Three-dimensional (3D) confined wall jets have various engineering applications related to efficient energy dissipation. This paper presents experimental measurements of mean flow development for a 3D rectangular wall jet confined by a vertical baffle with a fixed distance (400 mm) from its surface to the nozzle. Experiments were performed at three different Reynolds numbers of 8333, 10,000 and 11,666 based on jet exit velocity and square root of jet exit area (named as B), with water depth of 100 mm. Detailed measurements of current jet were taken using a particle image velocimetry technique. The results indicate that the confined jet seems to behave like an undisturbed jet until 16B downstream. Beyond this position, however, the mean flow development starts to be gradually affected by the baffle confinement. The baffle increases the decay and spreading of the mean flow from 16B to 23B. The decay rate of 1.11 as well as vertical and lateral growth rates of 0.04 and 0.19, respectively, were obtained for the present study, and also fell well within the range of values which correspond to the results in the radial decay region for the unconfined case. In addition, the measurements of the velocity profiles, spreading rates and velocity decay were also found to be independent of Reynolds number. Therefore, the flow field in this region appears to have fully developed at least 4B earlier than the unconfined case. Further downstream (after 23B), the confinement becomes more pronounced. The vertical spreading of current jet shows a distinct increase, while the lateral growth was found to be decreased significantly. It can be also observed that the maximum mean velocity decreases sharply close to the baffle.

In order to further reveal the failure mode and dynamic response law of dangerous rocks with different degree of weathering in the rock cavity under the action of earthquake and to provide early warning and forecast for steep slope of dangerous rocks in similar earthquake areas, a typical steep slope of dangerous rock in earthquake area of Sichuan, China, was taken as the research object, after detailed geological survey, and according to the chain development law of dangerous rock, the steep slope of dangerous rock before the earthquake was restored. Based on the 3D particle flow software PFC3D, the dangerous rock was divided into 3 modes according to the degree of weathering of the mudstone rock cavity, and the three‐dimensional discrete element dangerous rock model under different modes was established. By introducing the horizontal and vertical two‐way coupled seismic waves in Wenchuan, Sichuan, in 2008, the failure evolution process of steep slope of dangerous rock under the action of the horizontal and vertical coupled seismic waves was dynamically simulated, which proved the rationality of the simulation. The frequency spectrum of velocity‐time history signal of each rock block in the dangerous rock model was analyzed by MATLAB programming, and the time‐frequency characteristics of each dangerous rock model under the action of coupled seismic wave were studied. The research results have important scientific guiding significance and practical value for the dynamic stability evaluation and prediction of such steep slope of dangerous rocks under the combined action of rock cavity weathering and earthquake.

In the densely populated urban environment, ground movements induced by deep excavations inevitably present a risk of damage to adjacent buildings and structures. An important and necessary aspect to justify the engineering design is to evaluate the degree of risk of such damage. This paper presents a specific procedure to evaluate the engineering design by assessing the risk level of building damage based on the deformation profiles along the ground surface which are calculated via numerical modelling and verified by empirical methods. This procedure is afterwards applied to justify the engineering design of the extension line construction of a metro project between PK0 + 344.00 and PK0 + 407.00 with the cut‐and‐cover excavation method. The results demonstrate that the damage risk levels of all the buildings adjacent to the excavations are within category level 0 indicating that the relevant design is acceptable while considering the risk of building damage induced by deep excavations.

Multiporous turbulent wall jet is an important and interesting flow phenomenon in the water‐filling process of ship locks. Its fluid flow characteristics have become the essential reason of various poor hydraulic conditions, significantly affecting the safety of chamber structures and mooring ships. Due to the coupling interaction of different boundaries in chambers, current related studies have led to few reports on multiporous turbulent wall jets with opposite arrangements in the literature. This paper systematically reviews, in condensed form, the mean and turbulence characteristics of a three‐dimensional (3D) wall jet and a multiporous wall jet with tandem and opposite arrays, respectively. The contents consist of a necessarily brief overview of a 3D wall jet theory and previous experimental and numerical findings of three types of wall jets. The results show that the particle image velocimetry (PIV) measuring technique and large eddy simulation (LES) numerical method appear as owning greater potential for studying multiporous turbulent wall jet in the future. In addition, the issues concerned with flow characteristics of multiporous wall jets generating from opposite holes that need more attention are also discussed, including flow partition structure, key factors, and proper ideas. This study would provide some feasible directions to explain the flow mechanism of multiporous turbulent wall jets.

A three-dimensional wall jet in a confined space is a ubiquitous flow occurrence in important engineering domains. Previous studies have not fully explained its turbulence characteristics. In this paper, a particle image velocimetry measuring technique was used to observe a rectangular three-dimensional confined wall jet. The objective of this study is to investigate specially turbulence statistics in regions affected by the vertical wall (16 ≤ x/d < 27), and the effect of the Reynolds numbers and submerged depths on that. The results show that profiles of turbulence statistics are not similar in the region 16 ≤ x/d < 19. Turbulence characteristics in the region 19 ≤ x/d < 24 correspond to those of the radial decay region due to the influence of the vertical wall, where both the mean and fluctuating motions are completely developed in advance. In the region 24 ≤ x/d < 27, profiles of turbulence statistics in two planes collapse rather poorly. Peak values of turbulence quantities in the lateral plane show a positive correlation with Reynolds numbers obviously, while the similar trend is not presented in the symmetry plane. Furthermore, in the region 24 ≤ x/d < 27, profiles of turbulence intensities are little sensitive to small variations in submerged depths. However, peak values of Reynolds shear stresses show a positive correlation. This study can promote the understanding of turbulence characteristics of a three-dimensional confined wall jet.