Located in the north of Changsha City, China, the Guanyinyan Tunnel Project is an important passage to connect expressway with urban roads. It is a single feasible route for tunneling to avoid soil disturbance caused by tunnel construction on Xixin Buddhist Temple and surrounding complex buildings.

Restricted by narrow space, the application of conventional roadbed, double-arch tunnels and split tunnels either fails to meet transport demand or environmental protection. In this project, an innovation proposal of unequal-span four-arch tunnel with two-way ten-lane is put forward. Of ten lanes, 6 lanes in the middle lead to expressway, and 4 lanes serve as urban road on both sides.