煤矿塌陷区复垦土壤环境质量评价   总被引：1，自引：0，他引：1  

马力阳  朱江  周俊  马来  李涛  杨洪波 《安徽地质》2014,(1):70-74

通过对煤矿塌陷区复垦土壤采样测试,研究土壤中重金属铜、锌、镉、汞、砷、铅、铬的含量对土壤环境的影响。研究结果表明:按单因子污染指数法和内梅罗综合污染指数法,结合国家土壤环境质量标准对复垦土壤的质量进行评价:研究区内土壤环境质量良好,基本上可以达到国家土壤环境质量二级标准,安全清洁级别;参照《无公害食品蔬菜产地环境条件标准》、《绿色食品产地环境质量标准》和《有机农业生产基地环境质量标准》,对复垦土壤的农用环境进行评价:研究区内土壤全部达到绿色食品产地环境质量标准,如果选择合理的修复方法,对部分有轻微污染的土壤进行,则可以达到有机农业生产基地环境质量标准;以潜在生态危害指数RI分析,复垦区内土壤重金属潜在生态危害指数相对较低,复垦区农业生产具有良好的发展前景。  相似文献   

群孔抽水试验与同位素分析在煤矿水文地质勘查中的应用     

来永伟  李本军  王志奇  齐荣贵 《中国煤炭地质》2014,(1):39-42

田庄煤矿主采煤层为石炭系太原组16上及17煤层,威胁煤层开采的地下水水源主要为十下灰、十三、十四灰和奥灰含水层。其中十三、十四灰含水层水力联系密切,可按同一含水层看待。十下灰岩水为16上煤的直接充水水源,十三、十四灰灰岩水和奥灰灰岩水为16上及17煤层的底板间接充水水源,在构造地段有可能转化为直接充水水源。在研究煤矿群孔放水试验的基础上,全面分析了氢氧同位素资料,结果表明井田内十下灰和奥灰含水层有各自的补、径、排系统,正常情况下水力联系较弱;十三、十四灰含水层与十下灰和奥灰含水层均发生着水力联系,在采掘及导水断层的影响下,其含水层间地下水联系变得更加密切。两种研究的结论基本一致,增加了成果的科学性和可信性。  相似文献   

Experimental study,numerical modeling of and axial prediction approach to base grouted drilled shafts in cohesionless soils     

Sudheesh Thiyyakkandi  Michael McVay  David Bloomquist  Peter Lai 《Acta Geotechnica》2014,9(3):439-454

The pressure grouting of drilled shaft tips has become popular worldwide due to its effectiveness in mobilizing a larger portion of the available tip resistance under service displacements. This paper presents experimental and numerical studies on the load transfer mechanism and factors controlling the axial response of base grouted drilled shafts in cohesionless soils. The study found that the increased axial capacity of grout-tipped drilled shafts under service loads and displacements depended mainly on preloading effects and the increased tip area provided by the grouting process. A simple prediction approach for estimating the tip capacity of grouted shafts utilizing cone penetration resistance was suggested based on the results of the study. The validity of the proposed approach was verified by the analysis of full-scale case studies of grouted shafts reported in the literature.  相似文献   

Coupling typhoon rainfall forecasting with overland-flow modeling for early warning of inundation   总被引：1，自引：0，他引：1  

Tsung-Yi Pan  Lung-Yao Chang  Jihn-Sung Lai  Hsiang-Kuan Chang  Cheng-Shang Lee  Yih-Chi Tan 《Natural Hazards》2014,70(3):1763-1793

Taiwan suffers from an average of three or four typhoons annually, and the inundation caused by the heavy precipitation that is associated with typhoons frequently occurs in lowlands and floodplains. Potential inundation maps have been widely used as references to set up non-structural strategies for mitigating flood hazards. However, spatiotemporal rainfall distributions must be addressed to improve the accuracy of inundation forecasting for emergency response operations. This study presents a system for 24-h-ahead early warning of inundation, by coupling the forecasting of typhoon rainfall with the modeling of overland flow. A typhoon rainfall climatology model (TRCM) is introduced to forecast dynamically the spatiotemporal rainfall distribution based on typhoon tracks. The systematic scheme for early warning of inundation based on the spatiotemporal downscaling of rainfall and 2D overland-flow modeling yields not only the extent of inundation, but also the time to maximum inundation depth. The scheme is superior to traditional early warning method referring to the maximum extent and depth of inundation determined from conditional uniform rainfall. Analytical results show that coupling TRCM with an overland-flow model yields satisfactory inundation hydrographs for warning of the extent and peak time of inundation. This study also shows that the accuracy of forecasting spatiotemporal rainfall patterns determines the performance of inundation forecasting, which is critical to emergency response operations.  相似文献   

On improving tropical cyclone track forecasts using a scale-selective data assimilation approach: a case study     

Zhijuan Lai  Sai Hao  Shiqiu Peng  Bei Liu  Xiangqian Gu  Yu-Kun Qian 《Natural Hazards》2014,73(3):1353-1368

A dynamical downscaling approach based on scale-selective data assimilation (SSDA) is applied to tropical cyclone (TC) track forecasts. The results from a case study of super Typhoon Megi (2010) show that the SSDA approach is very effective in improving the TC track forecasts by fitting the large-scale wind field from the regional model to that from the global forecast system (GFS) forecasts while allowing the small-scale circulation to develop freely in the regional model. A comparison to the conventional spectral-nudging four-dimensional data assimilation (FDDA) indicates that the SSDA approach outperforms the FDDA in TC track forecasts because the former allows the small-scale features in a regional model to develop more freely than the latter due to different techniques used. In addition, a number of numerical experiments are performed to investigate the sensitivity of SSDA’s effect in TC track forecasts to some parameters in SSDA, including the cutoff wave number, the vertical layers of the atmosphere being adjusted, and the interval of SSDA implementation. The results show that the improvements are sensitive in different extent to the above three parameters.  相似文献   

Optical dating of sand wedges and ice‐wedge casts from Qinghai Lake area on the northeastern Qinghai‐Tibetan Plateau and its palaeoenvironmental implications     

Xiang‐Jun Liu  Zhong‐Ping Lai 《Boreas: An International Journal of Quaternary Research》2013,42(2):333-341

Sand wedges and ice‐wedge casts in the Qinghai Lake area on the northeastern Qinghai‐Tibetan Plateau (QTP) occur within alluvial gravel or river terrace deposits. In this study, we report the results of quartz Optically Stimulated Luminescence (OSL) dating of the infill of five relict sand wedges and one ice‐wedge cast. Combining our dating results with previously published luminescence ages of permafrost wedges in the Qinghai Lake area, we show that sand/ice wedges formed at c. 62 ka, c. 45 ka and between 30 and 15 ka, and that the mean annual air temperature (MAAT) was depressed by at least ～3°C relative to present during the sand/ice‐wedge formation periods. This new work is partially corroborated by post‐LGM proxy records from lakes and aeolian deposits reported from the northeastern QTP. It also significantly extends the palaeoenvironmental record in the region in the period before the LGM, when other proxy records are rare, allowing a better understanding of the palaeoenvironmental conditions on the northeastern QTP.  相似文献   

The yield of ionization in critical ionization velocity space experiments     

Shu T. Lai  William J. Mcneil  Edmond Murad 《Astrophysics and Space Science》1996,235(2):269-287

We compare the conditions in laboratory and space critical ionization velocity (CIV) experiments. One significant difference that comes to light is the rapid expansion of the neutral cloud in space experiments, which does not take place in the laboratory. This has important ramifications for the ultimate ionization yield if there is a time delay in the ignition of the CIV discharge. We find that a simple kinetic model implies that the delay time of CIV ignition is a critical factor in determining the ultimate yield of the experiment. Although the delay time is difficult to calculate precisely, we provide some estimates that predict low CIV yield for typical space experimental geometries, densities and expansion rates. We examine the possibility of the variation of experimental conditions to maximize yield, but find that natural limitations in the design of space experiments may lead to low yields in the best of circumstances. This implies that experiments to date neither prove nor disprove the relevance of the CIV process to cosmology.  相似文献   

震害现场紧急卫星通讯系统的研究和建设     

张建华  赖锡安  吴亚明  陈文明 《大地测量与地球动力学》1993,(4)

本文研究了应用VSAT技术建立大震现场紧急通讯系统的设计和实施方案,规定了该系统应实现的功能。在此基础上,提出了建立我国未来陆地地震救灾移动卫星通讯计划,并对一些关键技术和为移动用户可能提供的通讯业务进行了讨论。  相似文献   

A Comparison Study on the δD Value of Polycyclic Aromatic Hydrocarbons in Hydrous Pyrolysate of Herbaceous Peat with Different Water Medium     

DUAN Yi  WU Yingzhong  XING Lantian  WU Yingqin  ZHAO Yang  LI Zhongping  MA Lanhu  DUAN Mingchen 《《地质学报》英文版》2023,97(6):1734-1743

To investigate the influence of diagenetic water media on the hydrogen isotopes of individual sedimentary aromatic compounds, a series of hydrous pyrolyses were conducted on herbaceous peat. Polycyclic aromatic hydrocarbons (PAHs) in hydrous pyrolysed samples and their hydrogen isotopic composition characteristics were studied. The aqueous medium demonstrated a significant influence on the hydrogen isotopic composition of the individual PAHs generated during pyrolysis. The results showed that the PAHs formed after pyrolysis in the presence of a saltwater medium with high δD value from a salt lake had a heavy hydrogen isotopic composition. The PAHs formed after pyrolysis in the presence of a fresh water medium with low δD value from a swamp had a light hydrogen isotopic composition. The difference in the average PAH δD value between the two hydrous experiments varied from –174‰ to –109‰, suggesting that the hydrogen isotopic composition of individual sedimentary PAHs can reflect the source of the diagenetic water medium. In addition, a comparative study found that the hydrogen isotopes of PAHs were superior to those of n-alkanes in the same sample for diagenetic water indications. The results indicated that the exchange of water-derived inorganic hydrogen and organic hydrogen was more intensive in freshwater experiments than in saltwater experiments. With an increase in the simulation temperature, the average δD value of PAHs generated in the hydrous simulation experiments showed an increasing trend, reflecting that the δD value of sedimentary PAHs formed with the participation of diagenetic water media was still closely related to the thermal maturity of organic matter. Comparative studies showed that the δD values of different types of organic compounds produced by hydrous pyrolysis of peat were in the order, PAHs > n-alkanes > methane.  相似文献   

晚更新世以来珠江三角洲钻孔年代及沉积演化     

林鹏辉  李宏卫  詹伟琪  凌恳  宋盈瑾  徐晓琳  赖忠平 《地质论评》2023,69(Z1):333-335

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