Structure Strengthening Method for Enhancing Seismic Behavior of Soft Tunnel Portal Section

Figure 1

Seismic damage of soft rock tunnel portal in Wencchuan Earthquake. (a) Staggered lining in Baiyunding Tunnel. (b) Lining cracking of Baiyunding Tunnel. (c) Inclined cracking and water seepage of lining in Ma’anshi Tunnel. (d) Lining spalling and block dropping in Youyi Tunnel.

(a)

(b)

(c)

(d)