Abstract: The authors investigate the deformation and mechanical characteristics of a landslide-tunnel orthogonal system by examining a highway tunnel that crosses a landslide. InSAR technology is utilized to measure slope surface deformation, which is validated against GNSS monitoring data. Numerical simulations are conducted to analyze the stress-strain response of the tunnel under landslide loading. A simplified calculation of surrounding rock pressure is performed using the transfer coefficient method, considering landslide thrust. The results reveal the following: (1) InSAR monitoring results are highly consistent with GNSS observations, with correlation coefficients all exceeding 0.96 at four monitoring points, confirming the reliability of InSAR in capturing large-scale landslide deformation. (2) Numerical simulations show that deformation is concentrated at the slope toe and rear, with a maximum displacement of 4.08 cm. Peak shear stress is observed around the tunnel sidewalls, where the right sidewall displacement reaches 2.06 cm, which is 0.47 cm greater than that of the left, and the crown experiences a vertical compressive stress peak of 2.74 MPa, indicating pronounced asymmetric loading and potential lining cracking. (3) The surrounding rock pressure exhibits a trapezoidal asymmetric distribution, with maximum values of 1.03 and 3.19 MPa at the sidewall and the crown on the landslide side, respectively, both significantly higher than those on the opposite side, resulting in structural stress imbalances. (4) Under orthogonal conditions, the asymmetric thrust of landslide creep can readily induce longitudinal cracks, sidewall tilting, and floor heave in the tunnel lining.

Key words: landslide-tunnel system, InSAR technology, numerical simulation, surrounding rock pressure, deformation