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Prediction of vertical PM2.5 concentrations alongside an elevated expressway by using the neural network hybrid model and generalized additive model

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Frontiers of Earth Science 2017年第2期11卷 347-360页

作者： Ya GAO Zhanyong WANG Qing-chang LU Chao liu Zhong-Ren PENG Yue YU Center for ITS and UAV Applications Research State Key Laboratory of Ocean Engineering School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 200240 China Department of Urban and Regional Planning University of Florida FL 32611-5706 USA Department of Electrical and Systems engineering University of Pennsylvania PA 19104-6314 USA

A study on vertical variation of PM2.5 concentrations was carried out in this paper. Field measurements were conducted at eight different floor heights outside a building alongside a typical elevated expressway in downtown Shanghai, China. Results show that PM2.5 concentration decreases significantly with the increase of height from the 3rd to 7th floor or the 8th to 15th floor, and increases suddenly from the 7th to 8th floor which is the same height as the elevated expressway. A non-parametric test indicates that the data of PM2.5 concentration is statistically different under the 7th floor and above the 8th floor at the 5% significance level. To investigate the relationships between PM2.5 concentration and influencing factors, the Pearson correlation analysis was performed and the results indicate that both traffic and meteorological factors have crucial impacts on the variation of PM2.5 concentration, but there is a rather large variation in correlation coefficients under the 7th floor and above the 8th floor. Furthermore, the back propagation neural network based on principal component analysis （PCA-BPNN）, as well as generalized additive model （GAM）, was applied to predict the vertical PM2.5 concentration and examined with the field measurement dataset. Experimental results indicated that both models can obtain accurate predictions, while PCA-BPNN model provides more reliable and accurate predictions as it can reduce the complexity and eliminate data co-linearity. These findings reveal the vertical distribution of PM2.5 concentration and the potential of the proposed model to be applicable to predict the vertical trends of air pollution in similar situations.

关键词： vertical variations principal component ana-lysis back propagation neural network generalized additivemodel urban elevated expressway

超高性能混凝土预制板-叠合剪力墙抗震性能研究

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地震工程与工程振动 2024年第3期44卷 96-107页

作者：常亚峰尹文哲侯亚鹏曹小杉师俊平梁兴文陕西省建筑科学研究院有限公司陕西西安710082 西安理工大学土木建筑工程学院陕西西安710048 西安建筑科技大学土木学院陕西西安710055

通过对1片现浇混凝土剪力墙和4片超高性能混凝土(ultra-high performance concrete, UHPC)预制板-叠合剪力墙抗震性能试验,研究了其滞回性能、抗弯承载力、延性、刚度和耗能能力等指标,分析了高宽比、聚乙烯泡沫(expanded polystyrene, ... 详细信息

通过对1片现浇混凝土剪力墙和4片超高性能混凝土(ultra-high performance concrete, UHPC)预制板-叠合剪力墙抗震性能试验,研究了其滞回性能、抗弯承载力、延性、刚度和耗能能力等指标,分析了高宽比、聚乙烯泡沫(expanded polystyrene, EPS)芯模置换和竖向钢筋连接方式对其抗震性能的影响。结果表明:与现浇混凝土剪力墙相比,UHPC预制板-叠合墙具有优异的抗震性能,最大受弯承载力增大;UHPC预制板和钢筋桁架可较好地与空腔内现浇混凝土协同工作;UHPC叠合墙的滞回曲线、骨架曲线和刚度退化曲线与现浇混凝土剪力墙趋势基本一致;在本试验剪力墙的高宽比范围内,高宽比越小,UHPC预制板-叠合墙的受弯承载力和刚度越大,耗能越差;EPS芯模置换可提高叠合剪力墙屈服后的耗能能力,降低了UHPC叠合墙的延性;仅采用暗柱竖向钢筋与底座进行连接,对UHPC叠合墙的受弯承载力和耗能影响较小,但却可以很大程度方便施工。

关键词： UHPC预制板叠合剪力墙抗震性能置换芯模连接钢筋

基于组合权重的文一路地下空间开发适宜性评价

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科学技术与工程 2024年第20期24卷 8804-8812页

作者：孙雅珍戚亚茹杨大勇胡智王金昌林坤沈阳建筑大学交通与测绘工程学院沈阳110168 浙江省交通运输科学研究院杭州310039 浙江大学建筑工程学院杭州310058 浙江大学平衡建筑研究中心杭州310058

对地下空间开发适宜性进行科学、合理的评价,是避免地下空间资源浪费,保证其健康可持续发展的前提。基于地形地貌、工程地质、水文地质、不良地质作用和建设现状构建地下空间开发适宜性评价指标体系,通过数值模拟确定盾构隧道施工的影... 详细信息

对地下空间开发适宜性进行科学、合理的评价,是避免地下空间资源浪费,保证其健康可持续发展的前提。基于地形地貌、工程地质、水文地质、不良地质作用和建设现状构建地下空间开发适宜性评价指标体系,通过数值模拟确定盾构隧道施工的影响范围,完成建设现状评价指标分级量化;分别采用层次分析法和熵权法计算评价指标主观和客观权重,通过博弈论确定组合权重。在此基础上,利用综合指数法对杭州市文一路地下空间开发适宜性进行评价。通过评价结果对比分析和学院路地下工程实例,验证了评价模型的可靠性,为地下空间开发规划提供指导和借鉴。

关键词：地下空间适宜性组合权重数值模拟杭州市

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盾构隧道近侧穿复建桥桩基扰动分析

山西建筑 2024年第2期50卷 151-153,157页

作者：张文涛赵红领王瑞强常友光周威狄杭州市地铁集团有限责任公司浙江杭州310018 中建八局第三建设有限公司江苏南京200000 浙江工业大学土木工程学院浙江杭州310014

随着城市地下轨道交通的快速发展,越来越多的地铁区间隧道下穿城市地表建筑物基础,盾构推进开挖过程对临近桩基产生扰动,可能引起桩基倾斜甚至倒塌,同时盾构隧道开挖过程易引起地表和地层沉降。采用Midas GTS NX 2.2.软件对嘉善地铁区... 详细信息

随着城市地下轨道交通的快速发展,越来越多的地铁区间隧道下穿城市地表建筑物基础,盾构推进开挖过程对临近桩基产生扰动,可能引起桩基倾斜甚至倒塌,同时盾构隧道开挖过程易引起地表和地层沉降。采用Midas GTS NX 2.2.软件对嘉善地铁区间隧道近侧穿复建智果桥桩基进行了仿真分析,获取了掘进过程中临近桩基偏移变化规律、地表沉降规律。研究表明:区间隧道最大沉降位于隧洞中线正上方地表;单侧隧洞开挖引起的桩顶向近隧道方向偏移;双隧道贯通后,区间隧道外侧桩基偏移继续增大,两隧道之间的桩基偏移减小。研究具有理论价值,并对同类工程开挖施工具有参考意义。

关键词：区间隧道桩基近侧穿开挖扰动

Effects of nanoclay addition on the permeability and mechanical properties of ultra high toughness cementitious composites

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Journal of zhejiang university-Science A(Applied Physics & {2.) 2020年第12期21卷 992-1007页

作者： Min-jia WANG He-dong LI Qiang ZENG Qing-fen chang Xiu-shan WANG school of civil {2. and architecture Zhejiang Sci-Tech UniversityHangzhou 310018China College of civil engineering and {2. Zhejiang UniversityHangzhou 310058China Department of Architectural engineering Liaoyuan Vocational Technical CollegeLiaoyuan 136200China

Tuning microstructures by adding nanoparticles is a promising way of improving the performance of cementitious *** this study,nanoclay was introduced to polyvinyl alcohol(PVA)fiber reinforced ultra high toughness cementitious composites(UHTCCs).The mechanical properties,crack patterns,water permeation resistance,and microstructures of UHTCCs with different dosages of nanoclay were *** addition of a proper dosage of nanoclay shows few effects on the compressive strength of UHTCCs,however,the compressive strength is decreased when an excessive amount of nanoclay is *** flexural deformation capacity of UHTCCs is independent of nanoclay dosage,whereas the flexural strength generally decreases with an increasing dosage of *** cracking patterns were observed in the ultra high toughness cementitious composites containing nanoclay(NC-UHTCC)specimens subject to bending tests.A UHTCC with 1%(in weight)nanoclay shows the best water permeation resistance and the lowest water *** in the mechanical properties and the water permeation resistance of UHTCCs containing different dosages of nanoclay could be ascribed to the synthetic effects of filling and heterogeneous nucleation of nanoclay at low dosages and the agglomeration effect of nanoclay at high *** study is to optimize the water permeation resistance of UHTCCs,paving a path for the future application of UHTCCs in the fields of construction,decoration,and repair.

关键词： Nanoclay Water permeability Pore structure Cementitious composites Strain hardening

Response of microbial communities to biochar-amended soils:a critical review

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Biochar 2019年第1期1卷 3-22页

作者： Kumuduni Niroshika Palansooriya James Tsz Fung Wong Yohey Hashimoto Longbin Huang Jörg Rinklebe Scott X.chang Nanthi Bolan Hailong Wang Yong Sik Ok Korea Biochar Research Center O-Jeong Eco-Resilience Institute(OJERI)Division of Environmental Science and Ecological EngineeringKorea UniversitySeoul 02841Republic of Korea Department of civil and Environmental engineering The Hong Kong University of Science and TechnologyHong Kong SARChina Department of Bioapplications and Systems engineering Tokyo University of Agriculture and TechnologyTokyoJapan Environment Centres Sustainable Minerals InstituteThe University of QueenslandBrisbaneQLD 4072Australia Laboratory of Soil-and Groundwater-Management School of Architecture and Civil EngineeringInstitute of Foundation Engineering and Water and-Waste ManagementUniversity of WuppertalPauluskirchstraße 742285 WuppertalGermany Department of Environment Energy and GeoinformaticsSejong UniversitySeoul 05006Republic of Korea Department of Renewable Resources University of AlbertaEdmontonAB T6G 2E3Canada Global Centre for Environmental Remediation University of NewcastleCallaghanNSW 2308Australia school of Environmental and Chemical engineering Foshan UniversityFoshan 528000GuangdongChina Key Laboratory of Soil Contamination Bioremediation of zhejiang Province Zhejiang A&F University

Application of biochar to soils changes soil physicochemical properties and stimulates the activities of soil microorganisms that influence soil quality and plant *** the response of soil microbial communities to biochar amendments is important for better understanding interactions of biochar with soil,as well as ***,the effect of biochar on soil microorganisms has received less attention than its influences on soil physicochemical *** this review,the following key questions are discussed:(i)how does biochar affect soil microbial activities,in particular soil carbon(C)mineralization,nutrient cycling,and enzyme activities?(ii)how do microorganisms respond to biochar amendment in contaminated soils?and(iii)what is the role of biochar as a growth promoter for soil microorganisms?Many studies have demonstrated that biochar-soil application enhances the soil microbial biomass with substantial changes in microbial community *** amendment changes microbial habitats,directly or indirectly affects microbial metabolic activities,and modifies the soil microbial community in terms of their diversity and ***,chemical properties of biochar,(especially pH and nutrient content),and physical properties such as pore size,pore volume,and specific surface area play significant roles in determining the efficacy of biochar on microbial performance as biochar provides suitable habitats for *** mode of action of biochar leading to stimulation of microbial activities is complex and is influenced by the nature of biochar as well as soil conditions.

关键词： Carbon cycling Microbial habitat Microorganisms Nutrient cycling Enzyme activity

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硝酸盐还原菌对给水铸铁管道的腐蚀特性研究

中国给水排水 2023年第7期39卷 43-49页

作者：刘沙沙张卉常珊刘悦凯王文东西安建筑科技大学环境与市政工程学院陕西西安710055 西安建筑科技大学西北水资源与环境生态教育部重点实验室陕西西安710055 浙江省建筑设计研究院浙江杭州310006 西安交通大学人居环境与建筑工程学院陕西西安710049

我国的给水管道仍以铸铁管道为主,铸铁管道在长期使用过程中会产生腐蚀问题,容易造成饮用水二次污染。为此,采用实验室小型反应器,以蒙氏假单胞菌CS01为代表性硝酸盐还原菌,研究了不同硝酸盐初始浓度下细菌CS01对给水铸铁管道的腐蚀作用... 详细信息

我国的给水管道仍以铸铁管道为主,铸铁管道在长期使用过程中会产生腐蚀问题,容易造成饮用水二次污染。为此,采用实验室小型反应器,以蒙氏假单胞菌CS01为代表性硝酸盐还原菌,研究了不同硝酸盐初始浓度下细菌CS01对给水铸铁管道的腐蚀作用,并结合理化分析和失重法探究腐蚀产物特性和腐蚀速率。结果表明,细菌CS01的存在和NO_(3)^(-)-N初始浓度的增大,有利于腐蚀产物中Fe_(3)O_(4)的生成,进而对腐蚀和铁释放起到抑制作用。在NO_(3)^(-)-N初始浓度为2. mg/L条件下,总铁浓度和腐蚀速率均最低,分别为(2.30±1.2.)mg/L、(0.036±0.003)mm/a(第170天),而且NO_(3)^(-)-N消耗量以及NO_(2.^(-)-N和NH_(4)^(+)-N生成量均达到最高;腐蚀产物以α-FeOOH(针状和层状)、CaCO_(3)(粒状)和Fe_(3)O_(4)(球状)为主。

关键词：给水铸铁管道微生物腐蚀硝酸盐还原菌铁释放

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非饱和土中水平入渗方程显式求解

岩土力学 2021年第1期42卷 203-210页

作者：李纪伟林法力韦昌富汪华斌陈盼朱赞成刘子振台州学院建筑工程学院浙江台州318000 中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室湖北武汉430071 华中科技大学土木与水利工程学院湖北武汉430074

在求解非饱和态土中水分入渗问题时,水力函数是体积含水率或者吸力的函数,致使其控制方程呈现出强非线性的特征,进而使得其求解变得十分困难。基于水分在土体介质中流动耗时取极值路径的选择这一假定,引入时间泛函,基于变分法原理将水... 详细信息

在求解非饱和态土中水分入渗问题时,水力函数是体积含水率或者吸力的函数,致使其控制方程呈现出强非线性的特征,进而使得其求解变得十分困难。基于水分在土体介质中流动耗时取极值路径的选择这一假定,引入时间泛函,基于变分法原理将水平入渗问题转化为泛函极值问题。通过求解Euler–Lagrange方程,结合边界条件,得到非线性瞬态水平入渗问题的显式解析解。结合Brooks-Corey型水力函数,显式地求解出该类型非饱和态土的体积含水率发展分布规律。通过计算4种不同类型土体的水平入渗规律,将求解结果与已有结果以及数值结果进行对比,验证了该方法的有效性。结果表明:体积含水率分布与位置距离和湿润峰距离比值呈幂函数关系,指数取决于土-水特征曲线的形状参数;初始条件与边界条件会对体积含水率分布造成不同程度的影响。

关键词：水平入渗变分法 Euler–Lagrange方程 Brooks-Corey模型

箍筋约束超高性能混凝土短柱轴压承载力试验研究

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复合材料学报 2022年第7期39卷 3451-3461页

作者：常亚峰师俊平侯亚鹏陆婷婷西安理工大学土木建筑工程学院西安710048 陕西建研结构工程股份有限公司西安710082 西京学院土木工程学院西安710199

通过对10组配置菱形、十字形复合箍筋的超高性能混凝土(UHPC)短柱和1组未配置钢筋的UHPC短柱进行轴压承载力试验,研究了其破坏过程和破坏形态,分析了箍筋间距、纤维掺量和箍筋形式对其轴向应变-轴向荷载曲线和应力-应变曲线的影响。结... 详细信息

通过对10组配置菱形、十字形复合箍筋的超高性能混凝土(UHPC)短柱和1组未配置钢筋的UHPC短柱进行轴压承载力试验,研究了其破坏过程和破坏形态,分析了箍筋间距、纤维掺量和箍筋形式对其轴向应变-轴向荷载曲线和应力-应变曲线的影响。结果表明,箍筋形式的闭合环数和纤维掺量对UHPC短柱的变形能力有一定程度的改善作用。箍筋间距和纤维掺量对试件轴压承载力及相应轴向峰值应变有显著的影响,箍筋间距对轴向峰值应变的影响更大。相同箍筋间距的菱形复合箍筋(DC)较十字形复合箍筋(CC)试件的峰值荷载有所提高。随着箍筋间距的减小,各试件归一化应力-应变曲线上升段斜率增大,但其下降段却表现出更大差异。纤维掺量和箍筋类形对UHPC试件的应力-应变归一化曲线影响较小。考虑箍筋约束效应及纤维约束效应,建立了复合箍筋约束UHPC短柱轴心受压承载力计算公式;计算结果与试验结果比较,吻合较好。

关键词：菱形复合箍筋十字形复合箍筋约束UHPC 轴压承载力纤维掺量