接触角度对黄土-三趾马红土界面剪切力学特性影响研究

西北黄土高原第四系黄土广泛沉积于新近系三趾马红土之上形成粗糙接触的异质土界面,为典型的易滑层面.为探讨接触界面粗糙度对黄土-三趾马红土界面剪切力学特性影响,研制界面制样装置及剪切仪,开展简化黄土-三趾马红土界面直剪试验研究.结果表明:界面剪切破坏模式有齿间滑动、齿间滑动-齿面剪断、齿面剪断3种,界面接触角度越大,破坏模...     

单向流作用下伞式吸力锚基础的冲刷特征

伞式吸力锚(USAF)是一种新型的海上风电基础,与单桩基础相比,吸力锚基础(SAF)局部冲刷对风机稳定性的影响更为显著.因此,研究其冲刷特性对海上风电项目的建设具有重要意义.本文基于FLOW-3D软件,采用VOF法描述水体自由面,移动网格捕获冲刷形态随时间的变化,建立了三维USAF冲刷模型,并且与冲刷模型试验对比,验证...     

Hydrodynamic characteristics and sediment transport of a tidal river under influence of wading engineering groups

By taking the Yong River for example in this paper, based on the multiple measured data during 1957 to 2009, the change process of runoff, tide feature, tidal wave, tidal influx and sediment transport are analyzed. Then a mathematical model is used to reveal the influence mechanism on hydrodynamic characteristics and sediment transport of the wading engineering groups such as a tide gate, a breakwater, reservoirs, bridges and wharves, which were built in different periods. The results showed the hydrodynamic characteristics and sediment transport of the Yong River changed obviously due to the wading engineering groups. The tide gate induced deformation of the tidal wave, obvious reduction of the tidal influx and weakness of the tidal dynamic, decrease of the sediment yield of flood and ebb tide and channel deposition. The breakwater blocked estuarine entrances, resulting in the change of the tidal current and the reduction of the tidal influx in the estuarine area. The large-scale reservoirs gradually made the decrease of the Yong River runoff. The bridge and wharf groups took up cross-section areas, the cumulative affection of which caused the increase of tidal level in the tidal river.     

Application of FY-2C Cloud Drift Winds in a Mesoscale Numerical Model

Statistical tests and error analysis of cloud drift winds(CDWs) from the FY-2C satellite were made by using radiosonde observations.According to the error characteristics of the CDW,a bias correction using the thermal wind theory was applied in the data quality control.The CDW data were then assimilated into the GRAPES-meso model via the GRAPES-3DVar.A torrential rain event that occurred in northwestern China during 1-2 July 2005 was simulated.The results indicate that the CDW data were mainly distribute...     

宽窄相间河道水流紊动特性试验研究

为了探索宽窄相间河道的水流紊动特性，以西南地区宝兴河上游宽窄相间河段为研究对象，基于室内概化模型试验，采用多普勒声学流速仪（ADV）测量了室内模型典型断面上的三维瞬时流速，分析典型断面上的纵向时均流速、紊动强度、雷诺切应力和紊动能的分布规律。试验结果显示：宽窄相间水槽中，扩散段边壁的紊动强度大于中心区域的紊动强度，最大值位于0.2倍水深处；扩散段两侧坡脚处紊动能最大；侧壁区的平面和立面雷诺切应力最大值出现在扩散段内，中心区域最大雷诺切应力位于两槽间的中间断面处；扩散段内水流紊乱，两侧出现旋涡和涡脱，易造成侧壁侵蚀加强，引起河道拓宽。深入分析了宽窄相间河道水流的紊动特性，可为山区河流治理和自然灾害防治提供参考。     

三维大地电磁感应参量研究

本文讨论了大地电磁感应转换函数在使用上有争议的问题.用几个不同的三维(3D)模型计算了感应矢量和转换函数,特别对它们的虚部进行了分析.方形和矩形导电体的感应具有二维(2D)特征,其感应曲线可用来估计导体的埋深和范围.由二个埋深不同导体组成的结构,则表现出非二维特性,其感应函数曲线变化复杂,实虚矢量夹角大,两个转换函数的值即使在主轴方向也可能大小相当.      

地场综合工程地质定量评价方法

提要 本文论述了应用系统工程理论建立评价场地综合工程地质特性模型的基本思想、方法。利用这种方法使工程地质评价由定性到定量。由单一成为综合、使评价结合与实际更为符合。例证说明了该评价模型对实际场地评价的可行性。     

粤北地区夜雨特性分析

粤北位于南岭山脉南麓,地处亚热带,气候温和,雨量充沛。雨型以锋面雨为主,其次是对流雨、地形雨、台风雨。多年平均降水量约1200～2700mm,汛期(4～10月)的降水量约占年雨量的70～80％,而4～6月的降水量约占年雨量的49％。北部称架山南坡的坪溪站实测最大年雨量达4040mm,为粤北地     

航空摄影最佳曝光量的选择

分解力是评定影象质量的重要指标。本文介绍利用改进后的国产9 w测微密度仪,测定航空软片静态分解力与曝光量的关系。以最大分解力所相应的曝光量作为确定航摄软片感光度的基准,以此为基础,确定航摄底片的最大密度(D_(max))、最小密度(D_(min))、影象反差(△D)和平均密度(D_R)本文对国产1022T、1022P、柯达2402、2412等航摄软片进行了研究,其试验结果可作为今后修改航摄规范的基础。