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Principles and Application of a Smart Tunnel Laser Convergence Gauge for Monitoring Tunnel Crown Settlement
(1 Department of Geotechnical Engineering, School of Civil Engineering, Tongji University, Shanghai 200092; 2 College of Civil Engineering, Shaoxing University, Shaoxing 312000)
Abstract Monitoring tunnel crown settlement is a way to evaluate the stability of surrounding rock during tunnel construction and to ensure tunnel construction safety. However, it is difficult to operate a grade rod for the precise leveling instrument and it is quite intense work. Though total station trigonometric leveling can be accurate to a millimeter, it is not often applied in engineering. In order to improve the efficiency of crown settlement monitoring in tunnels, non-contact measurement using a smart tunnel laser convergence gauge to monitor tunnel crown settlement is proposed, and the monitoring steps are briefly introduced in this paper. Through theory analysis, the repeated monitoring and measuring tests both in the laboratory and onsite indicate that the precision of crown settlement monitoring using the smart tunnel laser convergence gauge can reach 0.70 mm. Compared with results from a DS05 percussive leveling instrument and a Leica TS15 total station on the construction sites of a cavern project in the Qindao and the Dangjinshan tunnel on the Dunge railway, the monitoring accuracy and stability of the smart tunnel laser convergence gauge are verified. The application prospects are vast using the smart tunnel laser convergence gauge to measure and monitor tunnel crown settlement thanks to its reliable precision, high efficiency, minimized construction disturbance and ability to simultaneously monitor peripheral convergence.
Abstract：
Monitoring tunnel crown settlement is a way to evaluate the stability of surrounding rock during tunnel construction and to ensure tunnel construction safety. However, it is difficult to operate a grade rod for the precise leveling instrument and it is quite intense work. Though total station trigonometric leveling can be accurate to a millimeter, it is not often applied in engineering. In order to improve the efficiency of crown settlement monitoring in tunnels, non-contact measurement using a smart tunnel laser convergence gauge to monitor tunnel crown settlement is proposed, and the monitoring steps are briefly introduced in this paper. Through theory analysis, the repeated monitoring and measuring tests both in the laboratory and onsite indicate that the precision of crown settlement monitoring using the smart tunnel laser convergence gauge can reach 0.70 mm. Compared with results from a DS05 percussive leveling instrument and a Leica TS15 total station on the construction sites of a cavern project in the Qindao and the Dangjinshan tunnel on the Dunge railway, the monitoring accuracy and stability of the smart tunnel laser convergence gauge are verified. The application prospects are vast using the smart tunnel laser convergence gauge to measure and monitor tunnel crown settlement thanks to its reliable precision, high efficiency, minimized construction disturbance and ability to simultaneously monitor peripheral convergence.
.Principles and Application of a Smart Tunnel Laser Convergence Gauge for Monitoring Tunnel Crown Settlement[J] MODERN TUNNELLING TECHNOLOGY, 2018,V55(2): 20-27
2018, Vol. 55 