关键词: 地下工程, 盾构隧道, 数值分析, 模型试验, 传感器

Abstract: The seismic responses of metro shield tunnel in soft soil area were analyzed by using finite-infinite element coupled analysis model. The acceleration responses, the displacement responses and the law of dynamic strain of soil-metro shield tunnel system were studied. According to the influential factors and characteristics of soil-metro structure’s seismic responses, the layout principle of sensors was summarized, which defined the location of the observation section and the main observation indexes of shield tunnel structure in shaking table test. Results unveiled that the high-frequency component of seismic waves were filtered and the low-frequency component were amplified by foundation soil. The acceleration amplification factor of foundation was related with buried depth and seismic waveform. The maximal seismic stress responses of tunnel structure were located in an angle of 30° to the top and the bottom of tunnel which can be considered as the key points of strain measurement. The acceleration responses and dynamic pressures between structure and soil varied with height, hence the dynamic differences and variations of each point can be measured by arranging sensors at different heights of the structure. At the end of the structure, the end restraint effect on observation section 0.26D(D represents the structure width) away from the end of the structure reached 13.58%, which is about 3 times that 1D from the end. Therefore, the main and auxiliary observation sections should be at least 1D away from the end of the structure. The proposed measurement scheme in this paper guaranteed the data collection in shaking table test of metro shield tunnel and provided a reference for other model tests of underground structures.

Key words: underground engineering, shield tunnel, numerical analysis, shaking table test, sensors