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The Impact of Spatial Variability of Soils on Shield Tunnelling
(1. Department of Civil and Engineering, Shanxi Institute of Technology, Yangquan 045000; 2. College of Civil Engineering, Tongji University, Shanghai 200092)
Abstract To investigate the impact of spatial variability of soil strength parameters on the ground surface deforma? tion caused by shield tunnelling, the cohesion and internal friction angle are selected as the random variables, the random fields are discretized through the Karhunen-Loève expansion method, the soil parameters random fields are mapped respectively to FLAC 3D model elements by using the Matlab software, and analytical calculations are performed by using FLAC 3D software. The results show that the spatial variability of the soil strength parameters has a significant impact on ground surface deformation. Specifically, the impact of the scale of fluctuation in vertical direction is greater than that of the scale of fluctuation in horizontal direction, and the horizontal displacement of the ground surface is more affected than the ground surface settlement. Furthermore, when the scale of fluctuation in ver? tical direction is less than 1 times the tunnel diameter, the values of ground settlement obtained from multiple simulations conform to a normal distribution, allowing to estimate the exceeding probability or the specified limit of the ground surface settlement by deterministic analysis method.
Abstract：
To investigate the impact of spatial variability of soil strength parameters on the ground surface deforma? tion caused by shield tunnelling, the cohesion and internal friction angle are selected as the random variables, the random fields are discretized through the Karhunen-Loève expansion method, the soil parameters random fields are mapped respectively to FLAC 3D model elements by using the Matlab software, and analytical calculations are performed by using FLAC 3D software. The results show that the spatial variability of the soil strength parameters has a significant impact on ground surface deformation. Specifically, the impact of the scale of fluctuation in vertical direction is greater than that of the scale of fluctuation in horizontal direction, and the horizontal displacement of the ground surface is more affected than the ground surface settlement. Furthermore, when the scale of fluctuation in ver? tical direction is less than 1 times the tunnel diameter, the values of ground settlement obtained from multiple simulations conform to a normal distribution, allowing to estimate the exceeding probability or the specified limit of the ground surface settlement by deterministic analysis method.
JIN Xuemei1,
2 HUANG Hongwei2 ZHANG Dongming2
.The Impact of Spatial Variability of Soils on Shield Tunnelling[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(2): 62-70
2022, Vol. 59 