Measurement and analysis on EPB shield machine tunneling efficiency in#br#
Jinan composite stratum
Men Yanqing1,2 Wang Yongjun1 Zhou Jianguo1 Liao Shaoming2,3 Zhang Kun1
1. Jinan Rail Transit Group Co., Ltd., Jinan 250101, China; 2. College of Civil Engineering, Tongji University, Shanghai 200092, China;
3. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China
Abstract：Based on the earth pressure balanced (EPB) shield tunneling practice of Jinan metro line 1, an evaluation method of tunneling efficiency was proposed by combining the respective power dissipation index and construction parameter dispersion index under the rated configurations of shield machine. Furthermore, by applying the evaluation method, the following varying characteristics of tunneling efficiency, including cutting of cutterhead, advancing of shield and soil conveying of screw machine, were obtained. The results show that the total tunneling power of shield machine changes from 400kW in loess-silty composite stratum to 1250kW in silty-cobble composite stratum. The cutting of cutterhead and advancing of shield machine account for 66%-84% of the total energy consumption of shield tunneling. The cutting torque and rotating speed of cutterhead have obvious accumulation characteristics, but the advancing speed and thrust force distribution of shield machine have less accumulation characteristics than cutterhead parameters. However, the rotating speed and torque of screw machine have unobvious distinction in different stratums. Furthermore, there is no necessary correlation between respective power dissipation and parameter dispersion index. In some exceptional cases, it could be difficult to control a shield machine although the energy consumption during tunneling is less, which shall be carefully considered in the selection of shield types and construction process.
