Han Ximin

ximhan@126.com

A DRILLING job for a housing estate at the construction site of Shenzhen Bay Super Headquarters in Nanshan District broke through the tunnel of Metro Line 9, causing a mud cave-in into the tunnel Saturday night.

Thanks to the alert from Metro train drivers, who spotted the abnormal situation and reported it to the commanding and maintenance teams, the Metro avoided further damage.

The incident happened at the 2-o’clock position of the tunnel, which is around 800 meters from Shenwan Station toward Shenzhen Bay Park Station.

The Metro operator cleared a total of 120 bags of mud from the tunnel and sealed the hole with cork and steel boards.

A preliminary investigation showed the contractor of the housing project had violated rules and started drilling prior to applying for approval.

According to Peng Tienian, workshop director of the No. 3 engineering department of maintenance center, the Metro operator will fill the hole with concrete from the exterior ground and reinforce the hole from the interior tunnel.

To ensure safety, the operator will arrange an inspection and set the speed limit at 45 kilometers per hour on the first train running to Wenjin Station between Sunday and Nov. 5.

This wasn’t the first such incident. The tunnel for Line 5 between Linhai Station and Qianhaiwan Station was pierced during an exterior project April 28, 2016. The contractor hadn’t applied for approval from the Metro operator.

According to regulations on the city’s rail transportation management, contractors within the Metro operation areas must apply for written approval from the Metro operator before commencing drilling work.