Applied Mechanics and Materials Vols. 580-583

Abstract: For studying the impacts of the tributaries confluence on the hydrological processes in the downstream reaches of the four cascaded reservoirs in the downstream of Jinshajiang River, this paper simulated the daily discharge at the outlet of the cascaded reservoirs and along the reserve mainstream in typical years with the operation programming of the reserve and MIKE11 hydrodynamic model, and eco-hydrology indicators were selected and calculated by IHA to quantify the hydrology process. The result showed that at Xiangjiaba Gauge Station discharge on April and May increased by about 100%, the discharge in low flow year decreased by 50% and the timing of annual 1-day minimum discharge has significantly alteration. The confluence of Minjiang River could effectively mitigate the impacts of the cascaded reservoirs on eco-hydrology of the downstream of the confluence, but the mitigation of others three tributaries were not significant. Moreover the pre-flood high flow in the downstream of the Minjiang River confluence increased by 50%, and other indicators alteration were not significant.

Abstract: The sequential quadratic programming method is introduced in arch dam shape optimization design. In the optimization computation, the arch dam volume is taken as objective function, and the calculation is realized by automatically considering loading process, equivalent stress computation and simulation of shape optimization for arch dam based on FEM. A parabola arch dam is used as a numerical example. The result shows that the optimized figure is much safer and more practical, which indicates that the SQP method is an effective way for optimization design of arch dam shape.

Abstract: After the completion of the hub on river, its scheduling unsteady flow generated an adverse impact on the downstream navigation. In this paper, according to the unsteady flow data of PingBan hub in Nanpanjiangjiang River in Guizhou province, researched unsteady flow spread characteristics and rule in hub downstream channel. Studies have shown that: unlike general water level changes in hub downstream, the waterlevel amplitude attenuation along is not obvious in researched reach; Clear the concept of unsteady flow additional velocity、additional slope,through this theory reveals the ship ascending rapids mechanism difficultly under unsteady flow condition. On this basis, proposed channel regulation methods and measures in hub downstream, which provided support for the hub downstream channel regulation.

Abstract: 3D numerical simulation is carried out for the water flow in stilling basin with X shaped flaring gate pier when the radial gate uses four different opening velocities. The space-time change law of hydraulic characteristics is obtained. The water level in the stilling basin is relatively higher while using lower opening velocities during the processes. The negative pressure exists on weir surface while the relative opening degree is less than 0.55; the maximal pressure on the slab of ogee section and stilling basin increases and moves to downstream with the gate opening. The results can provide important basis for shape optimization of practical engineering.

Abstract: Using finite element method, the seismic responses of an exposed steel penstock in a hydropower station were analyzed. The results show that the penstock is constrained weakly due to the expansion joint and sliding supports, so the penstock can adapt to the deformation during the earthquake well, and the stress caused by the earthquake is small which will be benefit for the strength and safety of the penstock. However large acceleration and displacement in transverse direction may be induced under strong earthquake, in addition, the penstock will be likely to jump apart from supports in vertical direction. So it is better to equip caging device to limit transverse sliding and vertical jumping in an appropriate range in order to ensure the safety and stability of the whole structure.

Abstract: Based on the regulating principles, the modes of joint regulation and storage of surface water and groundwater in Rushan River Basin are simulated using multi-objective programming method. The study suggests two modes as “two dry years and one normal year” and “four dry years and one wet year”. The results indicate the guarantee rates of water supply are improved, with increasing the exploitation quantity in dry years and the recharge in wet years. The study provides a strong guarantee for water resources regulation and promotes the sustainable development of regional water resources.

Abstract: Using fuzzy mater-element method, the comprehensive utilization efficiency of rain-flood resources in Rushan River is assessed. The uncertainty of the comprehensive utilization efficiency is processed by the fuzzy principle. Then the representative indexes are selected, and the standard values of indexes are indicated. After normalization, the close degree and weight coefficient are calculated. On basis of that, the rating membership of the comprehensive utilization efficiency is for grade II, equal “good”. So the paper concludes that the utilization of rain-flood resources in Rushan River Basin is feasible and effective. It provides follow-up support for the research of the utilization of rain-flood resources.

Abstract: Yamen channel is the important sea-route from Yinzhou Lake to Gaolan harbor in Zhuhai city through Huangmaohai Sea. Based on the recent hydrologic data and the seabed change, the numerical model is validated, and some advanced dredging plan for Yamen channel is simulated in the movement of tidal current and sediment, and the number of the sediment silting in channel is calculated. The result shows that there are some preponderance for the east channel in the tidal current and sediment, and the sediment is filling up in the mouth bars mostly. Moreover, the east channel has the potential to improve the channel standard, which can be developed firstly in the common condition.

Abstract: The foundation of Wenzhou shoal project is soft and deep. The stability control issue of building seawalls on the deep soft foundation was solved by using a composite foundation treatment of plastic drainage plates and geotextile, combining with the in-situ monitoring. The in-situ monitoring data of Wenzhou shoal project was analyzed and the settlement prediction analysis was conducted. Basing on the conventional exponential curve fitting method, the settlement prediction model is presented for the classified construction on soft foundation. Considering the non-linear of deformation and soil consolidation with load changes, the model used the settlement deformation characteristics under the last load to predict the settlement development under the next load.

Abstract: In this paper, differences by using selected three typical specifications—DL/T 5141-2001 (Chinese), ASCE No.79 in the version of 1993(American) and ASCE No.79 in the version of 2012 (American)—in structural design of exposed steel penstock were explored. A practical example about exposed penstock laid on ground applied in hydropower station was also used to analyze specifications clearly. The result shows that the main differences between Chinese and American specifications are allowable stress and load combination. The former is direct factor of calculating exposed penstock shell thickness. Therefore, ASCE No.79 (2012) designs the minimum wall thickness, followed by DL/T 5141-2001 and the last is ASCE No.79 (1993), which is correspondingly contrary to sort by allowable stress. Basically, ASCE No.79 (2012) defines lower safety coefficient for exposed penstock, which is identical with authoritative rules of pressure vessels in the U.S.A and EU. The safety of DL/T 5141-2001 has been proved via rich engineering experience and this specification is recommended for Chinese projects. Besides, ASCE No.79 (2012) is recommended.