地震断裂带高铁大跨拱桥深基坑钢板桩围堰支护试验与监测

针对大跨度高速铁路拱桥建设对深基坑开挖施工的安全性要求,为了研究钢板桩围堰支护在大跨度高速铁路拱桥深基坑施工中的可行性,以新建徐盐高铁徐洪河特大桥工程项目为依托,通过数值模拟及现场试验监测,对深基坑钢板桩围堰支护在施工过程中的形变及受力情况进行分析。结果表明:通过有限元模拟分析,钢板桩围堰最危险受力点处于钢板桩中部、中上部及四角连接处,围堰第4道内支撑内力较其他3道内支撑大。整个施工过程中工况5为施工最不利工况。由监测结果可知,在施工过程中钢板桩单日最大位移值为2.8mm,最大累计位移值为24.0mm,均未达到预警值,施工过程中钢板桩形变稳定。钢支撑轴力受基坑周边荷载的影响明显,围堰钢支撑最大压力值为147.31kN,最大拉力值为24.95kN,未达到预警值,结构安全。研究结果可供同类型工程施工参考。     

堆积体内部裂隙对降雨入渗的影响

降雨条件下滑坡体稳定性与裂隙诱发入渗密切相关。为了探究裂隙发育对堆积体降雨入渗的影响,以澜沧江某巨型堆积体坡表发育的裂隙现象为出发点,设计了均质堆积体和主-次裂隙堆积体2种模型。通过室内物理模拟试验及数值分析,并结合土体中的含水率、基质吸力、湿润锋迁移速度及深度的变化趋势可得出以下结论:裂隙型堆积体在降雨1 h和观测23 h的整个时间段内,其湿润锋迁移变化趋势可归纳为入渗加速→峰值→入渗减速→趋向于0;裂隙的存在为雨水入渗提供了有利的通道,雨水可到达土体深部,形成暂态饱和区,随降雨结束又逐渐消散;降雨在裂隙型发育的堆积体中的入渗过程可分为4个阶段,即前期完全入渗、裂隙下方强烈入渗、补偿加速入渗及水平侧渗。研究结果可为后续滑坡复活机理和稳定性评价提供参考。     

大坝安全监测智能感知与智慧管理技术研究及应用

水库大坝安全监测是工程安全的重要保障措施,亟需结合新一代信息技术,提升大坝安全监测能力。系统总结了长江科学院近年来在大坝安全监测智能感知与智慧管理技术方面的研究及应用工作,通过研发系列化智能传感器、智能采集单元和物联网感知平台,建设统一的大坝安全监测数据资源池,开发通用化安全监测云服务系统,搭建专业数据挖掘平台和综合可视化应用,实现了大坝安全监测数据感知、传输、管理、分析及展示全链路应用,形成了大坝安全监测全生命周期智慧解决方案。研究成果已在乌东德、溪洛渡、向家坝、大藤峡等100余项水利水电工程中成功应用,为保障工程建设及运行安全发挥了重要的支撑作用,具有很好的推广应用前景。     

基于水表误差曲线重建的供水系统表观漏损量估算方法及应用

在分类用户用水模式分析的基础上,考虑选取5个特征流量进行水表误差曲线重建,对水表误差值进行修正,建立了基于水表误差曲线重建的表观漏损量估算方法.利用该方法对苏州市研究区域内新建小区、老旧小区、工业、商业、学校和医院等6类用户的水表误差进行修正,各水表的误差修正值分别为-0.25％、-4.1％、-4.59％、-2.03％、-5.74％、-0.34％,据此计算得到各类用户的表观漏损水量分别为7.41万m3、103.42万m3、292.50万m3、28.29万m3、167.83万m3、2.82万m3.与传统方法相比,建立的方法考虑到用户用水模式对水表误差曲线的影响,对表观漏损水量估算更为准确,能为用水行为类似的苏南地区的表观漏损水量估算提供参考.     

襄阳市"市域乡镇打捆模式"污水治理案例分析及总结

襄阳市在乡镇污水治理方面加大投入,创新实施"市域乡镇打捆模式",实行"四个统一",在厂网一体化建设、厂网智慧化运维等方面摸索出了优势经验.对襄阳"市域乡镇打捆模式"污水治理案例进行分析,总结出一条乡镇污水治理的"襄阳路径".     

丙乳砂浆防碳化修复技术在坝体廊道除险加固中的应用

大塅水库作为铜鼓县唯一一座大型水库,水库安全运行是铜鼓县社会经济发展的重要保障.大塅水库除险加固工程中使用丙乳砂浆对坝体廊道进行防碳化修复处理,文章介绍了丙乳砂浆防碳化修复施工工艺及相关技术参数与施工方法质量控制措施,处理后效果良好.     

养老基金筹集模式的实证分析

当前的养老制度改革是关注的焦点。本文首先将从介绍现存的筹集模式入手,试图换个角度来思考在人口老龄化背景下的我国养老金基金制度,实证分析模式选择对于缴费率等的影响,并基于此,讨论未来改革的方向。     

Do homeowners achieve more household wealth in the long run?

Despite the public’s faith in homeownership as a vehicle for wealth creation, there are surprisingly few empirical studies of the independent impact of homeownership and its duration on household wealth accumulation. This paper provides the first empirical evidence that homeownership, after controlling for other drivers of wealth accumulation, is positively and significantly associated with wealth accumulation over time. Using the Panel Survey of Income Dynamics, it examines the influence of housing tenure choices between 1989 and 2001 on household net wealth levels in 2001 after controlling for initial wealth in 1989, location, income, education, and other family and personal characteristics that might influence the rate of wealth accumulation. Importantly, the models used also control for the tendency of households to accumulate wealth between 1984 and 1989 (five years prior to the studied period). This approach is used to address the possibility that an unobserved variable—the propensity to save or accumulate wealth—may be associated with both the probability and duration of homeownership and the rate of wealth accumulation. All else equal, those who owned homes and owned for longer periods of time had significantly higher household net wealth by 2001. These results are compelling because house price appreciation over the period was near its long-run average while stock gains were above and real rent increases below their long-run averages. Hence, the findings are suggestive of a positive influence of ownership over long periods on net wealth, even during a period when alternative investments produced higher than normal returns and rents grew slowly. This is especially important because the overwhelmingly majority of households do not sell their homes shortly after buying them. In our sample, those who became owners typically owned for 7 years. Furthermore, most households that bought during a period of declining real home values in the early 1990s continued to own their homes for at least eight years and came out well ahead of those who did not own.     

对供应链中"牛鞭效应"综合治理策略的探讨

通过文献综述,讨论了供应链中牛鞭效应的现象和成因，提出了减轻和消除该效应的对策以及进一步研究方向。     

拓宽扶贫思路,构建和谐社会

改革开放以来,我国扶贫工作成绩显著.全国贫困人口已从30%降至4%,但目前无论相对贫困还是绝对贫困,情况仍然十分严重.绝对贫困方面,全国农村低于国家规定的贫困线(人均年收入667元人民币)的人口有2 600多万,其温饱问题还未完全解决;全国城镇低于低保线(人均月收入159元人民币)的人口有2 200多万,生活状况仍十分艰难.