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Gao-Feng Zhao Qiuyue Yin Adrian R. Russell Yingchun Li Wei Wu Qin Li 《国际地质力学数值与分析法杂志》2019,43(1):166-182
The bonded discrete element model (DEM) is a numerical tool that is becoming widely used when studying fracturing, fragmentation, and failure of solids in various disciplines. However, its abilities to solve elastic problems are usually overlooked. In this work, the main features of the 2D bonded DEM which influence Poisson's ratio and Young's modulus, and accuracy when solving elastic boundary value problems, are investigated. Outputs of numerical simulations using the 2D bonded DEM, the finite element method, a hyper elasticity analysis, and the distinct lattice spring model (DLSM) are compared in the investigation. It is shown that a shear interaction (local) factor and a geometric (global) factor are two essential elements for the 2D bonded DEM to reproduce a full range of Poisson's ratios. It is also found that the 2D bonded DEM might be unable to reproduce the correct displacements for elastic boundary value problems when the represented Poisson's ratio is close to 0.5 or the long-range interaction is considered. In addition, an analytical relationship between the shear stiffness ratio and the Poisson's ratio, derived from a hyper elasticity analysis and applicable to discontinuum-based models, provides good agreement with outputs from the 2D bonded DEM and DLSM. Finally, it is shown that the selection of elastic parameters used the 2D bonded DEM has a significant effect on fracturing and fragment patterns of solids. 相似文献
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利用有限元方法,研究库水载荷产生的应力场及其在断层面上引起的静态库仑破裂应力变化。通过计算发现,库水载荷的加载位置对地震的触发作用有重要的影响:当库水加载于断层正上方或断层上盘时,对正断层型的地震有促进作用,对逆断层型的地震有抑制作用。但是,当库水载荷作用于断层的下盘时,对于倾角较大的正断层与逆断层地震,库水都起抑制作用;而对倾角很小的断层起促进作用,但不会产生很强的水库地震。 相似文献
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本文介绍了几个典型水库地震事件,总结了目前对水库诱发地震的分析方法及其依据,重点从地震发生的时间、空间、强度、活动特征、震源深度5个方面介绍了水库诱发地震的特征,最后简要分析了水库诱发地震的动力学机制,认为通过人为调整库水载荷大小等因素来研究水库地震活动性,对于研究地震触发及地震预报等有重要的社会价值和科学意义。 相似文献
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Lei Gao Qiuyue Zhou Xiangjuan Yu Kexiong Wu Ali H Mahfouz 《Marine Georesources & Geotechnology》2017,35(1):143-148
To study the effect and mechanism of carbon fiber reinforced clay, a series of unconfined compression tests for clay reinforced with carbon fiber have been performed under the conditions of controlled water content and dry density. The carbon fiber is mixed into soil with the quality percentage of 0.01, 0.02, 0.03, 0.05, 0.1, 0.15, 0.25, 0.35, and 0.5%, then a certain quality of water was added in the soil to achieve the optimum soil water content. Ten groups of samples were tested by the unconfined compression experiment. The results showed that the incorporation of carbon fiber elements can effectively improve the unconfined compressive strength and brittle failure mode of soil. The soil is strengthened at the beginning and then weakened with the increased incorporation of carbon fiber, the effect is especially significant when the mix percentage becomes 0.1%. The interaction at the interface between carbon fiber surface and soil matrix is analyzed by using scanning electron microscopy (SEM). It is found that the enhancement mechanisms of carbon fiber reinforced soil are one-dimensional reinforcement of a single carbon fiber thread and three-dimensional reinforcement caused by fiber network respectively. 相似文献
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Influence of canopy and topographic position on soil moisture response to rainfall in a hilly catchment of Three Gorges Reservoir Area,China 总被引：2，自引：0，他引：2
Liu Muxing Wang Qiuyue Guo Li Yi Jun Lin Henry Zhu Qing Fan Bihang Zhang Hailin 《地理学报(英文版)》2020,30(6):949-968
Rainfall provides essential water resource for vegetation growth and acts as driving force for hydrologic process, bedrock weathering and nutrient cycle in the steep hilly catchment. But the effects of rainfall features, vegetation types, topography, and also their interactions on soil water movement and soil moisture dynamics are inadequately quantified. During the coupled wet and dry periods of the year 2018 to 2019, time-series soil moisture was monitored with 5-min interval resolution in a hilly catchment of the Three Gorges Reservoir Area in China. Three hillslopes covered with evergreen forest(EG), secondary deciduous forest mixed with shrubs(SDFS) and deforested pasture(DP) were selected, and two monitoring sites with five detected depths were established at upslope and downslope position, respectively. Several parameters expressing soil moisture response to rainfall event were evaluated, including wetting depth, cumulative rainfall amount and lag time before initial response, maximum increase of soil water storage, and transform ratio of rainwater to soil water. The results indicated that rainfall amount is the dominant rainfall variable controlling soil moisture response to rainfall event. No soil moisture response occurred when rainfall amounts was 8 mm, and all the deepest monitoring sensors detected soil moisture increase when total rainfall amounts was 30 mm. In the wet period, the cumulative rainfall amount to trigger surface soil moisture response in EG-up site was significantly higher than in other five sites. However, no significant difference in cumulative rainfall amount to trigger soil moisture response was observed among all study sites in dry period. Vegetation canopy interception reduced the transform ratio of rainwater to soil water, with a higher reduction in vegetation growth period than in other period. Also, interception of vegetation canopy resulted in a largeraccumulated rainfall amount and a longer lag time for initiating soil moisture response to rainfall. Generally, average cumulative rainfall amount for initiating soil moisture response during dry period of all sites(3.5–5.6 mm) were less than during wet period(5.7–19.7 mm). Forests captured more infiltration water compared with deforested pasture, showing the larger increments of both soil water storage for the whole soil profile and volumetric soil water content at 10 cm depth on two forest slopes. Topography dominated soil subsurface flow, proven by the evidences that less rainfall amount and less time was needed to trigger soil moisture response and also larger accumulated soil water storage increment in downslope site than in corresponding upslope site during heavy rainfall events. 相似文献
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本文研究确定了利用铅锌矿废渣——双旋灰制取工业氯化锌的最佳工艺技术条件。选用1+1盐酸为锌的浸出剂,锌的浸出率高达82%以上。铁、铅、铜、锰、硫等杂质元素采用氯酸钾氧化、锌粉还原和钡盐沉淀等方法、从浸出液中分离除去,将溶液蒸发、浓缩后即得氯化锌产品。经扩大试验验证,工艺流程可行,锌的回收率为80%,产品质量符合国家标准(GB1625—79)规定的二级产品各项指标的要求。 相似文献
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沾化凹陷的渤南洼陷为富油洼陷, 实测超压出现在沙三、四段, 埋深为2 300~4 200 m。综合大量的地压测试、测井和地质资料, 研究了现今超压分布和超压的测井及地震响应, 对单井、剖面超压发育特征和影响超压结构的地质要素进行了深入分析。超压带内泥岩声波时差偏离正常趋势线, 而泥岩密度没有明显偏低的响应。研究表明:渤南洼陷存在3个超压系统, 上超压系统为浅层沙一段发育的弱超压, 沙三段中下部的强超压构成中超压系统的主体, 下超压系统位于沙四段中;砂质质量分数大于20%的沙二段为常压。超压源层、低渗封隔层和断裂构造带3类地质要素控制着超压幅度和超压结构。泥质源岩产生的多相流体是形成超压系统的物质基础;沙一段压实泥岩、沙三中亚段的互层致密砂岩和泥岩、沙四上亚段的膏盐层作为压力系统封隔层, 对超压系统的形成和分布起到控制作用;断裂具有泄压和封堵双重性, 对地层压力和油气层横向分布具有重要影响。利用地震层速度计算得到了渤南洼陷现今大规模超压系统分布特征的整体认识。 相似文献
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Wei Hua Guangzhou Fan Yiwei Zhang Lihua Zhu Xiaohang Wen Yongli Zhang Xin Lai Binyun Wang Mingjun Zhang Yao Hu Qiuyue Wu 《Acta Meteorologica Sinica》2017,31(2):420-430
Trends and uncertainties of surface air temperature over the Tibetan Plateau (TP) are evaluated by using observations at 100 meteorological stations during the period 1951–2013. The sampling error variances of gridded monthly data are estimated for every month and every grid box of data. The gridded data and their sampling error variances are used to calculate TP averages, their trends, and associated uncertainties. It is shown that large sampling error variances dominate northern and western TP, while small variances appear over southern and eastern TP. Every month from January to December has a positive linear trend during the study period. February has the largest trend of 0.34 ± 0.18°C (10 yr)–1, and April the smallest at 0.15 ± 0.11°C (10 yr)–1. The uncertainties decrease steadily with time, implying that they are not large enough to alter the TP warming trend. 相似文献