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为研究极端波浪荷载作用下近海桥梁下方密实海床的瞬态液化稳定性,通过求解RANS方程和Biot方程,建立了极端波浪作用下箱梁下方密实海床动力响应的有限元数值模型。将该模型与以往试验结果对比,验证了该模型的准确性,基于此模型进一步研究了极端波浪作用下箱梁周围的波浪压力场分布及波浪特性、淹没深度对桥梁下方密实海床瞬态液化稳定性的影响。研究结果表明:处于淹没状态的箱梁对周围波压场影响较大,箱梁迎浪侧密实海床的瞬态液化深度大于背浪侧,液化深度幅值距离箱梁1/10~1/8波长范围内达到最大;随着波高与波浪周期的增大,箱梁左、右两侧密实海床瞬态液化深度均增大;在迎浪侧,当箱梁刚好完全被淹没时,海床瞬态液化深度最大,而在背浪侧,随着淹没深度增加,箱梁下方海床趋于安全。其研究结果可为跨海桥梁安全性分析提供参考。
In order to study the transient liquefaction stability of the tight seabed below the offshore bridge under the action of extreme wave loads, a finite element numerical model of the dynamic response of the tight seabed below the box girder under the action of extreme waves is established by solving the RANS equation and the Biot equation. The accuracy of this model is verified by comparing this model with the previous ones. Based on this model, the wave pressure distribution and wave characteristics around the box girder under extreme wave are further studied. The transient submergence of the submerged sea bed beneath the bridge The impact of stability. The results show that the submerged box girder has a great influence on the surrounding wave pressure field, and the transient liquefaction depth of the seafloor tight seafloor in the box girder is greater than that on the backwash side. The liquefaction depth amplitude is from 1/10 to 1/8 wavelength With the increase of wave height and wave period, the transient liquefaction depth of the dense seabed on the left and right sides of the box girder increases. On the wave-facing side, when the box girder is completely submerged, the seabed moment The liquefaction depth is the largest, while on the dorsal side, the seabed below the box girder tends to be safe as the inundation depth increases. The research results can provide a reference for the safety analysis of cross-sea bridges.