碎石土地基湿陷性研究   总被引：1，自引：0，他引：1  

张管宏  谌文武  王生新 《岩土工程技术》2006,20(3):136-139

主要以甘南330 kV变电所碎石土地基的现场浸水载荷试验和室内实验为基础,根据湿陷变形的特征,分析了影响碎石土地基湿陷变形的主要影响因素,探讨了碎石土地基的湿陷机理。认为碎石等大骨架颗粒与细粒胶结物相填充的特殊结构是碎石土地基湿陷最主要的原因。碎石土由于浸水骨架颗粒之间抗剪、抗压强度降低而导致碎石土结构破坏,随之填充在骨架颗粒之间的细颗粒产生二次湿陷,两者引起土体体积减小所导致。  相似文献   

高塑性土路用性能试验研究     

施有志 《岩土工程技术》2006,20(6):271-274

结合一工程实例,通过浸水CBR试验,分析高塑性土在毛细饱水情况下的强度特征,揭示高塑性土的路用特性,并将室内研究成果结合现场工艺试验,研究在不添加外掺剂的前提下,直接利用高塑性土填筑路基的途径和方法。  相似文献   

大面积深厚杂填土地基处理技术     

刘焕存  高凤莲  许珩 《岩土工程技术》2006,20(6):307-310

通过一项具体的工程实例,论述了深厚杂填土地基的基本工程特性。介绍了一种处理深厚杂填土地基的新技术———重锤冲扩挤密灰渣土桩复合地基技术,并对施工过程的控制,以及施工效果的检测结果进行了分析,得出了对于大面积深厚杂填土地基采用此技术处理后,能够消除地基深部湿陷性,复合地基承载力可以满足200 kPa。  相似文献   

陕北奥陶纪米脂—绥德岩盐田米脂姬家峁矿区O_2m_5~6亚段岩盐资源及开采条件评价     

宋金保 《中国煤田地质》2006,(Z1)

在充分分析米脂—绥德岩盐田地质特征的基础上,对位于其中部的米脂姬家峁矿区O2m65亚段盐矿层赋存特征进行了研究,预测了矿区O2m65亚段岩盐资源储量,并对其开采条件进行了评价。  相似文献   

内蒙古东乌旗哈巴特盖银多金属矿土壤地球化学异常特征     

夏广清 《地质找矿论丛》2006,21(10):144-148

哈巴特盖测区1／5万土壤地球化学测量发现了4个异常区，多元素组合异常多分布在黑云母二长花岗岩的内、外接触带上，土壤地球化学异常特征显示本区成矿是多期次的，多元素组合异常在露头矿和盲矿上方均有出现，且异常连续、浓集中心明显，异常的强度和规模大，呈带状、宽带状或面状产出。  相似文献   

条形药包爆炸作用在土中显著影响范围的数值模拟     

董亮  赵成刚  蔡德钩  叶阳升 《工程地质学报》2006,14(2):263-270

爆炸固结法是软土地基处理的新方法。为了分析爆炸作用在土中的变化规律,通过有限元方法对单孔条形药包在土中爆炸的数值模拟,在验证计算结果与实测数据的基础上,对地基中单孔条形药包在上覆压力和药量两组爆炸参数下进行模拟对比分析,以解决在不同上覆压力和药量条件下条形药包爆炸作用在土中的显著影响范围。针对条形药包土中爆炸问题,运用ALE算法解决了炸药网格的畸变问题。研究结果表明,上覆压力发挥作用的主要时间不是在爆炸瞬间,而是在爆炸以后的时间段,主要的贡献是对爆炸产生的孔隙水压的消散作用。而炸药的药量对于布置爆炸孔和竖向排水通道的间距影响具有较大影响。  相似文献   

南京地区大气边界层晴空回波研究   总被引：10，自引：1，他引：10  

魏鸣  秦学  王啸华  蒋维楣 《南京气象学院学报》2007,30(6):736-744

以2005年6月23日南京多普勒雷达探测的晴空回波演变为例,分析了回波反射率与径向速度从夜间至上午的演变规律,利用实际的气象观测资料,对比了折射指数、地面温度、露点温度、水汽压和气压与回波强度的相关性,进一步探讨了边界层晴空回波与湍流混合特性之间的关系.研究表明:夜间大气的温、压、湿梯度使湍流出现,但湍流未充分混合使梯度维持,并导致折射指数的梯度增加,出现晴空回波;白天升温后湍流的增强使近地层大气充分混合,温、压、湿梯度减弱导致折射指数梯度减小,回波减弱消失.  相似文献   

Role of land-surface temperature feedback on model performance for the stable boundary layer     

A. A. M. Holtslag  G. J. Steeneveld  B. J. H. van de Wiel 《Boundary-Layer Meteorology》2007,125(2):361-376

At present a variety of boundary-layer schemes is in use in numerical models and often a large variation of model results is found. This is clear from model intercomparisons, such as organized within the GEWEX Atmospheric Boundary Layer Study (GABLS). In this paper we analyze how the specification of the land-surface temperature affects the results of a boundary-layer scheme, in particular for stable conditions. As such we use a well established column model of the boundary layer and we vary relevant parameters in the turbulence scheme for stable conditions. By doing so, we can reproduce the outcome for a variety of boundary-layer models. This is illustrated with the original set-up of the second GABLS intercomparison study using prescribed geostrophic winds and land-surface temperatures as inspired by (but not identical to) observations of CASES-99 for a period of more than two diurnal cycles. The model runs are repeated using a surface temperature that is calculated with a simple land-surface scheme. In the latter case, it is found that the range of model results in stable conditions is reduced for the sensible heat fluxes, and the profiles of potential temperature and wind speed. However, in the latter case the modelled surface temperatures are rather different than with the original set-up, which also impacts on near-surface air temperature and wind speed. As such it appears that the model results in stable conditions are strongly influenced by non-linear feedbacks in which the magnitude of the geostrophic wind speed and the related land-surface temperature play an important role.  相似文献   

Towards urbanisation of the non-hydrostatic numerical weather prediction model Lokalmodell (LM)     

Lina Neunhäuserer  Barbara Fay  Matthias Raschendorfer 《Boundary-Layer Meteorology》2007,124(1):81-97

Numerical weather prediction models are increasingly employed for providing meteorological data for urban air quality applications. Model resolution, physiographic parameters and surface-layer parameterisations need to be adapted to the requirements of the urban boundary layer. The Lokalmodell of the German Weather Service was triple-nested down to a horizontal grid resolution of 1.1 km, urbanised physiographic parameters were implemented, and an additional anthropogenic heat source was introduced. Results of a sensitivity study for a spring dust episode in Helsinki show a clear urbanisation effect of these measures on temperature, humidity and the partitioning of surface fluxes, leading to an increased Bowen ratio and heat storage and an urban heat island effect.  相似文献   

The role of surface heterogeneity in modelling the stable boundary layer     

A. McCabe  A. R. Brown 《Boundary-Layer Meteorology》2007,122(3):517-534

High-resolution numerical simulations are performed for three nights for each of two areas of the United Kingdom. Area-averaging techniques are then used to calculate effective stability functions for turbulence parametrizations in models using typical mesoscale and global spatial resolutions. Comparisons are made with parametrizations commonly used in numerical weather prediction models. The present results do not suggest that significant enhancement of the stability functions above 50 m is justified. Closer to the surface, more significant enhancement is observed in some regions. It is shown that the amount of enhancement is related to the variability of the orography.  相似文献