With the completion of a 946m single drive on September 26, the "Jiaoliu" pipe jacking machine, which was built by CRCHI for ultra-complex formation and long and large tunnels, has helped the Jiaoliu River headrace tunnel of the Chaoer-Xiliao water diversion project with a successful breakthrough.

This project has created the record of the longest pipe jacking in the ultra-complex geology and high-water pressure stratum in domestic China, and it is also a great engineering achievement of CRCHI pipe jacking machine following the "Tiejun", the China’s largest domestic pipe jacking machine.

The project adopts a 4.3-meter outer diameter pipe with a single crossing distance of 946 meters and a maximum overburden of 26 meters. The water content in the formation is extremely rich, and the water pressure throughout the construction is more than 2 bar. In the whole section, the rock layer, mud gravel and clay strata frequently alternate, and the strata are soft on the top and hard on the bottom. Under such a condition, the pipe jacking machine is like prowling in the "reef sea area", boring through the strata safely and efficiently with a single drive was a major challenge for a pipe jacking machine.

According to the engineering characteristics and construction difficulties of the project, the whole machine of “Jiaoliu” was adopted with high reliability design, equipped with hard rock heavyduty main bearing, high power density main drive, intelligent monitoring and control system, and independent man lock, which has the ability to cope with various complex working conditions. During the construction process, the construction personnel repeatedly used the independent man lock for conducting hyperbaric cutter head intervention in the unstable formation. The powerful configuration and high stability of the equipment ensure the smooth breakthrough of the project, and the maximum daily advance of 15 meters and the maximum monthly advance of 219 meters have been achieved.

http://en.crchi.com/art/2023/10/26/art_40592_4648368.html