CRCHI firstly exports its shield tunneling machine
Reporters learned from China Railway Construction Heavy Industry Co., Ltd. (CRCHI) in Changsha Economic Development Zone on Aug 8 that the tunnel boring machine (TBM) that was independently developed by the company had firstly been put into use in a water diversion tunnel project in southwest Iran on the morning of Aug 6 (Iran Time). This is the first time for CRCHI to export its TBM to overseas markets, which was put into use in the practical engineering project.
With complete independent intellectual property rights, TBM has an excavation diameter of 5.56 meters, total length of over 300 meters, and total weight of about 1,300 tons. The construction spot is located in hilly areas with scarce vegetation and complex geology. The tunnel has a length of 12 kilometers, and its overall stratum is made up of mudstone, sandstone, or their cross stratum, among which mudstone accounts for over 70%. The execution conditions are very poor. On the one hand, TBM’s cutterhead is easy to be pasted if working in mudstone stratum for a long time; on the other hand, they work in an environment with high temperature and high water temperature of the local summer, during which the highest daytime temperature hits 60℃ and the highest night temperature reaches 40℃.
In order to solve these geological and environmental problems and make TBM tunnel faster, the CRCHI project team adjusted measures to local conditions and redesigned the cutterhead foam and bentonite system, and successfully solved the “clay pasting cutterhead” problem in the working environment of mudstone stratum.
By Han Xu
Source: Changsha Evening News