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991.
近年来关于桩基水平内力的研究已取得一系列新的成果,虽然采用多种方法计算的基桩水平内力与实测值比较接近,但其计算过程比较复杂,采用的计算参数多由土工试验得出,受人为因素影响较大。为进一步简化桩基水平内力计算并提高计算精度,根据修正的双参数法和有限差分原理推导桩基水平内力的计算公式,可求得桩身各节点的水平内力。 相似文献
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In this study, we develop a multilane first-order traffic flow model for freeway networks. In the model, lane changing is considered as a stochastic behavior that can decrease an individual driver’s disutility or cost, and is represented as dynamics toward the equilibrium of lane-flow distribution along with longitudinal traffic dynamics. The proposed method can be differentiated from those in previous studies because in this study, the motivation of lane changing is explicitly considered and it is treated as a utility defined by the current macroscopic traffic state. In addition, the entire process of lane changing is computed macroscopically by an extension of the kinematic wave theory employing IT principle; moreover, in the model framework, the lane-flow equilibrium curve is endogenously generated because of self-motivated lane changes. Furthermore, the parsimonious representation enables parameter calibration using the data collected from conventional loop detectors. The calibration of the data collected at four different sites, including a sag bottleneck, on the Chugoku expressway in Japan reveals that the proposed method can represent the lane-flow distribution of any observation site with high accuracy, and that the estimated parameters can reasonably explain the multilane traffic dynamics and the bottleneck phenomena uphill of sag sections. 相似文献
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Data from several freeway merges reveal that, contrary to some previous findings, merge ratio can vary within a site with respect to the merge outflow and that the existing merge ratio estimates based on lane counts are not able to predict this within-site variation. Furthermore, the merge ratios estimated based on two well-known merging principles, “fair-share” and “zipper,” are found to be inaccurate for merges where merging streams compete directly due to a lane drop. In light of these findings, we estimate merge ratios using lane flow distribution (LFD) to better predict between and within site variations of merge ratio. In addition, we propose a merging principle specific for merges with a single lane-drop. The model was developed to better represent observed non-uniform redistribution of merging flow not captured by the current merge ratio estimation methods and merging principles. Empirical observations show that the proposed methods are able to improve merge ratio estimates, reproduce within-site variations of merge ratio, and represent more accurately non-uniform redistribution of merging flow dependent on the merge geometry. 相似文献
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黄军生 《武汉船舶职业技术学院学报》2007,6(4):76-79
随着企业人才竞争的加剧,越来越多的企业开始采用宽带薪酬模式来吸引人才,留住人才。宽带薪酬固然拥有很多优点,但是很多企业在实施过程中走入了误区。本文从员工高层次需要满足、薪酬的外部竞争性、绩效管理等几个方面分析了宽带薪酬存在的缺陷,并提出了制定宽带薪酬的有效流程,为企业在引入宽带薪酬之前提供了有益的思考。 相似文献
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简要介绍了冲击式压路机的工作原理和在路基施工中对提高压实度,减少沉降量的作用机理及其应用效果。 相似文献
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