Effects of adjacent paleochannel sedimentary on the seismic response of structure with incident SH-wave

Abstract

This paper combines the indirect boundary element method and the idea of “region-matching technique” to study the impact of adjacent paleochannel on structures in a layered half-space with incident SH-wave. It decomposes the model into paleochannel closed region, layered half-space open region, and rigid foundation-elastic structure. Wave field in the closed region only have scattered wave, and wave field in the open region includes scattered and free field. The scattered and free field are simulated by the dynamic Green's function and the direct stiffness method, respectively. Then, response of soil-structure system is solved by employing the boundary continuity conditions and dynamic equilibrium of structure. After verification of the method, seismic response of structure under the influence of adjacent paleochannel shape, distance between the paleochannel and structure, and shear wave velocity ratio of the paleochannel were analyzed. Results show: All three paleochannel shapes (ellipse, trapezoid, triangle) are adverse to the structure compared to the case of no paleochannel, and ellipse is the most unfavorable shape; Effect of paleochannel should be taken into account when paleochannel distance L/a<100; Higher shear wave velocity ratios result in larger peak of structural displacement; Structural response is more amplified in oblique incidence than vertical incidence.