Water conservation areas (WCAs), as an essential part of the ecosystem, are closely related to the sustainable development of socioeconomic system. To disclose the ecological and economical effects of the WCA, this paper clarifies the structure of the water resource-ecology-economy (ECC) system of the WCA, and sets up system dynamic models (SDMs) of the three subsystems under the ECC system. The dynamic evolution of the subsystems and the ECC system was simulated. Based on the feedbacks of the variables and objectives, the authors analyzed the internal correlations between water resource management, eco-environment, and economic development in the SDM, and predicted the trends of the three sub-systems. The proposed SDMs were proved valid through the analysis of a typical case. The analysis results show that the SDM should, relying on natural resources, reasonably grasp the functions of ecological regulation and market regulation, and correctly handle the relationship between ecological benefit and economic benefit.
Through summing up, statistical parameters of steel material property based on new standards and statistical parameters of geometry property of steel-concrete composite beams are obtained. Testing datum of steel-concrete composite beam in bending state and its connecting piece in shearing state is roundly collected. Then indeterminateness statistical parameters of computation modes and resistance statistical parameters of steel-concrete composite beams are obtained.
Fiber-reinforced polymer (FRP) materials are suitable as reinforcement owing to their excellent properties. To reveal the reinforcement mechanisms and effectiveness of FRP materials, a model was proposed for testing the mechanical properties of FRP-reinforced subgrade supporting individual footing. A non-reinforced case and eight reinforced cases were designed with variables such as the arrangement style and number of reinforcements. The soil failure patterns in the nine test cases were observed, settling of ground and reinforcement strains were tested, and the variations of ground settlement and reinforcement strain with footing pressure were obtained. The reinforcement mechanisms and effectiveness were determined by comparative analysis. Results show that the ultimate bearing capacity of subgrade increases by 450% and the ultimate settling of ground decreases by 41% for the case ch (subgrade horizontally reinforced with double plates) compared with the case an (subgrade without reinforcement). As for the case jv (vertically reinforced subgrade) with longer and higher vertical reinforcements, the ultimate bearing capacity of subgrade increases by 261%, whereas the ultimate ground settlement decreases only by 4%. This study can provide a reasonal arranging for the layout and number of reinforcements to attain a favorable reinforcing effect.
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