框架锚杆锚固寒区边坡的多场耦合分析  

Analysis on Coupling Model of Permafrost Slope Reinforced by Frame Structure with Anchors

作　　者：董建华[1,2] 代涛[1,2] 董旭光 孙国栋[1,2] DONG Jian-hua1,2 , DAI Tao1,2 , DONG Xu-guang1,2 , SUN Guo-dong1,2(1. Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province, Lanzhou University of Technology, Lanzhou 730050, Gansu, China; 2. Western Engineering Research Center of Disaster Mitigation in Civil Engineering of Ministry of Education, Lanzhou University of Technology, Lanzhou 730050, Gansu, Chin)

机构地区：[1]兰州理工大学甘肃省土木工程防灾减灾重点实验室,甘肃兰州730050 [2]兰州理工大学西部土木工程防灾减灾教育部工程研究中心,甘肃兰州730050

出　　处：《中国公路学报》2018年第2期133-143,共11页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(51778275;51268037);甘肃省杰出青年基金项目(145RJDA330);陇原青年创新人才扶持计划项目(LYRC2014002)

摘　　要：为了明确寒区框架锚杆边坡支护结构的工作机理,建立了框架锚杆支护冻土边坡的水热力耦合计算模型,采用有限元法进行了求解,基于MATLAB软件平台编写了计算程序,并通过已有的试验考证了程序的正确性。算例分析给出了边坡温度场、水分场、应力场和支护结构冻融反应的分布规律。结果表明:坡面上部受气温影响较大,融化时活动层含水量接近饱和,坡脚附近出现过饱和的"水泡";冻结时剪应力最大值是融化时的2倍,且分布均匀,边坡处于稳定状态,融化时剪应力在活动层和稳定冻土层交界面发生突变,边坡处于不稳定状态,该交界面是潜在滑移面;在一个冻融周期内,锚杆轴力、立柱内力和水平位移均先增大后减小,且随坡高逐渐增大,3种工况下结构内力和水平位移的关系为冻结时大于融化时大于初始时;冻胀时各层锚杆锚头处轴力增量最明显,增幅沿杆轴方向逐渐减小,融化时锚杆轴力和立柱内力大幅减小,且留有残余变形。因此,框架锚杆支护冻土边坡时,建议支护结构应按冻胀工况进行设计和计算。In order to clarify the working mechanism of frame supporting structure with anchors in the cold region, a coupled mathematical calculation model of heat-moisture-stress was established. The coupled model was analyzed by the finite element method, and a calculation program was written based on the MATLAB software. Besides, the program was verified by the existing experimental research. Through the examples, the distribution laws of the temperature field, moisture field and stress field of the slope and the freeze-thaw reaction of the supporting structure were obtained. The results show that the upper part of slope is greatly influenced by temperature, and the active layer is nearly saturated when it melts. And there exists the supersaturated ＂bubble＂ at the bottom of slope. In addition, the shear stress in the process of the freezing whose maximum value is twice as large as that in the process of thawing is evenly distributed. The slope is stable during this process. While there appears a shear stress mutation at the interface between active layer and stable frozen soil layer during the thawing. The slope is unstable, and the interface is the potential slip surface. In a freeze-thaw cycle, the axial force of anchor bolt, the internal force of column and the horizontal displacement increase first and then decrease, and all of them increase with the increase of the slope height. The laws of structural internal force and horizontal displacement under the three conditions from the largest to the smallest are freezing stage, thawing stage and the initial stage. The axial force at the anchor head in each soil layer dramatically increases during the frost heaving process, while the increase amplitude gradually decreases in the axial direction. In the process of thawing, the anchor force and the internal force of column decrease significantly, with a residual deformation produced. Therefore, when the permafrost slope is supported by frame anchor, the supporting structure is supposed to be designed and calculated unde

关 键 词：道路工程 冻土边坡 水热力耦合模型 框架锚杆 冻融作用 MATLAB 

分 类 号：U417.1[交通运输工程—道路与铁道工程]