Abstract The principal stresses that occur in soil below ground level often change direction due to engineering activities. A typical example would be the cyclic loading applied by waves and currents onto the foundation of offshore structures. Even though the principal stress rotations (PSR) are recognized as some kind of “loading” that is exerted onto seabed soil, it is ignored in most investigations into how soil around marine structures responds to ocean waves and currents. In response this paper will simulate the fluid-seabed-structure interactions (FSSI) while considering the impact of PSR. This simulation will utilize an integrated numerical model in which VARANS equations are used for the flow motion. A coupled fluid-dynamic framework and a generalized plasticity model will be developed for the saturated porous medium to examine the cyclic loading of seabed and the continuous rotation of principal stress orientations. It is predicted that the stress path in the τ x z versus ( σ x ′ − σ z ′ ) plane around the structure will denote variations in deviator stress in conjunction with the rotations of the principal stress axis. The mechanical impact of PSR becomes most significant in the region beneath the breakwater and up to a depth of the half thickness of the seabed. Ignoring the PSR-induced deformation may lead to an underestimation of ( p P S R − p n o − P S R ) ∕ γ w d by 35% in this region.

中文翻译：

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考虑主应力轴旋转影响的流体-海床-结构相互作用的数值模拟

摘要 地表以下土壤中的主应力经常因工程活动而改变方向。一个典型的例子是波浪和水流施加到海上结构基础上的循环载荷。尽管主应力旋转 (PSR) 被认为是施加到海床土壤上的某种“载荷”，但在大多数关于海洋结构周围土壤如何响应海浪和洋流的调查中，它被忽略了。作为回应，本文将模拟流体-海底-结构相互作用 (FSSI)，同时考虑 PSR 的影响。该模拟将利用一个集成的数值模型，其中 VARANS 方程用于流动运动。将为饱和多孔介质开发耦合流体动力学框架和广义塑性模型，以检查海床的循环载荷和主应力方向的连续旋转。预计 τ xz 与结构周围 (σ x ′ - σ z ′ ) 平面中的应力路径将表示偏应力随主应力轴旋转的变化。PSR 的机械影响在防波堤下方的区域和海床厚度的一半以下区域变得最显着。忽略 PSR 引起的变形可能会导致在该区域低估 (p PSR − pno − PSR ) ∕ γ wd 35%。预计 τ xz 与结构周围 (σ x ′ - σ z ′ ) 平面中的应力路径将表示偏应力随主应力轴旋转的变化。PSR 的机械影响在防波堤下方的区域和海床厚度的一半以下区域变得最显着。忽略 PSR 引起的变形可能会导致在该区域低估 (p PSR − pno − PSR ) ∕ γ wd 35%。预计 τ xz 与结构周围 (σ x ′ - σ z ′ ) 平面中的应力路径将表示偏应力随主应力轴旋转的变化。PSR 的机械影响在防波堤下方的区域和海床厚度的一半以下区域变得最显着。忽略 PSR 引起的变形可能会导致在该区域低估 (p PSR − pno − PSR ) ∕ γ wd 35%。