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深开挖降水之可靠度分析
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作者 赵晓周 秦中天 苏鼎钧 《长江科学院院报》 CSCD 北大核心 2011年第1期71-77,共7页
在台北盆地大型深开挖工程中,抽降开挖面下方景美砾石层地下水头为维持开挖区之稳定性及减缓上举破坏之风险常采用的措施。通常,配合大型深开挖工程抽降景美砾石层地下水时,因抽水量大、抽水时间长、且须额外之配电及排水设施,因此相关... 在台北盆地大型深开挖工程中,抽降开挖面下方景美砾石层地下水头为维持开挖区之稳定性及减缓上举破坏之风险常采用的措施。通常,配合大型深开挖工程抽降景美砾石层地下水时,因抽水量大、抽水时间长、且须额外之配电及排水设施,因此相关工程费用相当显著。景美砾石层系盆地东南侧古新店溪搬运之砾石泥砂沉积后所形成之扇状砾石层,上覆数十米厚,由后续之湖相沉积所形成之砂泥质松山层。受到厚度分布及材料粒径组成之差异性影响,景美砾石层在盆地不同位置处水理系数之差异性极大。受此不确定性之影响,以传统的决定性方法欲准确地推估开挖稳定所需地下水头之泄降量并不容易。由对台北盆地某深开挖基地上举稳定之可靠度分析结果得知,在不同之不确定条件下,即使安全因数之计算结果大致相同,但由于系统之可靠度会随不确定条件而改变,因此即使设计结果符合规范亦不能保证系统之可靠度是可以接受的。此外,敏感度分析结果显示,在地层厚度、土壤密度、水头高、导水系数及贮水系数等分析参数中,景美砾石层导水系数及水头高度的不确定性对设计结果的影响最为显着,若能降低这些参数的不确定性,将可明显提高设计结果的可靠度。 展开更多
关键词 可靠度分析 蒙地卡罗仿真 景美砾石层 深开挖 地下水抽降
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Land subsidence induced by groundwater extraction and building damage level assessment—a case study of Datun, China 被引量:4
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作者 FENG Qi-yan LIU Gang-jun +3 位作者 MENG Lei FU Er-jiang ZHANG Hai-rong ZHANG Ke-fei 《Journal of China University of Mining and Technology》 EI 2008年第4期556-560,共5页
As in many parts of the world, long-term excessive extraction of groundwater has caused significant land-surface sub- sidence in the residential areas of Datun coal mining district in East China. The recorded maximum ... As in many parts of the world, long-term excessive extraction of groundwater has caused significant land-surface sub- sidence in the residential areas of Datun coal mining district in East China. The recorded maximum level of subsidence in the area since 1976 to 2006 is 863 mm, and the area with an accumulative subsidence more than 200 mm has reached 33.1 km2 by the end of 2006. Over ten cases of building crack due to ground subsidence have already been observed. Spatial variation in ground subsi- dence often leads to a corresponding pattern of ground deformation. Buildings and underground infrastructures have been under a higher risk of damage in locations with greater differential ground deformation. Governmental guideline in China classifies build- ing damages into four different levels, based on the observable measures such as the width of wall crack, the degree of door and window deformation, the degree of wall inclination and the degree of structural destruction. Building damage level (BDL) is esti- mated by means of ground deformation analysis in terms of variations in slope gradient and curvature. Ground deformation analysis in terms of variations in slope gradient has shown that the areas of BDL III and BDL II sites account for about 0.013 km2 and 0.284 km2 respectively in 2006, and the predicted areas of BDL (define this first) III and II sites will be about 0.029 km2 and 0.423 km2 respectively by 2010. The situation is getting worse as subsidence continues. That calls for effective strategies for subsidence miti- gation and damage reduction, in terms of sustainable groundwater extraction, enhanced monitoring and the establishment of early warning systems. 展开更多
关键词 land subsidence groundwater extraction ground deformation slope gradient building damage level Datun China
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