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Search Results: 1 - 10 of 126821 matches for " 曹周阳 "
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高填方大直径钢波纹管涵减荷试验
Load reduction experimental of high fill soil large diameter corrugated steel pipe culvert

,,,顾安全
- , 2018,
Abstract: 为了研究在钢波纹管涵顶铺设聚苯乙烯泡沫(EPS)板减小涵顶土压力及其调整土压力分布效果,依托四川广巴(广元―巴中)高速公路连接线项目路基工程,对其高填方大直径钢波纹管涵开展现场试验。在设计填方最高处的路堤下沿管涵纵向选取4个特征断面,其中1个为不减荷断面,另3个为涵顶平铺不同厚度EPS板的减荷断面,并对每个断面的特征点位进行应力应变测试,研究钢波纹管涵在减荷与否2种情况下的受力与变形随填土高度的变化规律和EPS板的减荷效果。研究结果表明:在未减荷断面,填土高度在约10 m之前的垂直土压力大于土柱压力、约10 m后小于土柱压力,最终的垂直土压力系数为0.9左右;在减荷断面,填土高度在约5 m之前垂直土压力大于土柱压力、约5 m之后小于土柱压力,最终的垂直土压力系数为0.46~0.47;钢波纹管涵两侧填土时,管涵变形表现为横向收敛、竖向拱起,随着填土高度的增加,其变形逐步调整,最终表现为横向挤胀、竖向收敛,且未减荷断面的竖向收敛略大于减荷断面,最终的收敛变形率均在??1.0%~??2.0%之间;在减荷与否2种情况下,钢波纹管涵顶垂直土压力随着填土高度的增加而增大,但增幅均逐渐减小;未减荷的钢波纹管随着填土高度的增加逐渐表现出柔性管的受力特性,而具有调节土压力的能力;在钢波纹管涵顶平铺柔性材料EPS板具有显著的减荷效果和调节土压力分布的作用;钢波纹管涵顶垂直土压力是影响其最终收敛变形的一个关键因素。
This study investigated whether the expanded polystyrene (EPS) plate laid on the top of corrugated steel culverts could reduce the earth pressure at the top of the culvert, and the law of adjustment of soil pressure distribution. Based on Sichuan Guang??Ba (Guangyuan to Bazhong) Highway subgrade project, a field test on large diameter steel corrugated pipe culvert under high fill was carried out. Four characteristic sections were selected on the longitudinal culverts at the highest embankment of design fill. One of them was an unloaded section,the other three were load reduction sections for laying different thickness flexible materials (EPS plates) on top of the culverts. Simultaneously, stress and strain tests were carried out on the characteristic points of each section. The variation of stress and deformation with the height of the fill and the reducing effect of the EPS plate were studied in the two cases, where the steel corrugated pipe culvert had reducing load and did not have reducing load. The results show that at the unloaded section, the vertical earth pressure is greater than the soil column pressure when the height of the fill is less than 10 m. Conversely, it is less than the soil column pressure when the height of the fill is greater than 10 m. The ultimate vertical soil pressure coefficient is about 0.9. At the load reduction section, the vertical earth pressure is greater than the soil column pressure when the height of the fill is less than 5 m. Conversely, it is less than the soil column pressure when the height of the fill is greater than 5 m. The ultimate vertical soil pressure coefficient is about 0.46 to ??0.47??. When the steel corrugated pipe culvert is filled on both sides of the culvert, the deformation of the pipe culvert is characterized by lateral convergence and vertical arch. The deformation gradually changes with the increase of the fill height. The deformation of the culvert finally manifested as lateral bulging
地图水系综合中等高线簇与河网协同的汇水区域提取方法
舒方国,龙毅,,
测绘学报 , 2013,
Abstract: 在地图水系自动综合中河流选取需要建立对不同河流重要性程度的有效判别。由于河流汇水区域直接反映河流的作用空间,因而其面积大小成为关键性的量化指标。目前基于河流的汇水区域自动提取方法主要从河流单一要素出发,按“空间均衡竞争”思想平分河流之间的区域,由于未考虑地形因素使得提取的汇水区域往往存在偏差,而传统基于DEM的汇水区域提取虽然考虑了地形,但没有与河流目标建立显性的对应关系。河流是一种天然的沟谷地性线,与山脊线具有对生互补的空间耦合关系,本文提出了一种等高线簇与河网双要素协同的河流汇水区域提取方法,该方法对河流与等高线的目标集合构建约束Delaunay三角网(CD-TIN)并将三角形分类,对不同类型的三角形分别采用骨架线提取规则与梯度向量引导的分水线搜索规则提取分水线段,连接形成网络结构并依此计算各河段的汇水区域。实验结果表明,本算法能更准确地提取河流汇水区域,从而为河流综合选取提供有效支持。
纳米坡缕石/铜复合材料对钢球摩擦副的摩擦学性能
吴雪梅,元康,杨绿,
复合材料学报 , 2014,
Abstract: 采用化学还原法和球磨共混添加法制备了纳米坡缕石/铜(P/Cu)复合材料,采用粒度分析仪和透射电子显微镜(TEM)对复合纳米粒子的粒度和形貌进行表征。利用四球摩擦磨损试验机考察了不同纳米P/Cu添加量和不同P与Cu配比的复合粉体作为润滑油添加剂对高副钢球摩擦副的摩擦学性能,利用扫描电子显微镜(SEM)、X射线能谱仪(EDS)对摩擦表面进行形貌、元素性能分析。结果表明,所制备的纳米P/Cu粒径基本小于100nm,分散稳定性良好,在纳米P/Cu为1wt%且P:Cu=3:1(质量比)添加量下表现出最优的摩擦学性能,其钢球磨斑直径比基础油的减小了20.7%。纳米P/Cu可在摩擦表面生成含Mg、Al、Si和Cu等元素的自修复膜,补偿摩擦磨损且使摩擦表面变光滑。
巢湖陆向湖滨带常见野生植物对磷缓冲能力的影响
,,,,秀云,周易,宋春雷
长江流域资源与环境 , 2012,
Abstract: 湖泊陆向湖滨带缓冲磷扩散的机制尚未得到充分地研究。系统分析了2011年4~7月巢湖陆向湖滨带5种野生植物的生长状况与根际土不同形态磷的含量和吸附行为。结果表明土壤磷的吸附行为可用Langmuir方程加以描述。与对照相比,艾草和小飞蓬根际土总磷含量明显较低,磷的最大吸附量(Qmax)明显较高,而小蓟和狗尾巴草根际土速效磷含量明显较高,Qmax与磷吸附强度明显较低。植物根与茎长均随季节增加,相应的土壤磷饱和度下降。因此,植物吸收与土壤吸附是陆向湖滨带缓冲磷扩散的重要机制。有机质可通过增加速效磷含量和Qmax值调节土壤磷平衡浓度(EPC0)。小飞蓬和艾草根际土的EPC0值明显较低,磷吸附能力较强。而小蓟和早熟禾根际土的EPC0值明显较高,故易成为向湖泊扩散的磷源
具有黏滞阻力时的最速降线
嘉炜,,过增元
力学与实践 , 2011, DOI: 10.6052/1000-0992-lxysj2011-123
Abstract: 针对实际应用中存在黏滞阻力的最速降线的问题,首先推导出适于此类问题的解除约束的广义变分原理,它适用于具有摩擦阻尼和多自由度系统优化的问题.得到描述有黏滞阻力情况下最速降线相关函数的微分方程,它在黏滞阻力为零时即退化为滚轮线.利用MATLAB数值计算给出了最速降线受黏滞阻力的影响在黏滞阻力系数较小时最速降线趋于变凹,当阻力系数增大到一定值之后最速降线趋于平缓,当阻力系数很大时最速降线趋于直线.
高填方双管涵洞减荷试验研究
,王晓谋,王俊伟
工业建筑 , 2011, DOI: 10.13204/j.gyjz201104019
Abstract: 为解决高填方涵洞受力过大的问题,在一双管涵洞上铺设不同密度、不同厚度的单层或双层可发性聚苯乙烯板(EPS板)进行减荷试验,并与未减荷段进行对比,结果表明涵顶铺设EPS板可以大大减小涵洞受力,涵顶竖向土压力仅为未减荷段的1/3、土柱压力的1/2;同时,EPS板铺设越厚,减荷效果越好,但其效果随板厚的增大而递减,双层叠加组合EPS板减荷效果优于单层减荷;涵顶铺设EPS板改善涵洞纵向不均匀沉降效果明显。这一减荷措施不仅可以减小涵洞受力,同时也可以防止涵洞开裂、减少涵洞纵向凹曲不均匀沉降等病害,具有有重要的价值和意义。
变质软岩路堤填料湿化变形规律研究
杜秦文,刘永军,
岩土力学 , 2015,
Abstract: 采用双线法,对十堰—天水高速公路安康西段的变质软岩路堤填料,在两种密度条件下进行了大型三轴试验,同一竖向偏应力下饱和与风干状态填料应变的差值即为湿化引起的应变,对其变化规律进行分析,结果表明:填料的湿化变形发展呈两个阶段,临界湿化应变的大小与竖向偏应力和围压的比值密切相关,同一密度、不同围压条件下的各曲线变化点的湿化应变值较为一致;填料密度增大,则变化点的湿化应变值增加,说明密度和围压不仅影响湿化变形的大小,还影响其发展规律。根据3种围压条件下的试验结果,对两种密度的填料,分别建立了填料湿化变形发展规律的公式,并用新的第4种围压条件下的试验结果进行校核,吻合程度较好。该公式可用于分析高速公路施工中路堤湿化变形的大小及发展规律。
基于MBD模型的工序模型构建方法
于勇,,,赵罡
- , 2018, DOI: 10.3785/j.issn.1008-973X.2018.06.001
Abstract: 针对“基于模型驱动”的产品研制模式中,难以高效地构建工序模型以准确描述实际加工过程的问题,开展机加件工序模型构建方法的研究,提出以基于模型定义(MBD)模型为输入的工序模型构建方法.以零件MBD模型为输入,采用CAD系统二次开发技术进行模型参数提取,提出MBD模型参数信息结构化表达方法.交互进行加工工序设计,建立常见的机加工序工艺信息库辅助具体加工方案设计;根据MBD模型参数和工序参数得到工序模型构建数据文件.读取工序模型构建数据文件,实现工序模型快速建模.开发了工序模型辅助构建工具,以某航空企业典型机加件为例,验证了所提方法的有效性.
Abstract: The construction method for in-process model of machining process was analyzed to meet the requirement of efficient construction of in-process model containing accurate machining process information in "model-driven" product development mode. A new method to construct in-process model based on model-based definition (MBD) model was proposed. Taking MBD model as input, feature parameter extraction was completed and stored in proposed structure by CAD system secondary development technology. Then machining procedure was interactively designed and specific machining scheme were worked out by the machining process knowledge base. The in-process model construction data files were obtained according to the MBD model parameters and machining procedure parameters. The in-process model was rapidly constructed based on the data files. A tool was developed to assist in-process model construction, and some typical machining parts of an aviation enterprise were taken to verify the proposed method.
高填方钢波纹管涵垂直土压力计算
Calulation of vertical earth pressure of high-fill steel corrugated pipe culvert

,,,顾安全,谢永利
- , 2018,
Abstract: 引入表征钢波纹管波形特性的惯性矩计算方法,通过Spangler管-土相互作用模型,得到了钢波纹管涵竖向收敛变形计算公式; 假设管涵顶部填土为半无限直线变形体,将条形基础沉降倒置后比拟上埋式管涵的受力模型; 基于弹性力学推导的基础沉降计算公式,着重考虑管涵侧向土体压缩变形与管涵自身的竖向收敛变形之差,推导了管涵垂直土压力的计算公式; 以广巴广陕高速公路连接线吴家浩-张家湾段高填方钢波纹管涵工程为例,对涵顶垂直土压力进行了现场测试,将采用公式计算所得涵顶垂直土压力与现场试验结果和应用实测沉降差反算的垂直土压力进行了对比。研究结果表明:涵顶垂直土压力随填方高度的增加而增大,填土至设计标高后涵顶垂直土压力计算值、实测值和反算值分别为224.14、221.98、211.33 kPa,计算值与实测值的相对误差约为0.9%,反算值分别比计算值和实测值小6.1%、5.0%,且计算结果、反算结果均与实测涵顶垂直土压力变化规律一致,填方越高,误差越小。可见,提出的高填方钢波纹管涵垂直土压力计算公式可行,不仅考虑了涵侧土体的抗力系数和基床系数,而且体现了钢波纹管的变形与受力特征。
A method involving the inertia moment calculation for characterizing the wave characteristics of steel corrugated pipe was introduced. Through the Spangler pipe-soil interaction model, a computationalformula of the vertical convergent deformation of steel corrugated pipe culvert was obtained. The top fill of the pipe culvert was deemed to be a semi-infinite straight line deformation body, and the settlement of the strip foundation was inverted to assimilate the stress model of buried pipe culvert. Based on the foundation settlement calculation formula derived from the elastic mechanics, the settlement difference between the compression deformation of the soil and the vertical convergent deformation of the pipe culvert was mainly considered and the calculating formula of the vertical earth pressure of the tube culvert was derived. Taking the project of the high-fillsteel corrugated pipe culvert at the Wujiahao to Zhangjiawan Section of the Guangba-Guangshan Highway as an example, the field test of vertical earth pressure on the top of steel corrugated pipe was performed. The vertical earth pressure computed by the formula was compared with the field test value and back-calculated result using the measured settlement difference value. Research result shows that the vertical earth pressure at the top of the culvert increases with the increase of filling height. The calculated values, measured values and inverse values of the vertical earth pressure at the top of the culvert after filling to design elevation are 224.14, 221.98 and 211.33 kPa, respectively, the relative error between the calculated value and the measured value is approximately 0.9%, and the inverse values are 6.1% and 5.0% less than the calculated and test values, respectively. The results of calculation and inverse calculation are consistent with the variation rule of the measured vertical earth pressure, and the higher the fill, the more consistent are the results. The proposed calculation formula of the vertical earth pressure of high-fill steel corrugated pipe culvert is feasible because it considers
(-)-Frontalin的形式合成有机化学
, 孙默然, 其伟, 朱明, 白磊,, 杨华
有机化学 , 2013, DOI: 10.6023/cjoc201308005
Abstract: (-)-Frontalin是用于手性叔醇构筑测试的基准分子之一.以本实验室发展的[2,3]-Meisenheimer重排为关键反应,以L-天冬氨酸衍生物为起始原料,经Wittig反应、酯基还原、二醇双乙酰化、[2,3]-Meisenheimer重排等7步反应,实现了(-)-Frontalin关键中间体的合成,总收率为34%,ee值为94%.论文工作将[2,3]-Meisenheimer重排构筑手性叔醇的底物范围,从α,β-不饱和酯基的共轭烯烃扩展至孤立烯烃,充分证明了用[2,3]-Meisenheimer重排构筑手性叔醇更加一般的特征.
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