80 days in advance! Five new wet spray robots help Zhangjiayuan tunnel to overcome world problems

On July 27th, the first special tunnel of the Mongolian-Shantou section of the Menghua Railway was built by the China Railway Construction 18th Bureau Group. The Zhangjiayuan tunnel passed through 80 days in advance and successfully tackled worldwide problems such as collapsible loess subsidence. Railways in the Mongolian and Shaanxi section laid a good foundation.

Zhangjiayuan Tunnel smoothly passes 80 days in advance

Starting from the Haole newspaper station in Inner Mongolia Autonomous Region and ending at the Ji’an station in Jiangxi province, the Mongolian-Huanghua railway linking the “Golden Triangle” of Mongolia, Shaanxi and Gansu Energy with the Hubei province, etc., is 1,837 kilometers in length. It is the largest coal carrier in China. The special line and the new national strategic transportation channel of “Northern Coal South” are also the longest heavy-duty railways built in the world.

Zhangjiayuan Tunnel is located in Pingqiao Town, Ansai District, Yan'an City, Shaanxi Province. It has a total length of 6,288 meters. It is a single-hole double-track tunnel with a maximum depth of 195 meters and a minimum depth of 8 meters. Gao Shuangtao, commander of the China Railway Construction 18th Group’s Menghua Railway Command, introduced that the surrounding rock of the tunnel entrance, exit, and inclined incline are all grade V, and that the hole passes through shallow eolian loess, collapsible loess, and earth and rock. The geologic structure is particularly complex due to the unfavorable geology such as the detrital crush zone, water-rich sandy loess and water-rich sandstone. In the Zhangjiayuan tunnel excavation, it passes through the shallow buried gully section 6 times. The width of the bottom of the trench is 4-8 meters and the depth is 8 to 27 meters. It is easy to cause geological disasters such as roof collapse and large deformation during construction. The construction difficulty and risk are very large. .

In order to overcome the world's problems such as subsidence of collapsible loess, and faced with complex geological conditions, Hui Wuping, manager of the Menghua Railway Project Department of the China Railway Construction 18th Bureau Group, explained that they have implemented factory processing of finished products and mechanization of construction. The construction team’s specialization, monitoring and measurement informatization and other four modernization managements follow the guidelines of “advanced management, strict grouting, short-feeding, strong support, quick closure, and ground measurement” and adopt micro-step excavation method to shorten the length of each step. , Closed the loop from the back arch to the maximum distance of no more than 12 meters from the face to incorporate the process management, so that the tunnel deformation control is effective, while safety and schedule controllable.

They carried out technological innovations for the foundation reinforcement of collapsible loess after excavation of the tunnel. By rationally selecting compaction tools and hammer weights, they solved the problem of small and undetectable space within the tunnel and ensured quality and progress. In order to ensure the strength of newly-supported concrete, the tunnel uses five new wet-spraying robots to achieve a 100% pass rate for the strength of the first-stage concrete, and at the same time, it can quickly seal the face of the hand and avoid collapse caused by excessive exposure of the surrounding rock.

Five new wet spray robots help Zhangjiayuan tunnel to overcome world problems

In addition, the promotion of the protection of carbon dioxide welding was strengthened, and the weld seam was full, smooth, consistent in depth and depth, and was well received by the owners. It actively promoted the first project and the “Model Guide”, and improved the overall level of its quality and safety management through mutual observation, learning, and communication among the participating parties.

To create the Great Wall for Engineering Safety, Gu Zhenwei, secretary of the Party Work Committee of the China Railway Construction 18th Bureau Group's Menghua Railway Headquarters, said that the headquarters and project departments have built a strong security line and adhered to the safety baseline to actively carry out the “implementation” implemented by the Menghua Railway Company. Responsibility for the main body, the creation of a unit of integrity, and the "team leader responsibility system" and other "combination punches", the work class management system and the team leader quality responsibility system have been formulated, and economic rewards and penalties and accountability have been used to give the work team a full advantage. Adding a "sweeping spell" to create a first-class quality project "strengthening the foundation."

It is reported that the current construction and production of the MHTJ-5 tender section of the Menghua Railway undertaken by the China Railway Construction 18th Bureau Group has been steadily progressing. While achieving “zero safety accidents, zero defect quality, and zero pollution to the environment”, the progress of the construction line is at the top and won the award. In 2016, the “Advanced Group of Menghua Company's Mongolian and Shaanxi Command” and the 2016 “Tianjin Labor Competition Typical Unit” were honored. (This article is from Wuxin Tunnel)