Assessment of stress relief during excavation on the seismic tunnel response by the pseudo-static method

作者：Sun, Qiang Qiang; Dias, Daniel^*

来源：Soil Dynamics and Earthquake Engineering, 2019, 117: 384-397.

DOI：10.1016/j.soildyn.2018.09.019

• Tunnels
• Seismic analyses
• Stress relaxation coefficient
• Soil-tunnel interaction
• Pseudo-static method

Pseudo-static analyses are performed to investigate the seismic response of circular tunnel considering the induced stress relief in the surrounding soil due to excavation. A set of two-dimensional plane-strain models of tunnels embedded in a single-layer thy soil are simulated. First, sensitivity analyses are performed for determining the dimensions of the model to avoid boundary effects. Then, the effects of Young's modulus of soil and the coefficients of earth pressure at rest on the numerical predictions are discussed. The pseudo-static predictions are compared to the closed-form solutions in order to validate their accuracy. The validated pseudo-static models are used to highlight the influence of the stress relief process during tunnel excavation on the tunnel's seismic behavior in conjunction with the convergence-confinement method. Parametric analyses are performed to examine the effect of soil-tunnel interface conditions, Yong's modulus of soil, the coefficient of earth pressure at rest, the magnitude of applied soil shear strains and the soil constitutive models. The pseudo-static analyses illustrate that the stress redistribution caused by the tunneling process has an important effect on the seismic forces in the lining. This influence is more evident at large stress relaxation coefficients (lambda). The stress relief process results in a significant increase of the axial forces particularly for the full-slip case. However, the stress relief has a minor effect on the bending moments. The additional lining force induced by the tunneling-induced stress relief should be adequately taken into consideration in current practice.

• 出版日期2019-2
• 单位合肥工业大学