Recently, good news of construction progress came from the Dapeng Branch Line of the Shenzhen-Huizhou Intercity Railway: shield tunneling in the section from Yanzihu Station to Kuichong Station has entered the stage of full-scale construction. The first shield machine in Work Area 4 of the Dapeng Branch Line project of the Shenzhen-Huizhou Intercity Railway has been successfully launched.

The first earth pressure balance (EPB) shield machine in Work Area 4 of the Dapeng Branch Line of the Shenzhen-Huizhou Intercity Railway was successfully launched from Kuichong Station, marking that shield tunneling in the section from Yanzihu Station to Kuichong Station of the line (referred to as the "Yan-Kui section") has officially entered the stage of full-scale construction. This has laid a solid foundation for the subsequent construction of the Dapeng Branch Line of the Shenzhen-Huizhou Intercity Railway. The Yan-Kui section in Work Area 4 of the Dapeng Branch Line of the Shenzhen-Huizhou Intercity Railway spans Pingshan District and Dapeng New District of Shenzhen, with a total length of about 6 km.

In order to complete the milestone target on schedule, the project team repeatedly rehearsed the construction plan. After fully studying the geological, hydrological and environmental factors of the section, they invited well-known experts in shield tunneling, geology and equipment to form an expert group. After multiple rounds of demonstration, the scheme of using an earth pressure balance shield was finally determined. Its feature is to establish soil chamber pressure at any time to achieve pressure-maintaining tunneling, which can minimize settlement and reduce impact to the greatest extent.

To meet the schedule requirements, according to the scheme design, the shield section at the large chainage of Yanzihu Station to Kuichong Station adopts two composite earth pressure balance shields for construction, launched from Kuichong Station. The section passes alongside self-built houses, the Fengshushan pedestrian bridge and several houses to be demolished, and tunneling proceeds to the boundary chainage for in-tunnel dismantling. The left and right lines are driven 1,909.6 m and 1,927.6 m respectively.

The minimum curve radius of the section alignment is 1,300 m. The longitudinal slope of the entire tunnel adopts a straight upward gradient, with a maximum longitudinal slope of 3.9%. The maximum buried depth of the tunnel body in the section is about 120 m, and the minimum buried depth is 11.9 m.

This scheme not only reserves sufficient construction time and saves construction investment, but also greatly reduces the safety risks of in-tunnel equipment conversion and equipment tunneling during shield construction.

70% of the shield section passes through karst strata. Improper treatment of karst caves can easily lead to risks such as shield machine dipping and ground collapse. The karst locations in the shield section are on Pingkui Road. Pingkui Road is a main trunk road connecting Longgang District and Dapeng New District. Because lane occupation for construction affects traffic flow, only one lane can be occupied at a time, so karst construction is constrained by various aspects.

To ensure the normal launch of the shield machine and overcome various karst treatment difficulties, the project construction team worked overtime during the lane occupation period and completed the karst treatment construction for the 150 meters before launch in the shortest time.

At the same time, the project held several meetings to sort out issues before the shield machine launch, actively communicated with the equipment manufacturer CCCC Tianhe, the general manager department, the owner unit, etc., achieved prioritized planning, and overcame one by one the difficulties of transporting shield components to the site before the Spring Festival, shield hoisting, split assembly of the shield machine, and large sleeve assembly. The project strictly implemented the requirements of relevant control documents, carried out acceptance work at each stage in the equipment factory, and actively contacted and coordinated the handover of the shield launch site and the entry of the shield machine transportation, hoisting and assembly teams, ensuring that the launch equipment could be installed, commissioned and operated well as soon as possible, thus laying a solid foundation for the smooth launch of the shield machine.