A tunnel is an engineering building buried in the ground and is a form of human use of underground space. With the development of China's market economy, the number of road tunnels and the scale of construction are getting larger and larger, and there are more and more safety hazards and management challenges inside the tunnels. How to strengthen the safety management of tunnel personnel and enhance project safety control is an important issue that needs to be addressed in tunnel safety construction.

【Project Background】

The Beijing East Sixth Ring Road into the ground project is a landmark project for the construction of Beijing's skeleton. The total length of the tunnel reaches 7341m, and the longest distance of one continuous bored tunnel reaches 4770m, which is one of the longest continuous bored tunnels in China with large shield structures. The design section diameter of the tunnel is 15.4m, and the diameter of the tunnel excavated by mud and water balance shield is 16.07m, the tube sheet is 65cm thick and the single sheet weighs 16.9t, which is the largest in the field of urban road shield tunnel in China. The project is located in the core area of the sub-centre and crosses many roads, railways, rivers and underground pipelines, with a total of 115 risk sources above risk level III in the design risk assessment, including 6 special risk sources. The project is political, social and economic in nature, carrying strong regional functions and people's well-being.

【Project Management Pain Points】

Shield tunnels are engineering structures buried in the ground. The construction environment inside the tunnels is difficult, with narrow passable lanes and a high risk factor, and the management cannot keep track of the tunnels in real time. Inadequate management in tunnel infrastructure construction, construction and management face various challenges:

staff management: the number of people entering and leaving is counted through gates at the entrances, and real-time operations are viewed through cameras near the palm faces; the actual location of personnel in the tunnel cannot be accurately grasped, and on-site supervision is not in place.

emergency management: when personnel encounter an emergency, they can only call for help through the emergency telephone; early warning through the traditional form of radio, once an accident occurs, it is impossible to obtain the location of the personnel in the first place, missing the best rescue time.

Attendance management: Attendance statistics for operators are cumbersome, with errors and omissions, and accuracy and efficiency cannot be guaranteed.

Dangerous operation management: The tunnel has narrow passable lanes, difficult to stagger, many people and vehicles, high risk factor, unable to grasp the work status of construction personnel, vehicle location and access to the tunnel in real time.

【Project Details】

Combining the current situation of tunnel construction and the pain points of the construction and management of the Beijing shield tunnel project, Wuxu Communications and the client decided to adopt the UWB high-precision positioning technology solution after several rounds of program design and discussion, by deploying UWB positioning anchors in the construction area to accurately locate the working personnel and vehicles in real time. It realizes intelligent safety management of personnel and vehicles in complex working environment, intelligent construction of shield tunnel, optimizes construction operation, helps shield tunnel construction and management to be knowable, visible, traceable and controllable safety prevention and control system, effectively solves the difficulties of safe construction management of shield tunnel, and promotes the parallel construction of tunnel wisdom and safety.

【Technical Comparison】

UWB high-precision positioning system mainly consists of hardware (anchor, tag), positioning engine software (C/S architecture), and API interface. By accurately measuring the propagation time of wireless pulses in space and measuring the absolute distance between the tag and the anchor, it can achieve up to 10cm level positioning accuracy to achieve accurate positioning of employees in the tunnel. It can solve the problem of safety control of personnel and vehicles in the complex environment of construction.

【System functions】

01 Real-time positioning in a complex environment

With Woxu's personnel safety management solution, we can obtain the precise location of the workers in the cave in real time and accurately count the number of workers in the cave. It can also query the actual location, activity trajectory and identity information of one or more people according to conditions such as region and shift, and clearly locate the current position of staff; in the real-time position, it can display the real-time direction of vehicles, and count the total number of vehicles in the tunnel and the number of vehicles that are entering/exiting the tunnel; the shield tunnel is divided into parts to count the density of personnel, which is displayed in layers. The safety construction and control capability is greatly enhanced by the realisation of safe and controllable personnel and vehicle work, data visualisation presentation, etc.

02 Dynamic electronic fencing

All vehicles automatically generate dynamic electronic fences, when the distance between people and vehicles, vehicles and vehicles is less than the set threshold, the anti-collision alarm will be triggered and the system will alert the personnel and vehicles. The positioning tags worn by personnel vibrate to quickly remind the designated personnel or all personnel, aiding the broadcast to achieve accurate warning functions. The warning distance between "vehicle and vehicle" and "person and vehicle" can be set individually.

03 Vehicle density warning

The safety management team can determine the direction of the vehicles according to the direction of the tunnel entrance and see in real time how the vehicles are entering and leaving the tunnel. When the density of vehicles in the tunnel, the density of vehicles entering the tunnel and the density of vehicles leaving the tunnel reach a certain threshold, an alarm is issued to drivers who are in the tunnel and are ready to enter the tunnel. It is convenient for safety management personnel to make unified management arrangements for vehicle order.

04 SOS one-key rescue

When encountering an emergency, staff can use the SOS button on the positioning tag to make a quick distress call, and the system automatically determines the location of the personnel in the alarm area, thus realising the dispatch of rescue forces in the vicinity and rapid response, and avoiding accidents to the greatest extent possible. In addition to real time positioning, the Woxu smartwatch wristband tag can also monitor personnel vital signs, further enhancing personnel safety monitoring and management.

05 Efficient personnel management

The UWB positioning system is integrated with the tunnel access management system to provide real-time statistics on the number of people in the cavern, the number of people on the palm face and the number of people in the second lining, to achieve accurate attendance statistics, reduce the workload of manual statistics and improve the accuracy of data. To address the problem of personnel arrival in place cannot be effectively monitored and counted, the system can accurately record the time of staff entering and leaving the work area through positioning tags, realise the automatic attendance roll call and working hours statistics of personnel, comprehensively record the working condition of staff, and facilitate the management personnel to inquire and manage. The system supports the creation and export of information reports, such as attendance, working hours, absence reports, etc., to achieve the improvement of work efficiency.

【Anchor installation】

【Case Value】

The trend of tunnel safety management is to use IOT technology to anticipate, prevent and stop safety accidents from happening, by using Woxu's UWB positioning system to establish an intelligent management platform that integrates "location information + area warning + data statistics + danger rescue", the Beijing East Sixth Ring Shield Tunnel project has achieved precise positioning and management of employees and vehicles, significantly improving the efficiency of the project. The project has achieved accurate positioning and management of staff and vehicles, significantly improving the safety construction and efficient management of the tunnel. Currently, Woxu's high-precision personnel management and positioning system has been successfully applied in many tunnel projects across China. In the future, Woxu will help tunnel projects gradually form a "standardized, visualized, transparent and intelligent" construction to realize their safe and efficient operation.