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Numerical Simulation Study on the Deformation and Failure Mechanism of Tunnel Surrounding Rock under the Effect of Water-rich Sand Layer
(1 School of Civil Engineering, Shandong Jianzhu University, Jinan 250101; 2 Jinan Rail Transit Group Co., Ltd, Jinan 250100;3 Shandong Institute of Geological Scences, Jinan 250013; 4 Shandong Provincial Academy of Building Research, Jinan, Shandong,250031)
Abstract In order to study the deformation and failure mechanism of tunnel surrounding rock under the effect of
water-rich sand layer, taking a running tunnel of metro line M2 in certain city as the background, the effect of five factors of thickness of the sand layer, thickness of the water-resisting layer, underground water level and cohesion and frictional angle of water-resisting layer is considered. Twenty five comparison schemes are designed, a systematic numerical simulation and comparison are carried out, the influence law of different factors on the deformation and failure mechanism of surrounding rock and the sensitivity degree of each factor are obtained, and the corresponding engineering measures are given as well. The results show that the crown is the key part of surrounding rock deformation and failure in tunnels subjected to the effect of water-rich sand layer; the deformation and area of plastic zone of surrounding rock at crown decreases with the increase of the thicknesses of water-resisting layer, cohesion and internal friction angle, while the deformation and area of plastic zone of surrounding rock at crown keeps increasing
with the increase of thickness of the sand layer or underground water level; the thickness of the water-resisting layer and cohesion are the significant factors that affect the deformation and failure of surrounding rock under such conditions, adequate safety thickness of water-resisting layer at crown should be guaranteed as for the design of tunnel alignment and grouting reinforcement of water-resisting layer can be taken to improve the stability of tunnel surrounding rock.
Abstract：
In order to study the deformation and failure mechanism of tunnel surrounding rock under the effect of
water-rich sand layer, taking a running tunnel of metro line M2 in certain city as the background, the effect of five factors of thickness of the sand layer, thickness of the water-resisting layer, underground water level and cohesion and frictional angle of water-resisting layer is considered. Twenty five comparison schemes are designed, a systematic numerical simulation and comparison are carried out, the influence law of different factors on the deformation and failure mechanism of surrounding rock and the sensitivity degree of each factor are obtained, and the corresponding engineering measures are given as well. The results show that the crown is the key part of surrounding rock deformation and failure in tunnels subjected to the effect of water-rich sand layer; the deformation and area of plastic zone of surrounding rock at crown decreases with the increase of the thicknesses of water-resisting layer, cohesion and internal friction angle, while the deformation and area of plastic zone of surrounding rock at crown keeps increasing
with the increase of thickness of the sand layer or underground water level; the thickness of the water-resisting layer and cohesion are the significant factors that affect the deformation and failure of surrounding rock under such conditions, adequate safety thickness of water-resisting layer at crown should be guaranteed as for the design of tunnel alignment and grouting reinforcement of water-resisting layer can be taken to improve the stability of tunnel surrounding rock.
LIU Ping1 LIU Chi2 WANG Hongtao1 ZHANG Hongjun3 YANG Yong4 ZHANG Xin1 LIU Luyao1
.Numerical Simulation Study on the Deformation and Failure Mechanism of Tunnel Surrounding Rock under the Effect of Water-rich Sand Layer[J] MODERN TUNNELLING TECHNOLOGY, 2020,V57(4): 74-81
2020, Vol. 57 