摘要
为获得加筋土中筋材与填料间的作用力,国内外不少学者开展过拉拔试验,受测试仪器所限,多是研究双向土工格栅与砂土间拉拔力,建立拉拔力计算公式时,普遍认为它由表面摩擦力与横肋侧面阻力两者构成,而单向土工格栅因横肋的间距较大,目前对其与膨胀土填料间拉拔力的试验研究还鲜见。借鉴已有确定拉拔力的多种方法,提出最大拉拔力计算公式,采用自行研发的大型数控拉拔试验系统,利用其尺寸大、双向气囊加载、能消除侧壁摩擦等优势,优化试验方案设计以获取公式中两重要计算参数:一是将不同长度格栅剪去提供侧面阻力的横肋后实施拉拔,得格栅与填土间滑动摩擦系数;二是开展不同横肋数格栅的拉拔试验,测得单根横肋的端承侧面阻力。对比基于剪切破坏、冲切破坏及普朗特破坏3种机理分析所得端承侧面阻力结果,验证了试验测得的横肋端承侧面阻力较合理,并通过试验再次验证用最大拉拔力计算式分析不同型号、尺寸格栅加筋两种膨胀土及确定拉拔摩擦系数合理。研究成果可用于指导单向土工格栅加筋膨胀土工程的设计与施工以及格栅厂家对产品的改型升级。
In order to obtain the interaction force between reinforcement and filler in reinforced soil,many scholars have carried out pullout tests.Limited by testing instruments,they mostly study the pullout force between biaxial geogrid and sand.When establishing the calculation formula of pullout force,it is generally believed that it consists of surface friction force and resistance of transverse ribs.However,the pullout force between uniaxial geogrid and expansive soil fillers is rarely studied because of the large spacing between the transverse ribs.The calculation formula of maximum pullout force is put forward by using the existing methods for determining the pullout force.Using the self-developed large-scale numerical control pullout test system,and taking the advantage of its large size,two-way airbag loading and eliminating side wall friction,the test scheme design is optimized to obtain the important calculation parameters in the formula:one is to cut out the transverse ribs,which for providing side resistance,on the geogrids with different lengths and then carry out pullout test to obtain the sliding friction coefficient between geogrid and soil;the other is to carry out the pullout test of the geogrids with different numbers of transverse ribs to measure the bearing resistance of a single transverse rib.By comparing the results of bearing side resistance of transverse ribs based on shear failure,punching failure and Prandtl’s failure mechanism,it is verified that the bearing side resistance of transverse ribs measured by the test is more reasonable,and the rationality of analysing 2 kinds of expansive soils with different types and sizes of geogrid reinforcement and determining the pullout friction coefficient by the formula of calculating the maximum pullout force is verified again through test.The research result can be used to guide the design and construction of uniaxial geogrid reinforced expansive soil engineering and the upgrading of products by geogrid manufacturers.
作者
万亮
杨和平
倪啸
肖杰
WAN Liang;YANG He-ping;NI Xiao;XIAO Jie(Key Laboratory of Road Structure and Material of Ministry of Transport,Changsha University of Science and Technology,Changsha Hunan 410076,China;Anhui Agricultural Reclamation Group Co.,Ltd.,Hefei Anhui 230000,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2020年第1期32-41,共10页
Journal of Highway and Transportation Research and Development
基金
国家自然科学基金项目(50978035,51608053)
道路结构与材料交通行业重点实验室开放基金项目(kfj100208)
关键词
道路工程
膨胀土
拉拔试验
横肋端承侧面阻力
拉拔力
单向土工格栅
road engineering
expansive soil
pullout test
bearing side resistance of transverse rib
pullout force
uniaxial geogrid
