南宁膨胀土持水性能的温度效应及微观机制     

曾召田  崔哲旗  孙德安  姚志  潘斌 《岩土力学》2023,(8):2177-2185

采用蒸汽平衡法测定了4种温度(T=5、25、40、60℃)条件下Whatman No.42滤纸的率定曲线,建立了考虑温度影响的双线性率定曲线方程,发现滤纸的持水性能随温度升高而降低,且温度对率定曲线高吸力段滤纸持水性能的影响要弱于低吸力段。在此基础上,以南宁膨胀土为研究对象,使用滤纸法测定了不同温度作用下膨胀土试样的土-水特征曲线。试验结果表明,随着温度的升高,膨胀土持水性能下降,但温度的影响幅度会随着吸力的增大而减弱,当基质吸力达到40MPa时,不同温度下试样的体积含水率并没有明显变化,即此时温度对膨胀土的持水性能变化几乎无影响。为解释上述宏观现象,选取部分试样进行了压汞试验和吸附结合水试验,并根据试验结果从土体中各相及各相界面相互耦合作用的物理机制角度阐述了南宁膨胀土持水性能的温度效应及微观机制。  相似文献   

江苏某材料厂周边农田土壤钼污染特征及农作物健康风险评价（84）     

范健  黄顺生  崔晓丹 《江苏地质》2023,47(1):84-90

为了解江苏某材料厂金属冶炼活动引发的重金属污染风险,采集周围农田土壤、小麦和水稻籽实样品,确定Mo含量及其在土壤中的形态,采用地质累积指数和富集因子指标评价土壤中钼的污染风险,采用健康风险指数评价小麦、稻米中Mo的健康风险。结果表明,农田土壤中Mo含量在0.50～63.2 mg/kg之间,其平均值5.70 mg/kg远高于全省平均值0.65 mg/kg,表层土壤出现了中度—高度富集,近70%的样点受到不同程度的钼污染,污染范围距该厂300 m,污染深度>1.5 m。土壤中的Mo具有较高的生物有效性,在小麦、水稻籽实中显著富集,主要与土壤具有较高的全Mo含量以及土壤呈碱性有关。基于EPA的健康风险评估方法,食用当地稻米、小麦会产生较大的健康风险。  相似文献   

Gas migration behavior in saturated bentonite under flexible conditions with consideration of temperature effects     

Cui  Lin-Yong  Ye  Wei-Min  Wang  Qiong  Chen  Yong-Gui  Chen  Bao 《Acta Geotechnica》2023,18(2):971-984

Acta Geotechnica - Investigation of thermal effects on gas migration behavior in saturated bentonite materials is of great significance for the assessment of long-term safety and performance...  相似文献   

胶州湾沉积物中石油降解菌的降解能力及多样性研究     

高伟  高祥兴  米铁柱  韩彬  张毅然  李馨子  尹晓斐  孙承君  李倩  崔志松  栾晓  于志刚  郑立 《海洋学报(英文版)》2019,38(6):54-64

2013年青岛输油管道爆炸，大量石油污染了附近海岸。课题组采集了污染的沉积物样品，以原油为唯一碳源和能源，富集了四个石油降解菌群。生物多样性和群落分析表明，Luteibacter、Parvibaculum 和属于食烷菌科的一个属是降解菌群的主要优势菌，都属于变形菌门。从石油降解菌群中分离筛选，获得了9株具有不同16S rRNA基因序列的降解菌，分别属于8个属。重量法测定降解菌的石油降解率，其中5株的石油降解率大于30%。GC-MS分析结果表明，石油降解菌多倾向于降解烷烃，对多环芳烃的降解能力较差，其中5株细菌的烷烃降解率较大，仅1株菌D2对多环芳烃的降解率较大，其降解率在34.9%到77.5%。通过对高通量数据的分析，表明食烷菌属是菌群A和菌群E的主要降解菌群，其中筛选获得的菌株E4可能是菌群E的一株优势降解菌。本研究所筛选菌株证明了其石油降解潜力，为油污染海滩生物修复提供了菌株资源。  相似文献   

Trends and risk evolution of drought disasters in Tibet Region,China     

Chen  Qiong  Liu  Fenggui  Chen  Ruijie  Zhao  Zhilong  Zhang  Yili  Cui  Peng  Zheng  Du 《地理学报(英文版)》2019,29(11):1859-1875

Journal of Geographical Sciences - The risk posed by natural disasters can be largely reflected by hazard and vulnerability. The analysis of long-term hazard series can reveal the mechanisms by...  相似文献   

A biodiversity evaluation framework for restoration of aquatic macrophyte communities in shallow lakes driven by hydrological process management     

Shuhan Li  Tao Sun  Wei Yang  Baoshan Cui  Xinan Yin 《水文研究》2021,35(1):e13983

Macrophyte community diversity and composition respond to ecosystem conservation and local environmental factors. In this study, we developed a multidimensional diversity framework for macrophyte communities, including the taxonomic and functional alpha and beta diversity. We used the framework to explore the relationships among water level regimes and these diversity parameters in a case study of China's Baiyangdian Lake. Analysis of indicators of hydrologic alteration divided the water level from 1959 to 2019 into four regimes (dry, <6.42 m; low, 6.42–7.23 m; medium, 7.23–8.19 m; high, >8.19 m). Alpha and beta diversity were significantly higher in the medium regime than in the low and high regimes. Redundancy analysis indicated that the maximum water depth significantly affected taxonomic alpha diversity, and total nitrogen (TN) and chemical oxygen demand (COD) concentration significantly affected functional alpha diversity, respectively. Mantel tests showed that TN, Secchi depth (SD), and water depth in the high water level regime significantly increased the total beta diversity and turnover components. TN was the main factor that increased total taxonomic beta diversity. Water level regime mainly influenced interspecific relationships by changing the TN and COD concentration. The water level should be maintained between the medium and high water level regimes to promote restoration of the macrophyte community and improve ecosystem stability. The biodiversity evaluation framework would provide a deeper insight into the hydrological process management for restoration of aquatic macrophyte communities in shallow lakes.  相似文献   

Quantifying the impacts of climate change and land use on hydrological processes: A comparison between mountain and lowland agricultural watersheds     

Zhen Cui  Jiacong Huang  Feng Tian  Junfeng Gao  Xuesong Wang  Jun Li 《水文研究》2020,34(26):5370-5383

Mountain and lowland watersheds are two distinct geographical units with considerably different hydrological processes. Understanding their hydrological processes in the context of future climate change and land use scenarios is important for water resource management. This study investigated hydrological processes and their driving factors and eco-hydrological impacts for these two geographical units in the Xitiaoxi watershed, East China, and quantified their differences through hydrological modelling. Hydrological processes in 24 mountain watersheds and 143 lowland watersheds were simulated based on a raster-based Xin'anjiang model and a Nitrogen Dynamic Polder (NDP) model, respectively. These two models were calibrated and validated with an acceptable performance (Nash-Sutcliffe efficiency coefficients of 0.81 and 0.50, respectively) for simulating discharge for mountain watersheds and water level for lowland watersheds. Then, an Indicators of Hydrological Alteration (IHA) model was used to help quantify the alterations to the hydrological process and their resulting eco-hydrological impacts. Based on the validated models, scenario analysis was conducted to evaluate the impacts of climate and land use changes on the hydrological processes. The simulation results revealed that (a) climate change would cause a larger increase in annual runoff than that under land use scenario in the mountain watersheds, with variations of 19.9 and 10.5% for the 2050s, respectively. (b) Land use change was more responsible for the streamflow increment than climate change in the lowland watersheds, causing an annual runoff to increase by 27.4 and 16.2% for the 2050s, respectively. (c) Land use can enhance the response of streamflow to the climatic variation. (d) The above-mentioned hydrological variations were notable in flood and dry season in the mountain watersheds, and they were significant in rice season in the lowland watersheds. (e) Their resulting degradation of ecological diversity was more susceptible to future climate change in the two watersheds. This study demonstrated that mountain and lowland watersheds showed distinct differences in hydrological processes and their responses to climate and land use changes.  相似文献   

Erratum to: Sudden surface collapse disasters caused by shallow partial mining in Datong coalfield,China     

Ximin Cui  Yongge Gao  Debao Yuan 《Natural Hazards》2015,75(1):1005-1005

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Assessment of flow paths and confluences for saltwater intrusion in a deltaic river network          下载免费PDF全文

Baoshan Cui  Xiaojing Shao  Zhiming Zhang 《水文研究》2015,29(20):4549-4558

Saltwater intrusion is a serious issue in estuarine deltas all over the world due to rapid urban sprawl and water shortage. Therefore, detecting the major flow paths or locations at risk of saltwater intrusion in estuarine ecosystems is important for mitigating saltwater intrusion. In this paper, we introduce a centrality index, the betweenness centrality (BC), to address this problem. Using the BC as the weighted attribute of the river network, we identify the critical confluences for saltwater intrusion and detect the preferential flow paths for saltwater intrusion through the least‐cost‐path algorithm from a graph theory approach. Moreover, we analyse the responses of the BC values of confluences calculated in the river network to salinity. Our results show that the major flow paths and critical confluences for saltwater intrusion in a deltaic river network can be represented by the least cost paths and the BC values of confluences, respectively. In addition, a significant positive correlation between the BC values of confluences and salinity is determined in the Pearl River Delta. Changes in the salinity can produce significant variation in the BC values of confluences. Therefore, freshwater can be diverted into these major flow paths and critical confluences to improve river network management under saltwater intrusion. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Groundwater Microbial Communities Along a Generalized Flowpath in Nomhon Area,Qaidam Basin,China          下载免费PDF全文

Yizhi Sheng  Guangcai Wang  Dan Zhao  Chunbo Hao  Chenglong Liu  Linfeng Cui  Ge Zhang 《Ground water》2018,56(5):719-731

Spatial distribution (horizonal and vertical) of groundwater microbial communities and the hydrogeochemistry in confined aquifers were studied approximately along the groundwater flow path from coteau to plain in the Nomhon area, Qinghai‐Tibet plateau, China. The confined groundwater samples at different depths and locations were collected in three boreholes through a hydrogeological section in this arid and semi‐arid area. The phylogenetic analysis of 16S rRNA genes and multivariate statistical analysis were used to elucidate similarities and differences between groundwater microbial communities and hydrogeochemical properties. The integrated isotopic geochemical measurements were applied to estimate the source and recharge characteristics of groundwater. The results showed that groundwater varied from fresh to saline water, and modern water to ancient water following the flowpath. The recharge characteristics of the saline water was distinct with that of fresh water. Cell abundance did not vary greatly along the hydrogeochemical zonality; however, dissimilarities in habitat‐based microbial community structures were evident, changing from Betaproteobacteria in the apex of alluvial fan to Gammaproteobacteria and then to Epsilonproteobacteria in the core of the basin (alluvial‐lacustrine plain). Rhodoferax, Hydrogenophaga, Pseudomonas, and bacterium isolated from similar habitats unevenly thrived in the spatially distinct fresh water environments, while Sulfurimonas dominanted in the saline water environment. The microbial communities presented likely reflected to the hydrogeochemical similarities and zonalities along groundwater flowpath.  相似文献