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A Field Test Study on the Large Deformation Control for Tunnels Built in Seriously-weathered Carbonaceous Slate Strata with High Geostress
(1. School of Civil Engineering, North China University of Technology, Beijing 100144; 2. China Railway City Development and Investment Group Co., Ltd., Chengdu 610218)
Abstract In view of the various problems caused by seriously weathered carbonaceous slate strata with high geo? stress, such as the development of joints and fractures, the fracture of the surrounding rock, and prominent large deformation hazards during the tunnelling process, this paper carries out a field test study on the advanced control measures for surrounding rock stress. The results show that conventional support measures cannot effectively solve the large deformation problem encountered by tunnels built in seriously-weathered carbonaceous slate with high geostress, and the use of advanced control measures for geostresses can effectively reduce the surrounding rock deformation of a tunnel while reducing the stress in the tunnel steel frame and surrounding rock. In contrast to the control section using conventional measures, the final values of horizontal convergence in the advanced borehole and pilot tunnel test sections are 152.93 mm and 149.22 mm, respectively, with a decrease of 27.95% and 29.70%; the final values of the crown settlement are 24 mm and 15 mm respectively, with a decrease of 61.29% and 75.81%; the maximum values of the steel frame stress are - 143 MPa and -157 MPa, respectively, with a decrease of 23.12% and 20.28%; and the maximum values of the surrounding rock stress are 0.379 MPa and 0.406 MPa, respectively, with a decrease of 77.44% and 75.84%.
Abstract：
In view of the various problems caused by seriously weathered carbonaceous slate strata with high geo? stress, such as the development of joints and fractures, the fracture of the surrounding rock, and prominent large deformation hazards during the tunnelling process, this paper carries out a field test study on the advanced control measures for surrounding rock stress. The results show that conventional support measures cannot effectively solve the large deformation problem encountered by tunnels built in seriously-weathered carbonaceous slate with high geostress, and the use of advanced control measures for geostresses can effectively reduce the surrounding rock deformation of a tunnel while reducing the stress in the tunnel steel frame and surrounding rock. In contrast to the control section using conventional measures, the final values of horizontal convergence in the advanced borehole and pilot tunnel test sections are 152.93 mm and 149.22 mm, respectively, with a decrease of 27.95% and 29.70%; the final values of the crown settlement are 24 mm and 15 mm respectively, with a decrease of 61.29% and 75.81%; the maximum values of the steel frame stress are - 143 MPa and -157 MPa, respectively, with a decrease of 23.12% and 20.28%; and the maximum values of the surrounding rock stress are 0.379 MPa and 0.406 MPa, respectively, with a decrease of 77.44% and 75.84%.
CUI Guangyao1 WEI Hanghang1 WANG Mingsheng2
.A Field Test Study on the Large Deformation Control for Tunnels Built in Seriously-weathered Carbonaceous Slate Strata with High Geostress[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(3): 183-189
2022, Vol. 59 