Hazard-based evaluation model of water inrush disaster sources in karst tunnels and its engineering application     

Shaoshuai Shi  Xiaokun Xie  Lin Bu  Liping Li  Zongqing Zhou 《Environmental Earth Sciences》2018,77(4):141

Water inrush is one of the typical geological hazards that may occur during tunnel construction in a karst area. In this paper, a potential model is established based on attribute mathematics, to assess the risk of water inrush. First, the CaCO₃ content of regional strong karst, thickness of the regional strong karst layer, groundwater recharge area, discharge of groundwater, average temperature characteristic, groundwater level, groundwater cycle characteristic, surface karst morphology, fault structure, fold structure, and monoclinal structure are chosen as evaluation indexes of water inrush based on the principles of scientificity, rationality, operability, and representativeness. Second, the objective weight calculation formula is used to calculate the weights of the evaluation indices, and attribute measurement functions of each evaluation index are constructed to reckon the attribute measurement of a single index and synthetic attribute measurement. Lately, the identification and classification of water and mud inrush hazard in tunnels have been performed using a confidence criterion. In this paper, hazard level is graded as one of four types. The hazard-based assessment methodology is applied to the construction site of the Jigongling Tunnel along the entire Fanba Expressway route, and the findings are compared against the site’s actual situation. The results of the engineering practice show that the evaluation result is consistent with the actual construction situation; thus, the method can provide scientific guidance for tunnel construction units.  相似文献   

The effect of deforestation on the regional temperature in Northeastern China   总被引：1，自引：1，他引：0  

Lingxue Yu  Shuwen Zhang  Junmei Tang  Tingxiang Liu  Kun Bu  Fengqin Yan  Chaobin Yang  Jiuchun Yang 《Theoretical and Applied Climatology》2015,120(3-4):761-771

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雾霾的历史观照与现实关注——基于毒理学史的霾态问题思考          下载免费PDF全文

卜风贤 《气象与减灾研究》2016,39(1):70-73

古代文献中的霾是一种自然异常现象,对霾的认识以及霾与社会的关系体现在历史时期霾类事件的历史记录中,通过梳理霾类事件的历史变化及其内在特征,可将霾与雾霾的关系予以比较清晰的界定:历史时期的霾是一种异常态的自然现象,雾霾仅是其中一种与天气因素相关的霾态问题。而且历史文献中雾霾事件的记录较少,见之于文献的霾类事件更多的是一种霾态问题的泛称。对霾态事件的历史关注并不在于其社会危害性,而是作为异常现象之一种并与其他灾异事件列举对比,以体现五行理论架构下的天人关系。而从雾霾的危害过程看,雾霾的古今差别重点体现在毒性机理方面,雾霾事件的历史研究对毒理科学史的进一步发展具有一定积极意义。  相似文献   

Classification of rivers based on water quality assessment using factor analysis in Taizi River basin, northeast China   总被引：2，自引：0，他引：2  

Jun Wan  Hongmei Bu  Yuan Zhang  Wei Meng 《Environmental Earth Sciences》2013,69(3):909-919

A method for river classification based on water quality assessment (WQA) was introduced using factor analysis (FA) in this paper. Sixty-nine sampling sites and 20 water quality parameters in Taizi River basin were selected for monitoring and analysis. Five factors were determined in FA, denoted as general, hardness, trophic, nitrogen pollution, and physical factors. The total factor scores (TFSs) of the WQA results from all sampling sites were calculated by the eigenvalue and factor score of each factor. The TFSs of 69 sites were interpolated with the measure of inverse distance weighted in the river buffer zone generated by ArcGIS 9.2 software to form a continuous spatial distribution along river channels. All streams were divided into five classes marked “excellent”, “good”, “fair”, “poor”, and “seriously polluted”. The classification result showed that the water quality of Taizi River basin deteriorated gradually from the mountain area to the plain area. Sewage and intensive human activities contributed to the deterioration of water quality since towns and farmland were dotted densely along the river basin.  相似文献   

Abundances of Suprathermal Heavy Ions in CIRs During the Minimum of Solar Cycle 23     

Bučík  R.  Mall  U.  Korth  A.  Mason  G. M. 《Solar physics》2012,281(1):411-422

Solar Physics - In this paper we examine the elemental composition of the 0.1?–?1 MeV?nucleon?1 interplanetary heavy ions from H to Fe in corotating interaction...  相似文献   

A Holocene dust record in arid central Asia inferred from Lake Barkol,northwest China   总被引：1，自引：1，他引：0  

Yanbin Lu  Chengbang An  Jiawu Zhang  Zongli Wang  Shichen Tao  Jiaju Zhao 《Environmental Earth Sciences》2012,65(1):213-220

Grain-size distributions and detrital minerals were investigated for modern dust and for lacustrine sediment in Lake Barkol region, northwest China. Characteristics of the modern dust and lacustrine sediments, principle component analysis, and changes of quartz contents all suggest grain size 45–138 μm in the core sediment is the dust sensitive component. It indicates that high dust flux climate occurred at mid-Holocene (5.5–4.5 cal ka BP), corresponding to the high dust flux record in northwest Pacific and the drought interval of deserts in northwest China during the mid-Holocene. The strong dust activity is in contradiction with the climatic optimum recorded by the lacustrine evidence in Xinjiang. Different responses of the dust source region and watershed to the regional climate may have led to the inconsistency between dust and climate records during the mid-Holocene in arid central Asia.  相似文献   

江雄水库新建大坝渗漏成因分析与处理          下载免费PDF全文

辛建芳  普布  杨俊  司马世华  朱家旺 《探矿工程》2012,39(12):40-44

江雄水库蓄水初期,随着库水位逐渐上升,观测孔内水位高,坝下游陆续出现的渗漏量不断增大,量水堰最大渗漏量达到300 L/s的异常现象,影响大坝安全。通过大坝监测系统、电法探测、连通试验等成果,分析了坝基、绕坝、溢洪道、输水洞等渗漏主因,查找到主要渗流通道,为大坝堵漏处理方案设计提供了决策依据。还提出了安全渗流对保护下游生态有巨大作用的观点。  相似文献   

Study on daily surface evapotranspiration with SEBS in Tibet Autonomous Region简     

ZHUO Ga  LA Ba  PUBU Ciren  LUO Bu 《地理学报(英文版)》2014,24(1):113-128

The estimation of surface evapotranspiration （ET） with satellite dataset is one of the main subjects in the understanding of climate change, disaster monitoring and the circulation of water vapor and energy in Tibet Autonomous Region （TAR）. This research selects satellite images on January 11, April 6, July 31 and October 19 in 2010 as the representative of winter, spring, summer and autumn respectively, estimates the distribution of daily surface ET based on the surface energy balance system （SEBS） along with potential evapotranspiration （PET） and ET derived from Penman-Monteith （P-M） method. The results are obtained as follows. （1） The seasonal distribution of ET and PET basically decreases from the southeast part to the northwest part of TAR. Although ET and PET have similar spatial distributions, there are still some differences to estimate the extreme values especially the maximum value in the middle and southeastern parts of TAR. No matter what kind of methods we adopted, the maximum value of ET and PET always appears in summer, followed by autumn or spring while that in winter is the smallest. （2） In order to better understand the accuracy of SEBS model in the estimation of ET, we compared the ET from SEBS and the ET obtained from P-M method. Results show that the ET from SEBS could estimates the variation trend of actual ET, but it slightly underestimates or overestimates the value of ET as a whole, especially for those areas with thick forest. （3） The spatial distribution of Normalized Difference Vegetation Index （NDVI） exhibits a decreasing trend from the southeast part to the northwest part of TAR which displays remarkable consistency of distributions between ET and vegetation index. ET is well positively related to NDVI, minimum, mean, maximum air temperature and sunshine duration in different seasons while negatively related to precipitation, relative humidity and wind speed in summer.  相似文献   

黄土场地地铁车站振动台试验方案设计与研究     

王玉铃  权登州  柴少波  卜永红  王毅红 《震灾防御技术》2021,16(1):176-185

为得到可靠的试验数据,对黄土场地典型断面地铁车站大型振动台试验方案进行设计与研究。根据试验目的和特点,提出黄土场地与地铁车站动力相互作用模型体系相似设计原则,并基于Bockingham的π定理对模型结构进行相似设计;通过室内试验研究模型材料配合比、力学特性及模型制作技术;采用有限元-无限元耦合数值建模方法,分析黄土场地地铁车站地震响应,基于数值模拟结果对振动台试验中的传感器布设方案进行研究;根据西安及周边地区地震环境特点,确定振动台试验输入地震动与加载方案。研究结果表明,试验模型结构宏观震害与数值模拟结果较吻合。本研究可为黄土场地地铁车站、地铁隧道及地下商业街等地下结构振动台试验方案设计与深入研究提供参考。  相似文献   

双向水平地震动作用对某钢筋混凝土连续梁桥易损性的影响     

刘黎明  徐超  卜春尧  耿飞  温增平 《震灾防御技术》2021,16(4):671-679

以双向水平地震动作为输入,对钢筋混凝土连续箱梁高架桥开展非线性动力时程分析。建立基于双向水平地震动强度参数的桥梁结构易损性曲面,比较单向及双向水平地震动输入下桥梁结构易损性差异,分析双向水平地震动输入下横桥向地震动强度对桥梁整体易损性的影响规律。研究结果表明,双向水平地震动输入下的桥梁结构易损性明显高于单向地震动输入的情况,且随着横桥向输入地震动强度的增加,结构各破坏状态的超越概率明显增大。  相似文献