In recent years there have been many pipe roofing jobs successfully completed in China using Tracto-Technik pipe ramming equipment. In Beijing, with preparations for the 2008 Olympics in full swing, several projects have recently been undertaken.
The latest Chinese developments include projects in Hangzhou Jiefang Road and Shenyang Yunhe and eight projects in the Beijing area, with the total length of pipe rammed being in excess of 30 km.
One example is located at the intersection of the Beijing airport highway and the new light rail train (which connects the city to the new Beijing International Airport), going under the International Rail line from Beijing to Ulan Bator (capital of Inner Mongolia).
The pipe roofing tunnel has a horseshoe shape, the structure size is 11.9 metres wide and 8.475 metres high, with two rail lines passing through, and the depth from the top surface (railway track) to the top of the pipe roofing is 7.2 metres.
The project owner, China Railway Sixth Bureau decided on the TT-Group’s “Koloss” 350 mm ramming machine to carry out the casing installation, and two of the machines were supplied by TT-Group Subsidiary TT Asia Pacific through their distributor in China, McAllen (Tianjin).
McAllen President Wu (Tony) Ying and his team supplied and serviced the equipment throughout the project, ensuring the timely completion as there could not be any delays in the tight pre-Olympic schedule for the development of the light rail.
Another item of TT-Group equipment, the Grundopit 40/60 drilling machine, was used to clean out the installed casings, pipe size being 377 mm diameter with 10mm wall thickness and an interlock system manufactured by local company was used to maintain accuracy.
A computer program was used to do the pipe roofing construction mechanics, and simulation analysis, including qualitative analysis and quantitative analysis to verify the ground sedimentation and construction safety. The program was also used to draw the curve of digging transmogrification, curve of main tunnel finished transmogrification, curve of ground sedimentation and so on.
The construction proposal was prepared including information on pipe roofing technology; mechanics analysis; problems and troubleshooting during construction; length and direction of pipe roofing; obstructions in front of the ramming pipe, such as stone or landfill blockages, and pipe welding.
The project was commenced October 2006 and finished in January 2007.
Thanks to TT’s ramming machines, the unique design, and an experienced contractor, the project was finished on time with excellent accuracy, quality, and no interruption to traffic on the trans Mongolian Railway Line.
Since this project, there are some six pipe roofing projects that have been completed in the Beijing area from March to July of 2007, called Nanshui-Beidiao. These projects carried river water from the south to the north of China, running under railway lines. A total of 22 km of 325 mm steel pipe was used.