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111.
地震液化引起的地面大变形对桥梁桩基的影响研究综述 总被引:2,自引:0,他引:2
根据国内外文献资料,主要就地震高烈度区液化引起的地面侧向大变形对桥梁桩基的影响的研究现状进行分析,总结了地面大变形引起的震害情况、液化诱发地面大变形的机理及液化大变形的预测方法、桥梁桩基的震害和液化大变形对桥梁桩基的影响、桥梁桩基抗地面大变形的措施,以及存在问题和研究思路。 相似文献
112.
Jianting Zhu Michael H. Young 《Journal of the American Water Resources Association》2009,45(3):641-653
Abstract: We proposed a step‐by‐step approach to quantify the sensitivity of ground‐water discharge by evapotranspiration (ET) to three categories of independent input variables. To illustrate the approach, we adopt a basic ground‐water discharge estimation model, in which the volume of ground water lost to ET was computed as the product of the ground‐water discharge rate and the associated area. The ground‐water discharge rate was assumed to equal the ET rate minus local precipitation. The objective of this study is to outline a step‐by‐step procedure to quantify the contributions from individual independent variable uncertainties to the uncertainty of total ground‐water discharge estimates; the independent variables include ET rates of individual ET units, areas associated with the ET units, and precipitation in each subbasin. The specific goal is to guide future characterization efforts by better targeting data collection for those variables most responsible for uncertainty in ground‐water discharge estimates. The influential independent variables to be included in the sensitivity analysis are first selected based on the physical characteristics and model structure. Both regression coefficients and standardized regression coefficients for the selected independent variables are calculated using the results from sampling‐based Monte Carlo simulations. Results illustrate that, while as many as 630 independent variables potentially contribute to the calculation of the total annual ground‐water discharge for the case study area, a selection of seven independent variables could be used to develop an accurate regression model, accounting for more than 96% of the total variance in ground‐water discharge. Results indicate that the variability of ET rate for moderately dense desert shrubland contributes to about 75% of the variance in the total ground‐water discharge estimates. These results point to a need to better quantify ET rates for moderately dense shrubland to reduce overall uncertainty in estimates of ground‐water discharge. While the approach proposed here uses a basic ground‐water discharge model taken from an earlier study, the procedure of quantifying uncertainty and sensitivity can be generalized to handle other types of environmental models involving large numbers of independent variables. 相似文献
113.
本文通过对岷江干流(成都段)地表水和地下水的综合研究,分别提出了地表水污染防治对策和地下水水质防护措施,划分出了地表水防治不同时期的目标以及地下水开采管理目标。 相似文献
114.
115.
通过对宁波台地倾斜近几年来观测资料的分析,发现其在皎口几组地震事件前有不同程度的异常反应。在分量图上,震前出现了短临期前兆异常反应特征,并且有异常时间越长,幅度越大,地震震级就越高的特点。此外还对异常出现的成因作了探讨 相似文献
116.
污染天气分型研究对空气质量预报、污染源总量控制等具有重要的意义。基于2013年1月~2014年12月高空及地面天气形势划分了成都市的天气类型并探讨各天气类型下的空气质量状况及其污染天气特征,以期为空气质量预报和预警提供依据。结果表明,空气污染过程中,500 hpa环流形势主要有两槽一脊型、一槽一脊型、纬向型、槽脊同位相型等,其中两槽一脊型和槽脊同位相型控制下的空气质量最差。发生空气污染时,地面环流形势可分为高压型、高压后部型、高压底部型、低压型、低压顶部型、低压前部型、低压底部型、鞍型场型、冷锋前部型和均压场型,其中高压型、高压底部型、高压后部型控制下的空气质量最差。 相似文献
117.
Du YB Lee CT Christina D Belfer ML Betancourt TS O'Rourke EJ Palfrey JS 《Disasters》2012,36(3):495-513
The tsunami that struck South-east Asia on 26 December 2004 left more than 500,000 people in Aceh, Indonesia, homeless and displaced to temporary barracks and other communities. This study examines the associations between prolonged habitation in barracks and the nature of fears reported by school-age children and adolescents. In mid-2007, 30 months after the tsunami, the authors interviewed 155 child and parent dyads. Logistic regression analysis was used to compare the fears reported by children and adolescents living in barracks with those reported by their peers who were living in villages. After adjusting for demographic factors and tsunami exposure, the data reveals that children and adolescents living in barracks were three times more likely than those living in villages to report tsunami-related fears. The study demonstrates that continued residence in barracks 30 months after the tsunami is associated with higher rates of reporting tsunami-related fears, suggesting that barracks habitation has had a significant impact on the psychological experience of children and adolescents since the tsunami. 相似文献
118.
在汶川8.0级大地震中,国家数字强震动台网布设在龙门山断裂带及其周围地区的50多个台站获得了大于100 Gal的加速度记录。选取其中断层附近11个台站的加速度记录,分别进行了地震反应谱分析和基于正交化HHT法的能量分布特征分析,通过对竖向与水平向加速度峰值比、竖向与水平向加速度反应谱比值,以及能量分布和峰值系数的分析与比较,探讨了汶川地震的近场地震动特征。 相似文献
119.
Changes in the Carabid Fauna (Coleoptera, Carabidae) of Meadow Steppes during the Past Decades 总被引:1,自引:0,他引:1
T. E. Grechanichenko 《Russian Journal of Ecology》2001,32(2):117-121
Basic trends in the structural dynamics of the meadow-steppe carabid fauna over the period from 1970 to 1997 have been analyzed. Data on changes in the abundance and composition of dominant species are reported. Transformation of carabidocenoses is mainly accounted for by an increased humidity of the climate and the related mesophytization of forest–steppe ecosystems. 相似文献
120.
Wei‐Han Liu Miguel A. Medina Wayne Thomann Warren T. Piver Timothy L. Jacobs 《Journal of the American Water Resources Association》2000,36(6):1335-1348
ABSTRACT: Using a genetic algorithm (GA), optimal intermittent pumping schedules were established to simulate pump‐and‐treat remediation of a contaminated aquifer with known hydraulic limitations and a water miscible contaminant, located within the Duke Forest in Durham, North Carolina. The objectives of the optimization model were to minimize total costs, minimize health risks, and maximize the amount of contaminant removed from the aquifer. Stochastic ground water and contaminant transport models were required to provide estimates of contaminant concentrations at pumping wells. Optimization model simulations defined a tradeoff curve between the pumping cost and the amount of contaminant extracted from the aquifer. For this specific aquifer/miscible contaminant combination, the model simulations indicated that pump‐and‐treat remediation using intermittent pumping schedules for each pumping well produced significant reductions in predicted contaminant concentrations and associated health risks at a reasonable cost, after a remediation time of two years. 相似文献