In this paper, a spatiotemporal framework is developed for identifying building vulnerabilities and content evacuations during riverine flooding events. This work investigates the spatiotemporal properties required to trigger building contents evacuations in the floodplain during a flood event. The spatial properties for building risks are based on topography, flood inundation, building location, building elevation, and road access to determine five categories of vulnerability, vulnerable basement, flooded basement, vulnerable first-floor, flooded first-floor, and road access. Using this framework, a model designed to track the spatiotemporal patterns of building evacuations is presented. The model is based upon real-time flood forecast predictions that are linked with building properties to create a model that captures the spatiotemporal ordering of building vulnerabilities and building content evacuations. Applicable to different communities at risk from flooding, the evacuation model is applied to a historical flood for a university campus, demonstrating how the defined elements are used to derive a pattern of vulnerability and evacuation for a campus threatened by severe flooding. 相似文献
This paper is primarily focused on why and how to consider the varied discharge capacity during simulations of consolidation via prefabricated vertical drains (PVDs) for soft soil deposits. First, the existing studies regarding discharge capacity are summarized and discussed. These studies conclude that the discharge capacity of PVDs at sites vary with the confining pressure and consolidation time. Next, a series of analytical solutions that consider the variation of discharge capacity with ground depth, consolidation time or both simultaneously are presented and compared. Applications of these solutions and of the newly introduced parameters are described. Then, a well-documented case history on ground treatment with PVDs is analyzed, in which the parameters related to the time-dependent discharge capacity were obtained from laboratory tests. A comparison between a classical solution and the newly presented method indicates that consideration of the varied discharge capacity in the consolidation theory can better predict the consolidation process of PVD-improved ground. 相似文献
Control parameter optimization is an efficient way to improve the endurance of underwater gliders (UGs), which influences their gliding efficiency and energy consumption. This paper analyzes the optimal matching between the net buoyancy and the pitching angle and proposes a segmented control strategy of Petrel-L. The optimization of this strategy is established based on the gliding range model of UG, which is solved based on the approximate model, and the variations of the optimal control parameters with the hotel load are obtained. The optimization results indicate that the segmented control strategy can significantly increase the gliding range when the optimal matching between the net buoyancy and the pitching angle is reached, and the increase rate is influenced by the hotel load. The gliding range of the underwater glider can be increased by 10.47% at a hotel load of 0.5 W. The optimal matching analysis adopted in this study can be applied to other UGs to realize endurance improvement.
The Jiashian earthquake (ML 6.4) occurred on 4 March 2010. It was the largest inland event in southern Taiwan of 2010. The mainshock location was unexpected since it occurred in an area with relatively low background seismicity. In addition, reports of earthquake focal mechanisms do not fit with any known active fault geometry. In order to understand the origin of this earthquake, especially its rupture process, we perform a joint source inversion by using teleseismic body wave, GPS coseismic displacements and near field ground motion data. In this study, we considered a northwest–southeast trending fault with a northeast dip retrieved from GPS coseismic data and aftershocks distribution. To analyze the detailed slip distribution in space and time, we used near field 3D Green’s functions provided by spectral-element method and a full time–space inversion technique. We find a complex rupture process with several slip patches distributed inside two main asperities. The slip map reveals a mean slip of 12.9 cm for a maximum slip of 27.3 cm leading to a Mw 6.47 for this event. The rupture initiates in the deepest portion of the fault at 20 km depth, and propagated upward up to 2 km depth to form the two asperities. The source time function of this event revealed two pulses corresponding to the two asperities, for a total duration time of about 16 s. Most aftershocks occurred near the upper boundary of the deepest asperity while no aftershocks are located close to the shallowest one. We infer that the locations of these slip patches are related to the surrounding fault systems that may have restricted the rupture propagation during the earthquake. 相似文献
Geothermal resources is one of the most practical and competitive new energy at present, and there is abundant geothermal resources in the new coastal region. The article get the three following conclusion through the geothermal geological condition by the drilling strata and the condition of the reducing test : stratigraphic division is done by the analysis of formation lithology and the drilling aging; the water yield is higher than 100 m3/h, the flow temperature is 67℃-71℃ ; the average geothermal gradient of the overlying strata is 3.08℃-3.33℃/100 m. 相似文献
The dynamics of a coupled concrete gravity dam-intake tower–reservoir water–foundation rock system is numerically studied considering two hollow slender towers submerged in reservoir of gravity dam. The system is investigated in the frequency-domain using frequency response functions of the dam and the towers, and in the time-domain using time-history seismic analysis under a real earthquake ground motion. The analyzes are separately conducted under horizontal and vertical ground motions. The coupled system is three-dimensionally modeled using finite elements by Eulerian–Lagrangian approach. It is shown that presence of the dam significantly influences the dynamic response of the towers under both horizontal and vertical excitations; however the dam is not affected by the towers. When the dam is present in the model, the water contained inside the towers has different effects if the foundation is rigid, but it alleviates the towers motion if the foundation is flexible. It is concluded that the effects of foundation interaction are of much importance in the response of tall slender towers when they are located near concrete gravity dams. 相似文献
Cyclic softening and strength loss of saturated clays during earthquakes is often an important consideration in engineering problems such as slope stability, dam/levee safety, and foundation bearing capacity. This study proposes a simplified procedure for evaluating cyclic softening (amount of strength loss) that may be expected in saturated clays during earthquakes and illustrates how to implement it in engineering analysis. The procedure has two main steps: (1) estimation of an equivalent cyclic shear strain amplitude and associated number of cycles induced in the soil mass by an earthquake; and (2) estimation of softening and strength loss in the soil mass. A key aspect of the proposed procedure is adoption of a strain-based approach to estimate cyclic softening as opposed to the widely used stress-based approach of liquefaction assessments. A threshold strain concept originating from the strain-based approach is first discussed and the development of a procedure is presented subsequently. The proposed procedure provides reasonable, first-order estimates of cyclic softening consistent with the other developed procedures. In addition, the capability of the procedure is demonstrated with two case histories identified as involving cyclic softening of clays. 相似文献