骊山滑坡Ⅱ区变形稳定性分析

骊山滑坡位于西安市临潼区骊山北坡,按稳定程度将其分为六个区.I区位于华清池正上方、三元洞上下,经详勘查明是潜在的黄土及浅层基岩沿破碎基岩中缓倾角断层滑坡,已于1997年至2002年进行了工程治理,目前该区基本稳定.II区为晚照亭下方的隆起部分,以破碎基岩错落为主,上覆第四纪崩坡积物,多年来一直在发生变形.本文结合II区地质地貌及地层岩性,对多年的监测资料进行综合分析,得出该区目前的稳定性评价,为进一步做好防灾减灾工作提供依据.     

高压静电水处理技术的研究现状及其展望

高压静电场水处理技术是近几十年发展起来的、当今水处理领域中的一门高新技术。在此介绍了国内外高压静电场水处理机理和应用研究现状,并对今后高压静电场水处理技术研究提出几点展望。随着对高压静电场水处理机理研究的不断加强和完善。以及对高压静电水处理技术与其它水处理技术的联合水处理工艺研究的突破。高压静电场水处理技术有望成为一种极具应用前景的高效水处理技术。     

搅拌条件对两种染料混凝气浮去除效果的影响研究

实验以七水硫酸镁及硫酸铝钾为混凝剂,十二烷基硫酸钠为浮选剂,研究了搅拌条件对酸性大红3R、还原深蓝BO混凝气浮去除效果的影响。结果表明,当搅拌转速为100r／min、搅拌时间为10min时,混凝气浮对酸性大红3R的去除效果较好,吸光度去除率为67．33％,色度去除率为69．23％;当搅拌转速为50r／min、搅拌时间为10min时,混凝气浮对还原深蓝BO的去除效果较好,吸光度去除率为84．33％,色度去除率为99．70％。     

关于伴生放射性污染源问题的讨论

本文根据国家规定公众照射年有效剂量和假设条件,建立了确定伴生放射性污染源的模型,将重庆市伴生放射性水平实地测量数据带入该模型计算,结果表明,共有8家企业确定为伴生放射性污染源,纳入伴生放射性污染源普查范围,符合重庆市实际情况。     

近地表土壤水分条件对坡面农业非点源污染物运移的影响

采用人工模拟降雨实验,研究了近地表土壤水分条件,尤其是土壤水分饱和条件对土壤侵蚀过程中农业非点源污染物运移的影响.结果表明,前期近地表土壤水分条件对土壤侵蚀过程中农业非点源污染物的迁移有着很大影响.饱和含水量时径流及泥沙中非点源污染物的流失浓度和流失量大于非饱和含水量,且前期近地表土壤含水量越大,径流及泥沙中农业非点源污染物的流失浓度和流失量越大.土壤氮素的主要流失途径是降雨所产生的径流,约占总流失量的90.4%～99.8%;土壤磷素的流失途径是降雨径流和侵蚀产沙,分别占总流失量的2.67%～23.5%和76.5%～97.3%.同时,土壤质地对磷素养分的流失有很大影响,杨凌土随泥沙流失的DP浓度和流失量均大于安塞黄绵土.最后,提出了采取最佳管理措施等控制农业非点源污染的针对性建议.     

厦门市酸雨分布特征与气象条件的关系分析

厦门市是我国酸雨控制区之一。文章利用1992～2005年厦门市的探空、降水量和酸雨资料来分析厦门市不同气象条件对降水酸度、酸雨出现率的影响,分析结果表明:(1)不同等级的降水对降水酸度和酸雨出现率有明显影响,相对于夏、秋二季,冬、春二季的降水酸度更酸,酸雨出现率更高。(2)K指数、850～700hPa层的冷暖平流对酸雨污染没有明显影响。(3)酸雨出现率随着1500m高空风速的增大而增多,风向变化对降水酸度和酸雨出现机率的影响不大。(4)逆温对酸雨污染的有一定的影响。     

Assessment of temporal stability in risk factors of crashes at horizontal curves on rural two-lane undivided highways

Introduction: Safety of horizontal curves on rural two-lane, two-way undivided roadways is not fully explored. This study investigates factors that impact injury severity of such crashes. Method: To achieve the aim of this paper, issues associated with police-reported crash data such as unobserved heterogeneity and temporal stability need to be accounted for. Hence, a mixed logit model was estimated, while heterogeneity in means and variances is investigated by considering four injury severity outcomes for drivers: severe injury, moderate injury, possible injury, and no injury. Crash data for the period between 2011 and 2016 for crashes that occurred in the state of Oregon was analyzed. Temporal stability in factors determining the injury severity was investigated by identifying three time periods through splitting crash data into 2011–2012, 2013–2014, and 2015–2016. Results: Despite some factors affecting injuries in all specified time periods, the values of the marginal effects showed relative differences. The estimation results revealed that some factors increased the risk of being involved in severe injury crashes, including head-on collisions, drunk drivers, failure to negotiate curves, older drivers, and exceeding the speed limits. Conclusions: The hypothesis that attributes of injury severity are temporally stable is rejected. For example, young drivers (30 years old and younger) and middle-aged drivers were found to be temporally instable over time. Practical applications: The findings could help transportation authorities and safety professionals to enhance the safety of horizontal curves through appropriate and effective countermeasures.     

Impact of safety attitude,safety knowledge and safety leadership on chemical industry workers’ risk perception based on Structural Equation Modelling and System Dynamics

In chemical industry, major accidents occur occasionally. Past research has demonstrated that risk perception was relevant to safety as it might affect the behavior, which could exert influence on the probability of accidents. It is important to adjust workers' risk perception to reduce accidents in chemical industry. To achieve this goal, some key influencing factors of workers’ risk perception of were identified from 3 aspects including safety attitude, safety knowledge and safety leadership. This was accomplished by gathering empirical data from 287 workers employed in 6 Chemical plants in Jiangsu, China. The model of influencing factors of risk perception for workers was established based on Structural Equation Modelling (SEM), and the path coefficients and weights were analyzed by the SEM. On that basis, the System Dynamics (SD) model of risk perception for workers was established. The study findings revealed safety attitude and safety leadership have a direct positive impact on perception of risk probability and perception of risk severity, safety knowledge has a direct positive impact on perception of risk severity, while safety knowledge has no direct positive impact on perception of risk probability. The findings of the study can provide theoretical supports and method guidance for adjusting the risk perception of workers in chemical industry.     

含孤石土质边坡稳定性及破坏特征的数值分析*

为探究花岗岩风化形成的风化球孤石对边坡稳定性及破坏特征的影响,利用摄影测量和数字图像处理技术,对大量的孤石进行拍照及处理,建立大量具有各种形状的孤石模型,从所建立的孤石模型中选取具有不同形状参数的孤石,将其导入ABAQUS软件,建立含有孤石的边坡模型,进行有限元强度折减分析。结果表明:孤石的位置和大小会对边坡的安全系数产生规律性影响,而孤石的形状对边坡安全系数的影响表现出不确定性;孤石对边坡破坏特征产生影响,塑性应变区发展过程及位移场分布在孤石处与均质边坡相比均有较大变化。     

分区协同开采下矿柱力学响应与稳定性分析*

为解决某钒铁矿经多年开采后,由于钒铁矿矿区赋存条件变化导致开采相互制约、资源利用率低、矿柱积压矿量大以及井下采空区隐患大等问题,制定“保钒采铁、分区协同”的开采方案。通过矿柱强度理论对矿柱的强度和承受载荷进行计算,进而通过矿柱安全系数来判断矿柱的稳定性。通过FLAC3D软件对东、西区铁矿体进行数值模拟研究,通过对开挖后的位移云图、应力云图以及塑性区分布图来分析矿柱的稳定性。研究结果表明:针对某钒铁矿东、西区提出的嗣后膏体微胶结充填法及中区提出的分段空场法转分段崩落采矿法可提高矿柱的稳定性。