Study on one-dimensional consolidation of soil under cyclic loading and with varied compressibility

This paper presents a semi-analytical method to solve one dimensional consolidation problem by taking consideration of varied compressibility of soil under cyclic loading. In the method, soil stratum is divided equally into n layers while load and consolidation time are also divided into small parts and time intervals accordingly. The problem of one-dimensional consolidation of soil stratum under cyclic loading can then be dealt with at each time interval as one-dimensional linear consolidation of multi-layered soils under constant loading. The compression or rebounding of each soil layer can be judged by the effective stress of the layer. When the effective stress is larger than that in the last time interval, the soil layer is compressed, and when it is smaller, the soil layer rebounds. Thus, appropriate compressibility can be chosen and the consolidation of the layered system can be analyzed by the available analytical linear consolidation theory. Based on the semi-analytical method, a computer progra     

提高煤炭运输船舶周转效率的分析

从船舶装港等货时间、船舶加油、气象、船舶故障四个方面对影响船舶周转效率的因素加以分析,力求紧密联系实际,得出提高船舶周转效率的应对措施。     

钢筋混凝土T形柱最不利荷载角的研究

探讨钢筋混凝土T形柱最不利荷载角及其影响因素.利用编制的钢筋混凝土异形柱截面全过程数值分析程序,通过对多种工况下钢筋混凝土异形柱正截面承载力的计算分析,结果表明异形柱最不利荷载角的影响因素主要是轴压比;截面尺寸对最不利荷载角有些影响;而混凝土强度、纵筋配筋面积对最不利荷载角的影响很弱.研究结果为钢筋混凝土异形柱的设计和异形柱的可靠性分析提供参考依据.     

Shock and impact reduction in moderate and strenuous landing activities

Shock reduction has been well studied in moderate activities such as walking and running. However, there is a clear lack of research concerning shock wave transmission and reduction in more strenuous landing activities. In this study, we examined the impact of shock transmission and reduction in landing activities with varied mechanical demands. Ten active males were recruited for the study. They performed five successful step-off landing trials from each of five heights: 30, 45, 60, 75, and 90 cm. Right sagittal kinematics, ground reaction forces, and acceleration were recorded simultaneously. Impact frequencies were analysed using a discrete Fast Fourier Transform and power spectral density was computed. Increased range of motion for the ankle, knee, and hip joints was observed at higher landing heights. The peaks of the vertical ground reaction force, forehead and tibial accelerations, and eccentric muscle work by lower extremity joints were increased with increased landing heights. The peak head power spectral density was severely attenuated at higher frequencies but the peak tibia power spectral density did not demonstrate this trend. Shock reduction showed increased reduction at higher frequencies, but minimal changes across five landing heights. Unlike the responses observed for walking and running, the shock reduction did not show significant improvement with elevated mechanical demands.     

Vertical Ground Reaction Forces of Children during One- and Two-Leg Rope Jumping

Abstract

Sport offers opportunities for children to identify and resolve moral issues. Moral issues in sport have primarily been studied from the researcher's perspective, with the child's perspective relatively ignored. Thus, the purpose of this study was to explore the nature and content of the issues children experienced in sport. Interview participants consisted of 7 boys and 8 girls ranging in age from 10 to 12 years (M = 11.6 years, SD = 1.7) who had competitive youth sport experience. An inductive content analysis revealed that children identified issues surrounding three overall dimensions concerning fairness of adult's actions, negative game behaviors, and negative team behaviors. Specific examples of issues included unfair actions by coaches, disrespecting opponents, and selfish behavior in practice. The self-identified issues both confirmed and expanded upon the content found in hypothetical moral dilemmas in sport.     

微型桩水平承载特性的现场试验与数值模拟分析

水平承载微型桩在工程现场的静载试验,对比了不同桩长、不同抗弯刚度微型桩的水平承载特性,在实验研究基础上,对桩径、桩身模量等主要因素对微型桩水平承载特性影响进行的数值分析,得出结论:通过合理选择微型桩桩长、桩径以及桩身插设钢管等,可以提高水平承载微型桩的承载能力。     

基于模拟与整数规划方法的多码头集装箱港口装卸设备投资优化模型及其在上海港的应用

将模拟与整数规划相结合,提出一种适用于具有多码头的集装箱港口装卸设备的动态投资优化方法,得到港口装卸设备分码头、分年度的投资计划．模型从整体最优的观点出发,以港口内各集装箱码头的总成本最小为目标,对各码头进行统筹安排;此外,模型反映了码头效率和设备配比的动态性,因此更接近港口实际．     

黏性泥石流拦沙坝受力及稳定性分析

拦沙坝是泥石流防治中最常见和最有效的工程措施,稳定性计算是拦沙坝工程设计中的重要部分。在拦沙坝荷载组合与稳定性分析的基础上,推导空库工况和半库工况黏性泥石流过流时坝体稳定性系数的表达式,对比分析不同条件下坝体稳定性的变化规律。研究认为,在一定条件下,空库工况并不总是较危险工况,而半库工况在运行过程中表现出更不利的发展趋势;相同条件下半库工况时坝体稳定性系数随着库内淤积物厚度的增大而减小,即拦截相同来流时库内淤积越满坝体越偏于危险;研究还发现,迎水面坡比对拦沙坝稳定性的影响随着不断来流而逐渐减小,因此,建议在实际工程中可将迎水面设计为下部缓上部相对陡的折线型,以减少拦沙坝建设成本,提高工程价值。     

女子有氧健美操生理负荷的机能评定及意义

在阅读和研究国内外大量健美操相关文献资料和对参加有氧健美操锻炼的女性进行生理生化指标测试的基础上,对受试者的身体形态、机能、心肺功能、血液指标进行全面分析,从而建立科学的生理负荷评价依据。     

关于排球项目长竞赛期周末赛制的研究

通过对国内外球类项目周末赛制与集中赛制的比较研究，结合在北京体育大学进行的排球专项班周末赛制联赛的实验结果分析，认为：我国球类项目中长准备期集中赛制必将为长竞赛期周末赛制所代替；周末赛制能使练与赛、竞技运动与大众文化有机结合起来，在北京体育大学的试行取得了成功并可推广到高校体系及整个排球界。长竞赛期要求的竞技状态“平台现象”和周末赛制中周内负荷强度安排还有待进一步研究。