Consolidation behavior of soft deposits considering the variation of prefabricated vertical drain discharge capacity

This paper is primarily focused on why and how to consider the varied discharge capacity during simulations of consolidation via prefabricated vertical drains (PVDs) for soft soil deposits. First, the existing studies regarding discharge capacity are summarized and discussed. These studies conclude that the discharge capacity of PVDs at sites vary with the confining pressure and consolidation time. Next, a series of analytical solutions that consider the variation of discharge capacity with ground depth, consolidation time or both simultaneously are presented and compared. Applications of these solutions and of the newly introduced parameters are described. Then, a well-documented case history on ground treatment with PVDs is analyzed, in which the parameters related to the time-dependent discharge capacity were obtained from laboratory tests. A comparison between a classical solution and the newly presented method indicates that consideration of the varied discharge capacity in the consolidation theory can better predict the consolidation process of PVD-improved ground.     

2000—2005 年莱州湾盐度的变化及其主要影响因素

基于2000 年8 月, 2002 年8 月, 2004 年9 月, 2005 年5 月, 2005 年7 月及2005 年9 月莱州湾的大面观测资料以及黄河利津站2000—2005 年入海径流量资料, 分析了黄河入海径流对莱州湾盐度分布的影响, 通过计算莱州湾的平均盐度发现2003 年之后莱州湾平均盐度较2003 年之前明显降低。在考虑黄河入海径流量、降水、蒸发及与北黄海的水交换等因素的基础上建立了箱式模型, 并以此模型模拟了近年来莱州湾平均盐度的变化, 同样看到莱州湾平均盐度的显著降低已在2003 年发生, 其主要原因是黄河入海径流量的增加。分析模型结果得出近年来黄海入海径流量的变化不仅决定着莱州湾平均盐度的年际变化, 而且还主导着莱州湾月平均盐度的变化。     

银川平原地下水补径排特征及其变化规律

通过对银川平原地下水资源的调查,分析调查区地下水补给、径流和排泄特征及其环境地质成因,为建立银川平原地表水地下水配置模拟模型及国土资源综合规划提供地质依据.     

Physiogeographic features of the Oubangui catchment and environmental trends reflected in discharge and floods at Bangui 1911–1999, Central African Republic

Varying discharges of large rivers observed over long periods can reflect environmental trends like ‘climate change’ within the catchment (e.g. ongoing aridification results in a reduced discharge). The present study on the Oubangui River in Central Africa first lines out some physiogeographic features of the almost 500 000 km² large catchment situated on the vast north equator rise. Subsequently, a discharge record from 1911–1999 of Qmax. and Qmin., covering data for 73 years from the gauge station Bangui, is examined. Annual variability of Oubangui floods is generally high and shows over the past years, especially since the mid to end 1960s, a less significant trend to a slight depletion of maximum discharge. Frequency analysis (Gauss, Gumbel, Weibull) of floods resulted in return periods between 7 and 35 years. Distributions calculated after Gumbel generally gave the best results. No linear and simple evidence exist of the tendency of the river to reduce discharge because of a depletion of rain fall as the Oubangui's floods are again increasing since the mid 1990s. Finally, the consequences of Oubangui flood hazards for the growing town of Bangui are discussed. Flooding of urban areas from exceptional high Qmax. discharge is spatially reconstructed for the floods in 1916, 1962, and 1999.     

闪电的光辐射能分布特征

对TRMM卫星上装载的闪电成像仪(LIS)所获取的闪电光辐射能进行了分析,发现在不同地区和不同的空间、时间尺度上闪电光辐射能都很好地遵循对数正态分布。文中利用了一个国际上公认的一维雷暴云起电和放电模式,对闪电放电中和的电荷量进行了数值模拟。蒙特卡罗算法表明,闪电放电所中和的电荷量也遵循对数正态分布,云中的软雹浓度、破碎系数、温度递减率、放电的电场阈值等参量的综合作用可以对其进行较好的解释,而其中任意一种参量的单独作用则不然。     

利用天气雷达观测资料预报小流域流量

将天气雷达降水临近预报与半分布式水文模型TOPMODEL(TOPography based hydrological MODEL)相结合,研究了降水临近预报延伸小流域流量预报预见期的可行性。研究流域为淠河(安徽省内)上游的佛子岭流域(1813km~2)内划分出的6个上游源头小流域(约60—100km~2)。用雷达估测的降水得到的流量输出作为参考,与1h降水临近预报得到的流量输出进行比较。结果表明:定量降水临近预报准确率是延伸小流域流量预报预见期的关键;基于所研究的个例,定量降水临近可以延长小流域流量预报预见期平均约0.7h左右,但其延长程度还受到具体降水过程、流域属性等的影响。