In order to control the design size of the arch structure and clarify the local stress performance of the stepped arch of the long-span steel tube concrete arch bridge,taking the Daninghe Special Bridge in Wuxi as an example,the full-bridge model and the arch solid model of the arch bridge were established by the finite element software,and the most unfavorable load combination at the arch foot was obtained based on static analysis of the whole bridge,and it was loaded into the arch solid model for local stress analysis.The calculation results showed that the arch is mainly compressive stress,which meets the requirements of standard specifications.The maximum tensile stress is 4.167 MPa,which located at the lower edge of the arch rib,and it exceeds the design tensile strength of the concrete;The area with higher stress can be configured to strengthen the steel bar during designing,which would reduce the internal stress concentration of the structure.

路面基层对道路的服役年限和性能起到决定性的作用,是中国绿色道路建设的重点研究对象.文章基于再生循环理念,通过梳理固废再生材料作为路面基层材料的相关研究,重点探讨工业固废、建筑固废和生活垃圾等固废材料作为路面基层再利用的进展和存在的问题,并对固废再生路面基层材料应用发展趋势进行展望,研究可为固废再生新材料在路面基层中的应用提供参考.

In order to better analyze the interaction of abutment step foundation and ground in arch bridge design and provide reference for similar projects,a three-dimensional finite element model of arch foundation and ground slope was established to simulate and study the stress characteristics of the contact surface between foundation and ground based on the interface element,and the analysis was compared with the calculation results of traditional method and deformation coordination method.The results show that the stress distribution of the arch foundation contact surface along the transverse bridge and along the bridge is not uniform.In the transverse bridge direction,the stress on both sides of the edge is relatively large and the middle value is small.Along the bridge direction,the stress mutation occurs at the step corner.The result of finite element calculation considering the nonlinear interaction is between the two commonly used methods,and more reasonable,and can reflects the stress characteristics of structures more directly and comprehensively.

Taking a (130+1060+90)m railway suspension bridge as the research object, and taking the track-beam foundation model as the core, a simulation model of the coupling between the large span suspension bridge and the double track is constructed, including steel truss girder, main cable, suspender, orthotropic steel bridge deck, concrete bridge tower and track structure. The distribution law of the stress and deformation of the rail under the effect of temperature load, vertical load and braking load is revealed. The main conclusions are as follows: in order to optimize the stress and deformation of the rail, it can be considered to arrange the rail expansion regulator on the bridge. Setting the regulator at both ends of the steel truss girder of the bridge can significantly reduce the extreme value of rail stress and deformation; when the two lines are loaded simultaneously, the vertical deformation of the rail in the middle of the main girder reaches 2m. In this case, the bending force is the load that needs to be calculated more than the expansion force.

以天津市某滞洪区范围内高速公路路堤边坡为例,利用Midas GTS有限元软件模拟计算路堤边坡稳定性,对滞洪区路堤边坡水位变化情况进行逐一计算分析.采用正交设计试验方法分析比较洪水位降幅、水位降速和路堤填土渗透系数等因素对路堤稳定性影响的敏感性,为滞洪区内公路路堤工程提供了有益参考.

结合重庆峡谷地区某拱桥工程,详细阐述了极射赤平投影的基本原理和使用方法,提出了峡谷地区拱桥拱座岩质边坡稳定性分析思路和加固方案,为重庆等西部峡谷地区类似拱桥工程提供了有益参考.

节理在黄土地区普遍发育,一般成组成对出现,它的存在破坏了土体的整体性和连续性,形成的软弱面对黄土洞室和边坡的稳定性造成安全隐患.通过实地调查、数学统计等方法,对研究区节理分布特征和灾害类型进行系统研究,在此基础上将废弃黄土窑洞边坡变形破坏归纳为窑洞冒顶破坏和窑洞崩塌破坏2种模式.通过建立不同成对节理条件下的有限元模型,对废弃黄土窑洞边坡稳定性进行计算分析.结果表明:成对节理远离拱顶且间距越大时,稳定性越低,同时发育X节理时的稳定性比垂直节理时更低;成对节理对竖直位移的影响比对水平位移的影响大,而发育的X节理倾角越小时,窑洞更容易发生洞口局部崩塌及窑脸冒顶灾害;Mises等效应力在窑腿、立壁和拱顶不规则处更为集中,成对节理远离拱顶和间距增大时节理两侧的围岩应力差距越小,且当成对X节理倾角时变小时,最大等效应力值增大,节理附近更容易发生破坏.

以白鹿塬西南长安区四坡村废弃黄土窑洞边坡为研究对象,借助迈达斯(MADIS GTS NX)有限元软件模拟不同窑洞状态下窑洞边坡的应力应变特征,进而揭示废弃黄土窑洞边坡变形破坏机理并提出相应的防治措施.分析总结不同状态窑洞边坡的MADIS数值模拟结果显示,随着窑洞废弃,土体含水量的增加导致土体力学性质降低,局部临空面土体发生失稳掉落,加之降雨影响,土体力学性质进一步降低,窑洞拱形结构遭到破坏,从而引起窑洞所在边坡发生崩塌等整体失稳破坏.