ZHANG Zhi-guo, LI Sheng-nan, ZHANG Cheng-ping, et al. Analysis of stratum deformation and lining response induced by shield construction considering influences of underground water level rise and fall[J]. 2019, 40(S1): 281-296.
DOI:
ZHANG Zhi-guo, LI Sheng-nan, ZHANG Cheng-ping, et al. Analysis of stratum deformation and lining response induced by shield construction considering influences of underground water level rise and fall[J]. 2019, 40(S1): 281-296.DOI: 10.16285/j.rsm.2018.1808.
Analysis of stratum deformation and lining response induced by shield construction considering influences of underground water level rise and fall
A high risk will be raised when the groundwater level changes dramatically during the construction of shield tunnel. However
the impact of fluctuation of groundwater table is seldom considered in the construction of shield excavation in current studies. Besides
the deformation and stress analysis of tunnel lining are paid even less attention. The non-uniform convergence deformation at the periphery of the tunnel cavity is introduced into this paper
considering the fluctuation of groundwater level when the shield tunnel is being constructed. The complex functions are applied in calculating the deformation of ground and lining and stress caused by shield tunnel excavation under the influence of the variation in groundwater table. The presented method is proved to be reliable by comparing the theoretical analysis results with the numerical simulation results. In addition
sensitivity analysis of parameters such as the groundwater level depth
thickness of lining
radius of tunnel is carried out. The results show that the radial displacement of the lining presents a stem-upwards "apple" shape. When the groundwater level decreases
the radial displacement gradually transforms from "duck egg" shape to "apple" shape that tends to be more and more obvious. Thecircumferential displacement of the lining likes an inclined "apple". With a decline of groundwater level
the range of the oblique "apple" expands. Under the influence of lining thickness
tunnel radius etc.
the distribution of radial stress shows the same variation rules as mentioned above. With the increase in these two parameters
the distribution of radial stress gradually changes from the horizontal “duck egg” to “ ” shape. As the groundwater level drops
the shape of radial stress shrinks towards the center. The circumferential stress of the lining decreases slightly with an increase in thickness of the lining. While it decreases obviously with an increase in the tunnel radius. As the groundwater level drops
the distribution of circumferential stress gradually changes from the vertically placed "duck egg" shape to the "8" shape. The tangential stress of the lining shows the same variation rules under the influence of lining thickness and the tunnel radius. The distribution of tangential stress shows a stem-downwards "apple" shape. The research results can give a reference to the shield construction when the groundwater level changes obviously.