三峡工程茅坪溪防护坝沥青混凝土心墙工作性态研究

本文对沥青混凝土心墙的温度、应力、应变、位错变形进行分析,通过分析心墙底座压应力为1．37-1．55MPa;心墙上下游面均为压应变,上下游面平均压应变分别为-21．53kμε和-19．30kμε;心墙与基座位错变形多在-1．93mm以下,心墙与过渡料之间的垂直位错变形在-3．85～_48．59mm之间,心墙上下游水位差37．89m,以上说明心墙防渗效果好,应力应变工作性态正常。     

Role Stressors and Retail Performance: The Role of Perceived Competitive Climate

Cognitive appraisal theory is used to investigate the influence of perceived competitive climate in the retail store upon the relationship between three role stressors (i.e., role ambiguity, role conflict, and family-work conflict) and job efficacy, job satisfaction, and the self- and supervisor-rated performance of retail professionals. Results indicate that the effect of role ambiguity on job efficacy is moderated by perceived competitive climate, such that the harmful effect of role ambiguity is lessened when competitive climate is high, thus highlighting a potential benefit of stress reduction through an increase in perceptions of competitive climate. In addition, the influence of job satisfaction on supervisor ratings of performance is moderated by perceived competitive climate, such that higher levels of job satisfaction result in improved supervisor ratings when the competitive climate is perceived to be high.     

基于应力波法的锚杆(索)锚固质量动力检测数值模拟研究

锚杆(索)大量应用于边坡工程加固,为保证锚杆(索)发挥作用,一般采用应力波法对其锚固质量进行检测,检测的2个主要指标是:锚杆(索)长度和缺陷段的位置。为此,在ANSYS/LS-DYNA中建立锚固体应力波动力分析模型,将小锤对锚杆(索)的敲击作用等效为小锤按一定激发速度v₀与锚杆(索)的碰撞,并在锚杆(索)端头断面中点采集应力波信号。经算例与理论研究成果对比,验证了数值模型的可行性,同时,分析了小锤弹性模量和激发速度v₀的取值对应力波信号的影响,研究了应力波法判别缺陷段位置的准确性,及对比了端头激发与端头和底端同时激发这2种方式在锚杆(索)质量检测中的适用性。研究结果表明:①小锤弹性模量的增大仅对初始应力波信号有增强作用,对经锚固体底端一次反射回的应力波信号影响不大,而小锤激发速度v₀的增大对初始和经锚固体底端一次反射回的应力波信号均有利,且与后者成线性比例关系;②应力波法对锚固体缺陷段位置的判别较为可靠,且缺陷段越饱满判别准确性越高; ③端头和底端同时激发方式缩短了反应锚固体断面变化处和底端位置的应力波信号时间,因而有利于工程应用。     

部分翼缘加强型钢板混凝土连梁的有限元分析

通过Abaqus建立钢板混凝土连梁模型对原始实验[1]进行模拟分析,分析结果与原始实验吻合良好,有限元分析表明:钢板混凝土连梁的墙梁连接处钢板的边缘在剪拉应力的作用下率先进入屈服,而配有工字型截面的型钢混凝土连梁其翼缘并不能沿跨度全部发挥作用,因此提出了在钢板混凝土连梁的钢板端部增加翼缘板形成部分翼缘加强型钢板混凝土连梁的思想,为了探究这种新型组合连梁的加强翼缘的几何尺寸对模型的力学性能的影响,以翼缘板的长、宽、高建立三组有限元模型并进行分析,并通过有限元程序对其进行初步设计与分析。结果显示这种组合连梁在提高连梁承载力与改善钢板应力分布方面具有良好的效果,分析结果表明:增加翼缘长度、宽度与厚度对均能改善钢板应力分布,但增加翼缘厚度对改善应力分布效果不明显。随翼缘板的长度、宽度、厚度的增加,模型承载力以及梁端转角逐渐增大;但是随着翼缘厚度增加,模型承载力提高以及梁端转角增加效果不显著。更多还原     

地铁明挖隧道与上方高层建筑共建方案研究

基于某地铁隧道与上方高层建筑共建方案,借助于ＭｉｄａｓＧＴＳ大型岩土仿真软件,针对地铁隧 道与高层建筑地下室结构合建、分离两个方案进行研究,对比分析了地铁明挖隧道的内力与位移情况。 研究表明:高层建筑施工会导致基坑底部以下地层产生明显的沉降变形;结构合建方案会导致下方明挖 隧道产生显著的附加应力与变形,对结构承载力与稳定性产生较大影响;而结构分离方案则能利用地下 室底板下设置的转换体系将高层建筑附加荷载有效地传递到地层深处,进而有效地减小下方明挖隧道 的附加应力与变形。研究结论可为类似工程提供借鉴与参考。     

不同施工方法下锦屏大理岩隧洞松弛范围及微观破裂方式

TBM(Tunnel Boring Machine全断面隧道掘进机)法和钻爆法是地下工程开挖的2种主要方法,不同施工方法导致围岩的扰动程度、变形破坏、自稳性、加固措施均不相同,要准确把握这些宏观特征,必须从微观上分析岩石的力学特征。以最大埋深2 525 m的锦屏二级水电站引水隧洞为研究对象,对不同开挖条件下的大理岩进行了电镜扫描测试、松弛深度检测,分析不同开挖条件下岩石的破坏方式和松弛范围。试验结果表明:在岩石破坏断面形貌上,TBM开挖条件下的岩石断口多为沿晶面擦花和切晶擦花,破坏机理以剪切为主,而钻爆法以拉断破坏为主;在松弛深度方面,钻爆法开挖下的围岩松弛深度大于TBM开挖下的围岩松弛深度40～100 cm。以上试验成果为相似地质条件下的岩石破坏机理和加固措施提供借鉴。     

二滩拱坝无应力计异常测值的修正方法研究

2009年,在小湾拱坝的安全监测中首次发现,部分无应力计的工作性态出现异常, 其测值反映的不全是坝体的自由变形,从而严重影响了应变观测成果的可靠性。针对无应力计的异常测值,从研究自生体积变形变化规律着手,结合统计分析方法,提出了判别异常数据的依据、标准和方法,建立了无应力计异常测值的修正方法,并对二滩拱坝部分无应力计观测成果进行了鉴别和修正处理。研究表明,提出的修正方法是有效的,修正后的成果反映了二滩坝体的实际应变。     

Reluctant employees and felt stress: The moderating impact of manager decisiveness

Job stress is an integral part of the organizational landscape and particularly severe in the sales profession. A host of studies have looked at felt stress, its antecedents, and consequences. This research examines how employee resistance to change and a manager's decisiveness affect the salesperson's felt stress and turnover intentions. This study shows that the salesperson's resistance to change is positively associated with felt stress. Study results also show that the impact of an employee's resistance to change on felt stress is moderated by a manager's decisiveness. Model hypotheses are tested with responses from 255 bank salespeople in India.     

The influence of ethical climate on marketing employees' job attitudes and behaviors

In this study, two data sets were used to test the validity of the Babin, Boles, and Robin (Babin BJ, Boles JS, Robin DP. Representing the perceived ethical work climate among marketing employees. J Acad Mark Sci 2000;28(3):345-358.) measure of ethical work climate and its relationship with role stress, pay satisfaction, supervisor satisfaction, organizational commitment, performance, and turnover. The results indicated that ethical work climate is a multidimensional construct and that its dimensions influence marketing employees' job attitudes and job behaviors. Facets of job satisfaction and organizational commitment mediated the relationship between ethical work climate and turnover intentions and turnover.     

Role stress,burnout and their effects on frontline hotel employees' job performance: evidence from Northern Cyprus

Based on data obtained from frontline hotel employees in Northern Cyprus, this study investigated the effects of role stress and burnout on job performance. It was found that role ambiguity decreased job performance while role conflict enhanced job performance. The results indicated that diminished personal accomplishment exerted a significant negative influence on job performance whereas the rest of the burnout dimensions did not. The results further showed that both role conflict and ambiguity exacerbated emotional exhaustion and depersonalisation. Role ambiguity was found to have a significant positive relationship with diminished personal accomplishment whereas role conflict was not. Copyright © 2007 John Wiley & Sons, Ltd.