含流砂地基防洪堤桩基施工

分析了广西藤县城区河西防洪堤的工程地质情况,提出了采用人工和机械挖孔桩方案对大堤含流沙地基进行基础加固。论述了桩基施工的工艺流程和技术措施,总结了在含有流沙的地基进行防洪堤桩基施工各环节中,确保工程质量和施工安全的技术方法。     

砂脉(砂注入体)型储层与油藏——以松辽盆地长垣地区西部萨葡夹层为例

松辽盆地西部萨葡夹层是一套夹持于萨尔图和葡萄花油层,且以泥岩为主的地层,最近在该地区成功获得了多口高产井。通过对岩芯、测井及其地震资料的精细解析发现,萨葡夹层的泥岩中发育了大量的砂脉(砂注入体)和断层,油藏与这套砂注入体和断层密切相关,形成了一种新的砂脉型储层或油藏。其具有如下特点:①没有稳定的层位,侧向连续性极差,很难对比; ②没有确定的形态,不定形团块状居多; ③砂脉的顶、底面或侧缘与围岩呈侵入接触关系; ④砂脉中多含有漂浮状的撕裂泥砾; ⑤在地震剖面上两侧或一侧必有断层; ⑥剖面上地震反射轴紊乱,中断、膨大、弯折等现象常见,平面上为次圆形或星点状不均一的高阻抗团块; ⑦液化流动具有很好的分异作用,可以使砂注入体成为良好的储层; ⑧砂脉型油藏一般具有自己独立的油水和压力系统,在区域上没有统一的油水界面。     

黄河宁夏四排口河段河床冲淤变形的计算

黄河宁夏平罗四排口“Ω”型河道“裁弯取直”工程的实施, 引发了该段河道河床边界条件的剧烈改变。为了掌握工程运行后该段人工开挖引河中水流运动、泥沙运移以及河床迁移演变的发育、演化规律, 项目组多次赴平罗黄 河四排口进行现场考察与实地取样、测量。根据所研究河段初始地形、流场分布情况以及初步预测的河床变形规律布设了一系列淤积测验断面, 随后多次对其展开现场实测, 得到了该段河道的河床演变规律、悬移质泥沙粒径和含沙量的分布情况与岸边丁坝影响下河道主流的演进变化规律。依据实测结果计算、分析了工程运行初期河床的平均冲淤变化程度( 1.6077 m) 和河段整体冲刷量( 356.4908万 m3) , 根据分析结果提出了进一步加固丁坝群后左岸岸坡的建议。     

钱塘江海塘的古今

钱塘江海塘为钱塘江河口防洪、防潮江堤的习称,从土塘到石塘到现代标准海塘,历经两次大的飞跃.简述其飞跃过程与明清鱼鳞石塘的主要技术特征,重点阐明标准海塘的设计标准、技术特色及其实施过程.     

植物生态护岸技术的效果分析——以漳河下游陈村险工为例

根据植物护岸机理,以漳河下游河道陈村险工为具体研究对象,通过数学模型模拟,分析了植物根部的加筋作用和植物地面以上部分对水流拖曳力的分担作用,及其对减缓丁坝冲刷的贡献。研究发现:种植植物后水流对丁坝附近土壤的有效拖曳力虽然随流量的增大而增大,但增幅减缓,说明植物的阻滞作用也随流量的增大而增大;在研究的流量范围内,种植植物后丁坝的冲刷深度比种植植物前减少了40～126cm。     

Investigation into nitrided spur gears

The cold forging method has been widely used in industry to produce machine parts. In general, gears are produced by shaping or hobbing. One of the shaping techniques is precision forging, which has several advantages over hobbing. In the present study, cold forging of spur gears from Ti-6A1-4V material is introduced. To improve the surface properties of the resulting gears, plasma nitriding was carried out. Nuclear reaction analysis was carried out to obtain the nitrogen concentration, while the micro-PIXE technique was used to determine the elemental distribution in the matrix after forging and nitriding processes. Scanning electron microscopy and x-ray powder diffraction were used to investigate the metallurgical changes and formation of nitride components in the surface region. Microhardness and friction tests were carried out to measure the hardness depth profile and friction coefficient at the surface. Finally, scoring failure tests were conducted to determine the rotational speed at which the gears failed. Three distinct regions were obtained in the nitride region, and at the initial stages of the scoring tests, failure in surface roughness was observed in the vicinity of the tip of the gear tooth. This occurred at a particular rotational speed and work input.     

渐开线直齿圆柱齿轮铲齿成形铣刀轴剖面齿形的计算机辅助设计

本文论述了渐开线直齿圆柱齿轮铲齿成形铣刀轴剖面肯形几何模型的建立方法，导出了齿形曲线的参数方程，进行通用Ａｕｔｏｌｉｓｐ程序设计，并举例说明调用程序绘图的方法。     

Thermo-elastohydrodynamic lubrication of an involute gear

This paper analyses the thermo-elastohydrodynamic lubrication on an involute spur gear tooth surface and the influence of the inlet temperature of the lubricant. The oil film temperature distribution shows a minimum near the point where the pressure distribution is a maximum and the energy loss a minimum. Then the temperature increases slightly in the outlet region. Calculated results show a decrease of a few percent in the maximum pressure distribution compared with an oil film on a rigid surface. Based on oil film thickness and gear tooth deflection, the load sharing coefficient and the relative transmitting errors are calculated. The behaviour of the oil film due to the variation of the normal tooth load at the transition point of the meshing is investigated also     

复杂潮汐深水海域大型袋装砂施工关键技术研究

由于某陆域形成项目施工水域水深变化和水下地形起伏较大,海流的流向、流速差异明显,专业铺排船铺设袋装砂受流速急、水深大等条件限制,在该区域会出现施工困难的现象。通过现场试验,围堤大型深水袋装砂全部改用对拉船施工,在施工水域取得了满意的效果,拓宽了对拉工艺的适用范围。用对拉船代替专业铺排船,并对现有对拉船施工工艺进行改进,施工过程中采用浮管分流和锚拉工艺,并辅以袋体四角系上浮标定位测量,袋体之间错缝搭接,提高了大型袋装砂的施工效率和质量,充灌一个大型袋装砂的时间可缩短25%,袋体充灌更加饱满平整,定位精度高,保证了充填堤的层间抗滑稳定性,减少了由于袋体铺设位置偏移而增加的抛填量。该项技术解决了复杂潮汐海域深水大型袋装砂的铺设施工难题,工程造价低,堤身整体强度高,结构可靠,对近海深水岸线的开发造陆具有重要的借鉴意义。     

抚河尾闾抚东堤防洪保护区洪水风险分析

江西省是洪涝灾害发生较频繁的区域,特别是受上游洪水和鄱阳湖水顶托双重作用的赣抚尾闾河段。分析其洪水风险,对于提高江西省防洪减灾能力、减轻或避免生命财产损失是非常必要和迫切的。以抚东堤防洪保护区为例,利用MIKE软件建立一维、二维耦合模型,分析不同溃口在标准内(20 a一遇)和标准外(50 a一遇)洪水叠加鄱阳湖1954年型设计洪水条件下的洪水演进过程、淹没范围和淹没损失等。研究结果表明,由于抚东堤防洪保护区内地形起伏较大,不同河段的溃口溃决后的风险大小不同,其中上段李家渡水文站下侧溃口发生溃决时,洪水影响最大。研究结果对于类似区域洪水风险分析具有一定的参考价值。