A study on one‐dimensional consolidation of layered structured soils          下载免费PDF全文

Kang‐He Xie  Chang‐Qing Xia  Ran An  Hong‐Wei Ying  Hao Wu 《国际地质力学数值与分析法杂志》2016,40(7):1081-1098

The governing equations for one‐dimensional consolidation of layered structured soils under time‐dependent loading are established. Using simplified k‐σ′ and m_v‐σ′ models, n‐layered structured soils are transformed into (n + 1) or (n + 2)‐layered soils in which the thickness of upper and lower layers are gradually changing. The approximate solutions for the governing equations are then obtained under two types of boundary conditions, and the computer program is developed. Based on the solutions and computer program, the consolidation behavior of layered structured soils with soft interlayer is studied. It is shown that the permeability and compressibility of the soft interlayer have the greatest influences on the rate of settlement and rate of the dissipation of excess pore water pressure. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Optimized reservoir operation to balance human and riverine ecosystem needs: model development,and a case study for the Tanghe reservoir,Tang river basin,China     

Xinan Yin  Zhifeng Yang  Wei Yang  Yanwei Zhao  He Chen 《水文研究》2010,24(4):461-471

Reservoirs impose many negative impacts on riverine ecosystems. To balance human and ecosystem needs, we propose a reservoir operation method that combines reservoir operating rule curves with the regulated minimum water release policy to meet the environmental flow requirements of riverine ecosystems. Based on the relative positions of the reservoir and the water intakes, we consider three scenarios: water used for human needs (including industrial, domestic and agricultural) is directly withdrawn from (1) the reservoir; (2) both reservoirs and downstream river channels and (3) downstream river. The proposed method offers two advantages over traditional methods: First, it can be applied to finding the optimal reservoir operating rule curves with the consideration of environmental flow requirement, which is beneficial to the sustainable water uses. Second, it avoids a problem with traditional approaches, which prescribe the minimum environmental flow requirements as the regulated minimum environmental flow releases from reservoirs, implicitly giving lower priority to the riverine ecosystem. Our method instead determines the optimal regulated minimum releases of water to sustain environmental flows while more effectively balancing human and ecosystem needs. To demonstrate practical use of the model, we present a case study for operation of the Tanghe reservoir in China's Tang river basin for the three above‐mentioned scenarios. The results demonstrate that this approach will help the reservoir's managers satisfy both human and environmental requirements. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Comparative analysis of relationships between NLDAS‐2 forcings and model outputs     

Youlong Xia  Mike Ek  Helin Wei  Jesse Meng 《水文研究》2012,26(3):467-474

This study reports results from an analysis of the relationship between atmospheric forcing and model‐simulated water and energy fluxes for the North American Land Data Assimilation System Project Phase 2 (NLDAS‐2). The relationships between mean monthly precipitation and total runoff are stronger in the Sacramento (SAC) and variable infiltration capacity (VIC) models, which grew out of the hydrological community, than in the Noah and Mosaic models, which grew out of the soil‐vegetation‐atmosphere transfer (SVAT) community. The reverse is true for the relationship between mean monthly precipitation and evapotranspiration. In addition, surface energy fluxes in VIC are less sensitive to model forcing (except for air temperature) than those in the Noah and Mosaic model. Notwithstanding these general conclusions, the relationships between forcings and model‐simulated water and energy fluxes for all models vary for different seasons, variables, and regions. These findings will ultimately inspire a combination of SVAT‐type model energy components with hydrological model water components to develop a SVAT‐hydrology model to improve both evapotranspiration and total runoff simulations. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

黄铁矿叠层石丘堆式沉积与块状硫化物的富集作用   总被引：5，自引：0，他引：5  

夏学惠 《化工矿产地质》2001,23(3):129-133

通过对黄铁矿叠层石组构、成分、微量元素、硫同位素、分子生物标志物与产出的构造环境背景的研究可知 ,黄铁矿叠层石的形成是通过沿同生断裂上升喷溢入海的热流体长期脉动作用 ,构成栖息在热水喷口与热液丘堤周围的嗜热微生物群落生存的食物链基础 ,使嗜热微生物围绕热水喷口繁殖的结果。沿同生断裂上升喷溢入海的热流体长期脉动过程中不断吸附、富集成矿元素 ,并将海水中的硫酸盐还原为H2 S。微生物吸附的Fe2 + 与S2 -作用 ,形成黄铁矿叠层石。微生物群落在热水喷口与丘堤附近不均衡发展 ,产生了成矿带内块状硫化物矿床中的黄铁矿叠层石丘堆。这种黄铁矿叠层石丘堆体是寻找富矿的显著标志 ,具有重要的成因与找矿意义  相似文献   

超细白云石矿粉润湿接触角的测定   总被引：9，自引：0，他引：9  

艾德生  李庆丰等 《岩矿测试》2001,20(2):97-99

根据Washburn方程，采用毛细管上升法，自行设计了简单的实验装置。提出了相对润湿接触角的概念，测定了3个超细CaCO3粉体在水中的润湿接触角。  相似文献   

Peat record of climate change for the last 3000 years in Yangmu, Mishan region of Sanjiang Plain     

XIA Yu-mei  WANG Pei-fang 《地理学报(英文版)》2001,11(4):454-460

The study of global climate change for the last 2000 years is very important for predicting climate evolution in the future. In order to explore the evidence of climate change for that period, the Chinese scientists made convincing statements using high-resolution substitution data such as tree-ring, coral and ice core. Continuous accumulated peat sediment is the better substitution data to provide climate information. Selecting the peatlands with a certain area and less human interference, th…  相似文献   

天水地区重力剖面测量结果与地壳结构   总被引：2，自引：0，他引：2       下载免费PDF全文

郭守年  徐敬文  孟万辉  王力  彭晓君  孟夏 《地震工程学报》1995,17(1):36-42

本文介绍了１９９０年期间在天水地区的重力剖面测量结果，以及用多层变密度直接反演法得到的该区地壳密度分层结构。结果表明，除近地表的沉积层外，该区地壳在纵向上可分为上、中、下三层，其各层的平均密度为２．６１、２．６６、２．８０ｇ／ｃｍ＾３，各层底面的平均深度分别为１６、２８、４５ｋｍ，且各层在横向和纵向上变化都比较剧烈。  相似文献   

作物霜冻与低温强度及冰核菌密度的关系   总被引：4，自引：0，他引：4       下载免费PDF全文

冯玉香  何维勋 《应用气象学报》1995,6(1):90-94

应用辐射型霜箱进行控制试验，研究玉米霜冻害程度与低温强度和冰核菌密度的关系。结果表明逻辑斯蒂克(logistic)方程只有在没有冰核菌或冰核菌密度很小的条件下才能描述霜冻与温度的关系，而理查兹(Richards)方程能够在各种冰核菌密度下很好地描述三者的关系。进而讨论了这种关系在确定霜冻指标，制作霜冻预报，选用防霜方法等方面的应用。  相似文献   

我国江淮流域近40年异常初终霜冻的分析   总被引：5，自引：1，他引：5       下载免费PDF全文

陈乾金  夏洪星 《应用气象学报》1995,6(1):50-55

该文用地面最低温度资料，以≤0℃作为霜冻指标，定量地确定出现异常霜冻的判别标准，研究了近40年初终霜冻异常的气候特征。结果表明:初终霜冻的异常明显存在地区差异。其变化周期以2～3年和准12年最普遍。其偏离均值大致有两种波型:反向变化和同向变化。前者在淮河流域较突出，后者在长江流域较普遍。当其出现反向变化趋势，且二者偏离均值达最大时，该时期为初霜冻异常偏早(偏晚)，终霜冻异常偏晚(偏早)的活跃期。同样，当初、终霜冻出现同向变化时，初、终霜冻异常活路期亦呈现同向变化。  相似文献   

Compton散射反问题的适定性的一些结果     

张廷杰  张兆田 《CT理论与应用研究》1995,4(3):40-42

本文对于Ｃｏｍｐｔｏｎ散射无损检测问题得出了非线性Ｖｏｌｔｅｒｒａ积分方程的模型，在某些通常容许的条件下证明了问题适定性，并探讨了一种图象重建的数值方法。  相似文献