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Abstract Considering the sequence of two-tunnel excavation，converting the underground space of tunnel to the case of elastic half-space under plane strain，an analytical solution is presented for stress and displacement of twin- tunnels with arbitrarily shape and size using analytic continuation method and Schwarz alternating method in an elastic half-plane. Because the depth is larger than the size of the tunnel，thus the effect of gravity gradient is ignored，and gravity loads are simplified as uniform normal loads along far-field boundary. As a special case，a close solution for stress and displacement field around circular twin-tunnels at great depth considering the influences of lining forces of tunnels is given. Circular twin-tunnels are subjected to uniform internal pressure and their construction sequences are properly taken into consideration. Comparison between the results of numerical analysis by two-dimensional finite element method and those from the closed solutions indicates that the closed solution is reliable and applicable for the stress and displacement field around the twin-tunnels at great depth.
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Received: 10 June 2011
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2012, Vol. 31 
