When an EPB TBM bores, its cutterhead in front rotates to excavate the soil into the muck chamber. When the chamber is full of mucks, its passive earth pressure is basically the same as the earth and water pressure exerted on the cutting face, resultantly, the balance of the face is realised and maintained (i.e. the face is dynamically stable).

Tianjin Metro Project

silty clay

TBM CREC-01 is China's first self-developed and manufactured mix-type EPB TBM with independent IP rights, which was rolled off the production line in Xinxiang Henan on 25 April 2008 and employed in tunnel works of Yingkoudao Station - Heping Station running interval at lot 10 of Tianjin Metro Line 3, this TBM crossed underneath lots of old-fashioned landmark buildings. Thanks to the good muck reconditioning system, the settlement was controlled with 3mm. The maximum daily advance achieved is 21.6 meters and monthly 560 meters.


Zhengzhou Metro Project

The tunnel of Zhengzhou Metro Line 1 is 1010.90 meters long and the geology thereof is featured by fine sand and silt layers. On 28 December 2009, TBM CREC-02 was launched successfully and then bored safely through Jinshui River. Maximum advance rate made by this TBM reached up to 450 meters per month. The breakthrough for left running tunnel between Zhongyuan Road Station and Zhengzhou Railway Station was eventually completed on 15 September 2010.