Yun Lang

Suction embedded plate anchors are widely used in deepwater mooring systems, which can withstand significant vertical loading. During the installation, the mooring chain is tensioned and causes the anchor to rotate, which is known as keying. With a large deformation finite element approach of the coupled Eulerian–Lagrangian method, the chain effects are incorporated into the keying of suction embedded plate anchors. The effectiveness of the proposed method is verified by numerical results and centrifuge tests. The numerical study reveals that the installation angle of the chain has a significant effect on the loss of embedment, especially combined with the effects of load eccentricity and soil strength. The losses of embedment are 0.024~0.273 and 0.217~1.755 anchor width for the installation angles of 15° and 90°, respectively. The ultimate bearing capacity factor decreases with the increasing of load eccentricity and soil strength, because a cavity is formed at the anchor back. Empirical formulae are finally developed for engineers to rapidly estimate the embedment loss and ultimate pullout capacity of suction embedded plate anchors.

Reservoirs often suffer from water blooms, which are likely related to the hydrodynamic and water temperature characteristics of the tributary bays. To obtain the detailed changing process of hydrodynamics and water temperature stratification, it is necessary to choose a suitable vertical coordinate system in order to achieve the required precision. Based on a physical model experiment of cold water flowing into the Generalized Reservoir Hydraulics (GRH) flume, both the σ-coordinate system model and the z-coordinate system model are built for comparison. For the z-coordinate system model, the influences of different grid resolutions and different bottom slopes on the simulation accuracy are also analyzed. The results show that the σ-coordinate system model can simulate cold-water underflow in a reservoir better than the z-coordinate system model, and the numerical errors of the z-coordinate system model can be reduced but not eliminated by increasing the horizontal grid resolution. When the bottom slope of the reservoir is less than 18‰, the z-coordinate system model can also be used to simulate cold-water underflow in a reservoir. The conclusions about vertical coordinate systems can be applied to the development of a three-dimensional hydrodynamic and water temperature model of reservoirs.

After the impoundment of the Three Gorges Reservoir (TGR) in China, water environment problems induced by water temperature stratification in the Xiangxi Bay (XXB, a typical tributary bay of TGR) received wide attention. In this study, a 3‐dimensional (3D) hydrodynamic and water temperature coupled model with the z‐coordinate in the vertical direction was established with Delft3D software to simulate the continuous hydrodynamic and water temperature process of XXB in 2009, and the static stability and mixing depth were also analyzed. The results show that the upstream inflow is prevented from entering TGR with nutrients enriching and mixing in the upper and middle reach of XXB from winter to early spring, which is the primary cause of spring algal blooms in XXB. Therefore, measures such as improving the upstream hydrodynamic conditions and forcing the nutrients to flow into TGR in winter should be more effective in alleviating spring algal blooms than the artificial tide operation of TGR proposed by previous studies.