A new tunnelling crossing above with a small clearance will induce uplift of the underlying shield tunnel.Thus,predicting the existing shield tunnel displacement is very significant to above-crossing tunnel-ling construction control and the protection of the existing tunnel.The analytical solution for the displace-ment of the existing shield tunnel due to above-crossing tunnelling is proposed based on the two-stage anal-ysis method.The existing shield tunnel was simulated by the non-continuous shield tunnel model which can weaken circumferential joint.The Riftin foundation model was adopted to consider the shield tunnel-ground interaction.The unloading stressing induced by new tunnel excavation was obtained by Mindlin classic so-lution,which was then imposed on the shield tunnel to establish analytical solution of the longitudinal de-formation of the existing shield tunnel subjected to the construction of new tunnel above.The predictions by the proposed method were compared with field measurements and the calculation results by Euler-Ber-noulli(EB)equivalent continuous beam model from Hangzhou jacking tunnel above-crossing Metro Line 1 and Shanghai Metro Line 8 crossing over Metro Line 1 to verify the feasibility of the proposed method.It shows that the tunnel displacements predicted by the proposed method and the EB continuous beam model are both close to the measured results.The bending moments and joint openings of the existing shield tun-nel predicted from the proposed method are larger than those from the EB continuous beam model.Howev-er,the displacement curves predicted by the EB continuous beam model are smooth and continuous,while the displacement curves predicted by the proposed method are composed of a series of short straight lines,and significant sharp points appear in the joints.
关键词
隧道上穿/既有盾构隧道/环间接头弱化/纵向变形/非连续盾构隧道模型/Riftin地基模型
Key words
above-crossing tunnelling/existing shield tunnel/weakening of circumferential joint/longitudi-nal deformation/non-continuous shield tunnel model/Riftin foundation model
维普
万方数据