| In general,the eastern region in China is more developed than other regions.A large number of urban rail transit facilities are under planning or constructing due to the economic development.Because of its high efficiency and small influence on ground traffic,shield tunneling method is more and more popular in urban rail transit construction.Soft soil is widely distributed in the eastern region,while the poor engineering characteristics of soft soil have brought a great challenge to the construction and operation of shield tunnel.Therefore,it is very important to monitor the shield tunnel in soft soil area.Based on the new monitoring methodology and monitoring system,this paper sets up a monitoring scheme for shield tunneling in soft soil area.The new monitoring methodologies are optical fiber sensing,wireless sensor network and laser ranging.The monitoring scheme proposed two monitoring methods,which are based on distance measurement and strain measurement.The monitoring system for shield tunnel in soft soil area are developed by MATLAB.The main achievements were as follows:(1)This paper summarizes the research background of shield tunnel monitoring in soft soil area and introduces the research progress of the common shield tunnel disease,monitoring methodology and shield tunnel monitoring system at home and abroad.The discussion expounds on the importance of the shield tunnel monitoring in soft soil area.(2)Based on optical fiber sensing,wireless sensor network and laser ranging,this paper introduces the new monitoring methodology for shield tunneling in soft soil area.Measuring principle and technical parameters of fiber Bragg grating sensor,wireless strain sensor and laser ranging sensor are showed in details.Applicability and reliability of these sensors are verified through a series of indoor tests.(3)The monitoring system of shield tunneling in soft soil area was developed based on MATLAB.The interactive software interface enables user to do data mining,data visualization and monitoring alarm.The monitoring system can identify a variety of sensor data and perform two-dimensional and three-dimensional data visualization.Its useful data mining module provides data identification,denoising and prediction functions.Combined with the current monitoring standard,the practicality of system has been greatly improved.(4)Based on distance measurement and strain measurement,the monitoring scheme of shield tunneling in soft soil area is proposed,which includes sensor layout and monitoring theory of two monitoring methods.To verify the feasibility of the monitoring scheme,a large number of simulated calculation was carried out based on the characteristics of three new sensors.The work flow and visualization result of shield tunnel monitoring system in soft soil are introduced,which shows the efficiency and convenience. |
