STUDY OF TUNNEL-SOIL INTERACTION INDUCED BY TUNNELING UNDERLYING

Based on the condition of tunnel deformation caused by tunneling underlying, a theoretical solution is obtained to calculate the response of existing tunnels. The additional loading upon existing tunnel caused by tunneling underlying can be calculated by modified Gaussian formula. By treating the existing tunnel as Euler-Bernoulli beam lying on Kerr foundation model, the strain and stress response of the overlying tunnel can be obtained by considering the case of freedom at both ends of tunnel. Cases studies show that the solutions of the proposed method have better agreement with the centrifuge data than the existing centrifuge tests. Compared with existing theory and degraded Pasternak foundation model solution, the prediction of the proposed method is close to the measured data. Further study shows that the tunnel displacement decreases with the increment of the skew angle between two tunnels, but the tunnel bending moment increases. The displacement and bending moment of the tunnel increase approximately linearly with the volume loss. Displacement and bending moment of the tunnel decrease as the depth of new tunnel increases.