Response characteristics and tensile failure evaluation of asphalt concrete core wall under spatial oblique incidence of P-wave

Abstract

The research on asphalt concrete core embankment dam under the spatial oblique incidence of seismic wave and the dynamic tensile failure of the core is still insufficient. This paper considers the spatial arbitrariness of P-wave incident azimuth angle γ and oblique incident angle α, constructs the non-uniform free field on the foundation boundary based on the wave field superposition principle, and establishes a wave input method for P-wave oblique-incidence in three-dimensional space. Then, an empirical formula for the change in the instantaneous tensile strength of asphalt concrete with the strain rate is established on the basis of the test results. Furthermore, a new core safety evaluation method based on instantaneous tensile stress and strength is proposed to discriminate element tensile failure. Finally, the influence law of incident azimuth and oblique incident angles on the acceleration and stress spatial distribution of asphalt concrete core is analyzed. The damage mechanism of the core caused by the surge of local tensile stress caused by spatial oblique incidence is revealed. The traditional static strength discrimination method has an error in discriminating the core failure compared with the method proposed in this paper. The distribution characteristics of tensile weak zone and failure zone of the core under different incident modes are clarified. Results show that compared with the vertical incident, the core accelerations in the water flow and dam axis directions increased by a maximum of 9.6 times and 68% under spatial oblique incidence (γ ∈ [0°, 90°] and α∈(0°, 75°]), and the core acceleration in the vertical direction can be reduced by 69%. The core compressive and tensile stresses increased by a maximum of 31.3% and 4.0 times under spatial oblique incidence (γ ∈ [0°, 90°] and α∈(0°, 75°]). Neglecting spatial oblique incidence will underestimate the core accelerations and stresses seriously. The more the incident direction deviates to the dam axis and the larger the oblique incident angle is, the more prone it is to tensile failure on the wave-facing side of the core. When the incident direction is consistent with the dam axis and the incident angle is 75°, the tensile failure on the wave-backing side of the core is more serious than that on the wave-facing side. The use of the traditional static strength discrimination method will result in the large crack failure error of the core.