【HaiChuan Civil Engineering Issues】Understanding the Importance of Proper Foundation Excavation from the Chengdu Metro Tunneling Incident

In accordance with the relevant provisions of the Building Law of the People’s Republic of China and the Regulations on Quality Management of Construction Projects, the project owner and the construction contractor must carry out construction strictly in accordance with the construction plans and drawings approved by the housing and urban-rural development authority; they are not allowed to modify the engineering design on their own, including the design drawings and construction technical standards. If the reason of \"not constructing in accordance with the approved plan and arbitrarily adding more dewatering wells on site\" is true, the construction entity, Chengdu Airport Xingcheng Investment Group Co., Ltd., may face administrative penalties such as orders to make corrections and fines ； In addition to being ordered to make corrections and fined, the construction company Sichuan Highway and Bridge Construction Group Co., Ltd. shall also be responsible for carrying out rework or repairs if the quality of the construction project does not meet the specified standards, as well as compensating for any losses resulting therefrom ； In severe cases, the entity may also be ordered to suspend operations for rectification, have its qualification level reduced, or have its qualification certificate revoked. As for whether this accident will be classified as a major liability accident, it remains to be determined by the relevant authorities. If it is determined to be a major liability accident, the relevant responsible persons may face administrative sanctions; in cases of serious circumstances, they may also be held criminally liable. Those who cause losses shall also bear liability for compensation in accordance with the law. Furthermore, during the construction process, there is a supervisor acting as a third party; it is also very important to determine whether this supervisor has fulfilled their supervisory duties properly.

Netizen comment: Stop scaring people! Take out the drawings; it is necessary to review the original documents containing both text and images, and to verify the design elevation, the elevation of the reference points, the construction elevation, and the elevation of the points where damage occurs – all of these need to be thoroughly investigated. First, determine to whom the responsibility naturally belongs, and then discuss the allocation of responsibilities.

Netizen comment: Before construction, the client is responsible for the accuracy of the information provided regarding the underground pipelines; if construction is carried out based on that information, the construction company bears no responsibility. If the construction company proceeds with work beyond what is indicated in the information, it bears full responsibility.

Netizen comment: Maybe the subway isn’t following the route approved according to the plans? Don’t be so sure it’s the contractor’s fault. Rainfall construction plans are all reviewed by numerous experts; unless the construction party is poorly managed and fails to follow the plans, the probability of such incidents occurring is very low

Nanning had an even more severe incident: at 15:42 on the 22nd, while Guangxi Sinochem Mingda Survey and Design Co., Ltd. was carrying out survey work at the construction site of Road 24 in the Fengling area of Nanning, a drill bit with a diameter of 9 centimeters penetrated the tunnel of Metro Line 1, entering it by 98 centimeters before coming into contact with a train that was in operation at that time.

Relevant authorities stated that carrying out construction projects within urban rail transit protection zones could affect the safety of urban rail transit. Therefore, when carrying out construction activities that may affect the safety of rail transit within the protected areas of urban rail transit, the undertaking party shall formulate safety protection plans and monitoring plans ； Construction activities have a significant impact on the safety of urban rail transit; if the construction or operating entities of urban rail transit deem it necessary, the carrying out of such activities shall be entrusted to a qualified institution for a safety assessment ； The safety protection plan, monitoring plan, and safety assessment report shall be copied to the urban rail transit construction or operation entity prior to commencement of work. Where relevant operations require relevant administrative permits, the permitting authority shall seek the opinion of the municipal transportation administration department prior to granting the permit.

The relevant provisions of the \"Regulations on the Management of Urban Rail Transit Operations\" have specified the scope of the subway protection zones as well as the safety management requirements. Among them: Article 20 Urban rail transit systems shall establish control zones within the following areas: (1) Within 50 meters on the outer side of underground stations and tunnels ； (II) On ground-level and elevated stations, as well as within 30 meters outside the outer edge of the track lines ； (III) Within 10 meters outside the outer boundary of buildings and structures such as entrances and exits, ventilation booths, and substations. Article 21: When carrying out the following activities within the control and protection area of urban rail transit, the undertaking unit shall formulate a safety protection plan and, after obtaining the consent of the operating unit, go through the relevant administrative approval procedures in accordance with the law: (1) Constructing, expanding, renovating, or demolishing buildings and structures ； (II) Laying pipelines, excavation, blasting, foundation reinforcement, well drilling ； (III) Sand excavation and river dredging in the cross-river tunnel section ； (IV) Other activities that result in significant increases or decreases in load.

According to a report from Nandu News, by reporter Zhong Liting and correspondent Zhang Xilong, with assistance from Xuan Huiming, Guangzhou Metro recently announced an incident of illegal drilling carried out above the tunnels used by Line 6. It is reported that this construction activity was part of an elevator installation project, and the drilling took place right above the tunnel of Line 6 of the subway. Fortunately, it was detected and stopped in time by inspectors from the subway’s safety department; otherwise, the tunnel on Line 6 could have been drilled through during operating hours, leading to serious safety accidents such as damaged vehicles and casualties.