A semi‐analytical solution of surface flow and subsurface flow on a slope land under a uniform rainfall excess

A new approach is proposed to analyze the surface flow and subsurface flow passing over a pervious ground under a uniform rainfall excess. The flow field is divided into two regions that are called water layer and soil layer. To figure out the hydraulic behavior of overland flow on an inclined plane under a rainfall event, the simplified Navier–Stokes equations are employed for the surface water flow, and the flow inside the soil layer is porous media flow, which is governed by Biot's (1956, 1962) theory of poroelasticity. The velocity distribution of overland flow is nonzero at the ground surface. The relation between water depth and slope length was developed first. The profile of surface water flow was then found backwards from the downstream end of the flow section by the Runge–Kutta method. After that, the flow velocity and flow discharge of each layer could also be obtained via the water depth. Finally, the variation of fluid shear stress inside the soil layer is also discussed. Copyright © 2011 John Wiley & Sons, Ltd.     

菏泽市气候极值的统计分布和再现期研究

科学合理地估算某地区的气候极值再现期是气象科技服务的重要内容,对当地经济建设具有重要意义。对菏泽市35种气候极值,分别都用皮尔逊Ⅲ型（Pearson Ⅲ）、对数正态（log normal）、耿贝尔（Gumbel）、韦伯（Weibull）分布函数进行拟合,用χ2检验选出最优者。使用选出的最优分布函数,用多个再现期算出再现期极值,列成表格以备气象服务中使用。通过最优分布函数的选取,对哪个类型的气候要素较多服从于哪个分布函数问题进行了研究。研究结果发现极端气温类型的极值和日数类型的极值较多服从于皮尔逊Ⅲ型分布,降水和其他类型的极值较多服从于耿贝尔分布。简要介绍了计算中使用Excel的技巧。     

地震序列下落梁震害的防灾设计分析

地震的发生具有丛集的特征,主震发生之后通常伴随余震,主震震级越高其余震震级亦越高,对结构的破坏越大.桥梁结构作为重要交通枢纽工程,其在整个地震序列发生时应能确保通行.为得到桥梁结构在地震系列作用下的响应,选用集集地震序列对桥梁进行地震响应分析,结果显示结构在主震作用下发生落座,余震时有发生落梁的可能,对结构设置连梁装置,验证其在地震序列中的防落梁效果.结果显示连梁装置可有效减小桥梁上、下部结构相对位移,同时可提高结构整体性,使各桥墩平均分配地震力,并能在地震序列中有效防止落梁震害的发生.     

Rapid repair of severely earthquake-damaged bridge piers with flexural-shear failure mode

An experimental study was conducted to investigate the feasibility of a proposed rapid repair technique for severely earthquake-damaged bridge piers with flexural-shear failure mode. Six circular pier specimens were first tested to severe damage in flexural-shear mode and repaired using early-strength concrete with high-fluidity and carbon fiber reinforced polymers (CFRP). After about four days, the repaired specimens were tested to failure again. The seismic behavior of the repaired specimens was evaluated and compared to the original specimens. Test results indicate that the proposed repair technique is highly effective. Both shear strength and lateral displacement of the repaired piers increased when compared to the original specimens, and the failure mechanism of the piers shifted from flexural-shear failure to ductile flexural failure. Finally, a simple design model based on the Seible formulation for post-earthquake repair design was compared to the experimental results. It is concluded that the design equation for bridge pier strengthening before an earthquake could be applicable to seismic repairs after an earthquake if the shear strength contribution of the spiral bars in the repaired piers is disregarded and 1.5 times more FRP sheets is provided.     

基于欧拉—拉格朗日模式的风沙跃移数值模拟方法

通过对沙粒的起动过程以及粒床相互作用机理进行参数化处理,利用计算流体力学方法与离散动力学模拟对风场和沙粒进行耦合迭代,建立了基于欧拉—拉格朗日模式的、适用于研究风沙流二维特征的风沙跃移数值模型。通过模拟沙粒集团以及单颗沙粒跃移运动的随机特征,有效描述了风沙流垂向以及沿程变化规律,并且能够输出任意时刻每颗沙粒的空间位置、速度和加速度等信息。输沙通量的空间分布与现场观测实验数据有较高的吻合度,摩阻风速和风速廓线两个宏观物理量的变化情况与风沙流形成和发展的物理实际相符,说明了本数值模型和计算方法的合理性。     

超高层建筑桩筏基础的桩顶反力计算研究

根据上海高88层、筏板厚度为4 m的金茂大厦和高101层、筏板厚度为4.5 m的上海环球金融中心桩筏基础的实测沉降资料,论证超高层建筑的桩筏基础为弹性体。对以上两幢超高层建筑和正在建造中的高121层、筏板厚度为6 m的上海中心大厦的桩筏基础,采用偏心受压公式和高层建筑与地基基础共同作用理论方法(混合法)进行详细对比计算,论证按弹性体计算桩顶反力的合理性,阐明《建筑桩基技术规范》(JGJ 94–2008)的3.1.8条的正确性和合理性。期望能够改变过去按偏心受压公式计算桩顶反力的传统观念,提高设计水平。     

Geological Setting and Origin of Mo–W–Cu Deposits in the Honggor–Shamai District,Inner Mongolia,North China

Twenty‐one Mo–W–Cu deposits and prospects have been discovered in the Honggor–Shamai district, Inner Mongolia, north China during past 5 years. This district is located in the central and western parts of the Chagan Obo–Aoyoute–Chaobulen tectono‐magmatic belt, which is part of the Central Asian Orogenic Belt. The Mo–W–Cu deposits in the district are associated with Mesozoic granitoid intrusions and occur as veins, stockwork, and dissemination. The geological features of these newly discovered deposits are similar to porphyry‐type deposits worldwide. Two mineralization events have been identified: Indosinian (235–224 Ma) and Yanshanian (137–131 Ma). It is proposed that these deposits and prospects in the Honggor–Shamai district were related to the post‐collisional extension linked to the Indosinian orogeny during the Middle–Late Triassic period, but some of those deposits were overprinted by mineralization associated with the Cretaceous magmatic‐hydrothermal (Yanshanian) event.     

微量元素Fe、Mn、Co对有毒甲藻生长和产毒的影响

实验通过培养基筛选实验和在此基础上的微量元素Fe、Mn、Co正交实验对海南三亚热带珊瑚礁海域有毒甲藻Coolia monotis的生长和产毒影响进行了初步研究,以期获得充足的原材料进一步开展毒素化合物的研究.实验结果表明,在Erd、f/2、GP和K 4种培养配方中,K系列培养液更适合于C monotis的培养.在以2K为基础培养配方的微量元素正交实验中,Fe、Mn和Co 3种微量元素的浓度配比为:Fe:2×10<'-5>mol·L<'-1>,Co:1×10<'-6>mol·L<'-1>,Mn:5×10<'-7>mol·L<'-1>时能获得最大的平均生长速率;而Fe:5×10<'-6>mol·L<'-1>,Co:1×10<'-7>mol·L<'-1>,Mn:2×10<'-6>mol·L<'-1>的条件下C monotis的毒性最强.     

Study on new optimum parameters in MT repeated survey

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