考虑轴力和剪切效应的盾构隧道纵向变形分析

采用傅立叶级数法研究了不同荷载作用下轴力和剪切效应对盾构隧道变形的影响.?计及剪切变形所产生的地基反力,建立了弯曲变形的控制微分方程,推导了剪切变形的计算公式;采用与既有理论解对比的方法,验证了级数解的正确性;通过对比计算,分析了截面形式、端承条件、荷载形式、长高比以及有无弹性地基对盾构隧道剪切变形的影响,剪切刚度对弯...

Analysis of Longitudinal Deformation of Shield Tunnel Structures with Consideration of Axial Force and Shear Effect

The influence of axial force and shear effect on the longitudinal deformation of shield tunnel structures under different loads is investigated by Fourier series method. Taking into account the foundation reaction caused by shear deformation, the governing differential equation of bending deformation is derived, and a formula is proposed to calculate the shear deformation. The correctness of the Fourier series solution is verified by comparison with analytical solutions. Through comparative calculation, the main work is focused on addressing the influence of cross section, end support, type of load, ratio of length to height, and elastic foundation on the shear deformation of shield tunnel, the influence of shear rigidity on bending deformation, shear deformation and internal forces, and the influence of axial load exerted by installation of segment rings on bending deformation and bending moment. Results show that the shear deformation of shield tunnel accounts for more than 20% of the total deformation, which is caused by the form of annular section and low shear rigidity of shield tunnel. When shear deformation is counted, the whole deformation gets larger, but the bending deformation and bending moment are smaller than those without consideration of shear deformation. As shear rigidity decreases, shear deformation increases, and its proportion to the entire deformation also increases. In our case studies, when the shear rigidity decreases from 8×106 to 1×106 kN, the whole deformation goes up by 15.7%; the bending deformation and bending moment go down by 11.7% and 17.1%, respectively; the shear deformation increases 5.77 times; and the percentage of shear deformation to the whole deformation increases from 4.64% to 27.17%. Besides, the bending deformation and bending moment are also increased by installation-caused axial load, but the influence range is limited, often less than 2% in deflection and less than 3% in bending moment.