Abstract:

Extremely complex terrains, i.e. rock bulge of tunnel roof, high and vertical rockface under tunnel roof, and asymmetricallypressured steep and high terrain on tunnel roof, are encountered during construction of Pingqiao #1 Tunnel portal on Menghua Railway; the Yingpanshan Bridge is connected to the tunnel portal; a series of problems, i.e. interaction between bridge abutment and tunnel portal structure, slope protection and tunnel portal breakthrough and layout of construction fields, exist in design. Hence, the terrain of construction site and geological conditions are investigated; comparing analyses are made for advantages and disadvantages of both integral mode and separation mode of bridgetunnel connection; the integral bridgetunnel connection mode is adopted; a design scheme for asymmetrical structure is proposed for asymmetricallypressured steep and high terrain to protect the slope; the problems of tunnel portal breakthrough and layout of construction fields have been solved by connecting constructed bridge with temporary bailey beam bridge.

Key words: bridgetunnel connection section, tunnel portal, integral mode, separation mode, slope protection, sandstone