Ensure the safety of the Xiang’an tunnel
7 min readThe highest number of constructors during the Xiangan Tunnel construction was over 4,000.During the construction of such a large project carried out in complicated geological conditions, an example was set for construction safety: no deaths.
The most valuable thing in the world is life. In this regard, the Xiangan Tunnel project was truly a good example.
The workers, who had participated in many major construction projects, felt strongly that thiswas the only project that they had ever worked on that had no time limit. During the Xiang’ an Tunnel construction, no leader or department ever urged them to speed up. This project was meant to take four years to complete, but after they encountered the weathered slot, the construction slowed down. However, still no one urged them to speed up construction. In the end, the project was completed eight months behind schedule. What is time though? Some say that time is money. But during the Xiangan Tunnel construction, time was life. Nothing is more important than human lives.
From the very beginning of the Xiangan Tunnel construction,a guiding ideology had been determined: Security is above all else; quality is more important than life; prevention is better than remediation; responsibility is heavier than Mount Tai(a mountain in China’s Shandong Province).These words were plain, but supremely important!
Early in the preliminary research stage of the project, taking into consideration the key points, difficulties and characteristics of undersea tunnel construction, the safety management planning centered on systematic risk assessment. The domestic and foreign professional advisory bodies and experts were organized to conduct studies and discussions. The “Xiangan Tunnel Project Risk Assessment and Analysis Report”was developed, which laid a solid foundation for security risk management.
This people-oriented method of work also coincided conveniently with the scientific development approach.
Safety comes from an organization and team that has strict discipline. The Vice Mayor, who had long-term experience in project construction and the experience of the Haicang Bridge’s construction, acted as the head of the leading group of the Xiangan Tunnel Project. The headquarters system was adopted for the organization of the construction work, with the General Manager of Xiamen Road & Bridge Group Co, Ltd. acting as the Commander. There was also the Deputy Commander. The strict responsibility system was also adopted.
In addition, during the construction, the Academicians Sun Jun, Zhang Chuhan, Song Zhengi from the Chinese Academy of Sciences were invited to guide the construction, and to make suggestions on the solutions and the key technologies.
The construction units were selected through national tender in accordance with the principles of being”fair，just，open，and honest”.In the bidding stage，after combining the construction technologies for the mountain and river tunnels，and the unique characteristics of this project，aspecialized”Project Safety Construction Manual”was prepared.It had detailed regulations on the safety requirements，safety precautions and disposal measures for various construction scenarios for the different stages，sections and processes of the project.It also defined four strict “combinations of conditions” to select the most experienced domestic construction units in possession of the most advanced technologies.The selected construction units were all in the Chinese construction elite.
The strong leadership，the outstanding experts and the well-trained construction teams provided an important foundation for safety during construction.
After construction started，the construction safety regulatory philosophy was always adhered to throughout the whole construction process.The construction teams earnestly implemented the safety guidelines of”safety first，prevention first and comprehensive management”，to truly achieve “strict standard，strict technology and strict discipline”.
A brand new type of organization and system had been established during the safety supervision in the Xiangan Tunnel construction.The owner set up the Safety Construction Supervision and Management Office，”Safety Supervision Office”for short.The experienced experts in the construction safety field took charge of the safety construction supervision work.
“The Safety Supervision Office had the right of a one-vote veto’and the power of reward and penalty.”The Safety Director Wu Shishu said，”If there was a potential safety hazard，with a veto from the Safety Supervision Office，the construction unit must work to rectify it.In the earlier stage of the construction，this item was included in the tender document as one of the safety management approaches.”
It is particularly worth mentioning that，a total of 76 safety management personnel in possession of the”Safety Production Examination Certificate”were working at all levels of the safety supervision organizations in the Xiang’an Tunnel construction.Among them 11 were senior engineers，23 were engineers，34 were skilled workers，and 8 were safety records archivists.In addition，the project managers of the construction units sent 54 part-time security officers to the construction teams.In the specific works，these safety construction supervision personnel were impartial and incorruptible and they strictly carried out the supervision and management and made clear requests.
A brand new safety supervision network had been established:a safety supervision organization constituted by three levels of units，including the owner units，the supervision units and the construction units.A total of 96 full-time（and part-time）safety management personnel were working in these units.They carried out the safety management work conscientiously and carefully.Each of them performed their respective duties and they never missed the details.
Safety is not just a concept.It also needs necessary technical support and protection.Scientific and advanced geological forecasts can provide an important basis for the development of safety engineering and construction schemes.Wu Shishu said，”For example，during construction in the poor geological conditions, the construction was carried out in strict accordance with the principle of short footage, weak blast, fast shotcrete, strong support, frequent mensuration, and early closurel.Experts were organized to evaluate the grouting effect and special construction schemes.”
Water inrush prevention devices, water dams, borehole water inrush prevention devices, adequate drainage pumping facilities, rescue machinery and equipment, life jackets, sandbags, and other emergency relief supplies were installed in Xiangan Tunnel, which were all part of the safety hardware inside and outside the tunnel. With these measures, even if there was an emergency, it could be contained and resolved in a timely manner.
The constructors’ concerns for the potential risks in the undersea tunnel construction were mainly reflected with the strict requirements and the construction plan details.
In the tunnel, cameras and other special equipment can be seen everywhere. They constituted the modern emergency alarm system and safety instruction warning system which could immediately activate the emergency rescue plan. By using the safety supervising imaging system, the safety construction conditions on the working face could be supervised and inspected in the management room outside the tunnel. In order to keep the lines of communication open, China Mobile and the construction units jointly installed the mobile communication extension system.Even in the construction site 70 meters below the sea level, cell phone signal was available.
Nothing is trivial in when it comes to safety in construction. Pan Jianli, Vice Commander ofChina Railway 18th Bureau Group, said,”Electronic chips were implanted in the constructors’helmets. It can monitor the identity and actions of each constructor in the tunnel, in order to avoid accidents.”
Meanwhile, an emergency escape routes indication system was laid in the tunnel, and the emergency lights and exit signs were installed, which improved the audio and light safety instructions in the tunnel. In summary, necessary and careful measures were taken to deal with all conceivable circumstances.
In addition, the construction unit also set up a safety production award fund of 4.6 million Yuan, established the safe production assessment system with strict rules for reward and punishment, carried out in-depth construction safety measures, and repeatedly conducted safety drills to eliminate the potential risks right from the start.
According to statistics, during the construction stage, comprehensive investigation and rectifications in response to accident potentials and specialized investigations on potential safety hazards were carried out 55 times and 11 times respectively. In these investigations,9,186 items of accident potential and 201 unsafe behaviors in safety supervision were discovered. They were all rectified in accordance with the principle of “three confirmations and one implementation”, and the rectification rate reached 100%. The potential safety hazards and risk factors were extinguished in a timely manner. The casualties and accidents were effectively avoided.
In the construction, the relevant departments of the Xiamen Municipal Government and the construction units organized up to 10 emergency rescue plan drills according to the actual progress of the project:5 on-site exercises of the excavation tunnel face collapse plan,2 on-site exercises of the sudden water gushing plan, and 3 on-site exercises of the anti-typhoon plan. After each exercise, the evaluation was conducted based on the performance during the exercises in order to identify and summarize the problems and deficiencies. After that, the technical personnel were organized to modify, replenish and maintain the plan, in order to ensure the timeliness and feasibility of the emergency rescue system.
Afull, three-dimensional, secure network for the whole safety process was carefully woven together. Achieving effective safety controls had effectively promoted the smooth construction of Xiangan Tunnel. The 1,694 days of continuous safety implementation measures had achieved thesafety supervision objective of “No deaths”, which set a new record in the history of safety supervision during undersea tunnel construction.
