Abstract:

The main geological characteristics of Baozhen Tunnel are high ground stress, bedded strata asymmetrical load and large deformation of tunnel in soft rock. Based on the study of the tunnel construction technology in soft rock with high ground stress both in China and foreign countries, the author makes analysis on mechanical behavior of tunnels in asymmetricalloaded stratum and asymmetricalloaded and highly stressed strata respectively. Then, the author presents the composite construction principle of advance support, enhanced primary support, reasonable deformation, proper stress releasing before stress resisting, flexible support installed before rigid support, timely closing the support structure, strengthening tunnel invert, optimizing tunnel structure and geological predication. The excavation method, ventilation method, equipments matching technology and management technology adopted has ensured the safe and rapid construction of the tunnel.

Key words:  high ground stressbedded strata asymmetrical loadlarge deformation of tunnel in soft rock, tunnelrapid construction technology