are 67 pile foundations, which are stuck underground like "steel nails" and intrude into the tunnel for about 7 to 9 meters, causing serious obstacles to the shield construction.

"The original design is to demolish the China Nuclear Business Building, and then the shield machine will go down." Huang Shuhua, chief engineer of the project, introduced that in order to minimize the demolition and construction, through the comparison and selection of schemes and expert discussion, it was decided to adopt the "in-situ protection" scheme for the China Nuclear Business Building through the innovation of technology and construction methods, to underpin the underground pile foundation, and to establish a new force underpinning body to ensure the structural stability of the building. For the first time

in China, many measures have been

taken to excavate the "Big Mac" safely

. In order to reserve space for the 15-meter-class super-large diameter shield machine "Daodao Pioneer", the main beam span needs to be more than 20 meters, and the pile foundation needs to be more than 100. The shield machine needs to carry out large-scale grinding pile construction, including the largest diameter of 1.5 meters of bored piles, which is the first case in the country, and the construction is extremely difficult.

In order to ensure the smooth progress of shield construction, the project carried out the underpinning construction of China Nuclear Business Building one year ahead of schedule, strengthened the appraisal of existing buildings and the investigation of surrounding pipelines, and arranged monitoring points in China Nuclear Business Building. At the same time, an expert review meeting was held to inquire the pulse of the construction scheme for many times and optimize the technical scheme. The average settlement of the expert demonstration meeting on

the special construction scheme of the

shield grinding pile group is only

0.33 mm. Strictly control the parameters of shield tunneling, strengthen the control of grouting, adjust the specific gravity of mud, increase the stability of the tunnel face, and ensure the safety of cutting piles into the warehouse. Huang Shuhua said.

According to the monitoring data, the average differential settlement of houses and ground surface is 0. 33 mm in the process of "Daodao Xianfeng" shield machine passing through, almost without disturbance, which marks the success of the first super-large diameter shield passing through existing buildings and structures in situ protection and grinding pile group technology in China.

Guangzhou Haizhu Bay Tunnel Project runs through Haizhu District and Panyu District, with a total length of 4.35 kilometers, of which the shield section is 2077 meters long, the excavation diameter is 15.07 meters, and the maximum buried depth is 50.64 meters. It is a double-tube shield tunnel and the first super-large diameter municipal shield tunnel in the Pearl River Basin. After completion, the central city of Guangzhou will be directly connected to the South Railway Station in only 15 minutes, which is of great significance to promote the construction of Guangzhou's national central city and the interconnection of Guangdong-Hong Kong-Macao Greater Bay Area.