桩承式路堤土拱演化的二维钢棒相似土模型试验

发布时间：2018-05-27 08:36

本文选题：道路工程 + 桩承式路堤　；参考：《中国公路学报》2017年10期

【摘要】：为了解桩承式路堤的变形类型与土拱效应随桩间土下沉的演化规律,并为参数取值提供参考,开发了可考虑桩承式路堤多个单元相互影响的多沉陷门(Multi-trapdoor)试验装置,考虑填料高度H、桩间净距s-a与桩径参数a,进行了1组随桩间土下沉的土拱演化模型试验。试验采用椭圆钢棒相似土作为填料,将采用砂填料的平面应变试验简化为二维试验条件,消除了前后挡板摩擦力的影响。通过粒子图像测速技术获取了填料随桩间土下沉过程的全场变形,利用自制荷载板精确地测试了填料底面的桩土荷载分布,得到不同参数组合下的桩承式路堤土拱变形类型和桩土应力比变化规律;同时利用试验结果总结了3种演化模式的适用条件。结果表明:钢棒相似土能够很好地模拟实际砂填料的平面应力-应变特性,桩承式路堤土拱效应存在三角形扩展型和等沉面型2种主要的演化模式,与三角形扩展模式相比,等沉面模式路堤表面无差异沉降,土拱效应发挥程度高,且桩土应力比随桩间土下沉降低比例较小,另一种塔形升高模式可以看作三角形扩展型向等沉面型转变的一种过渡模式;低路堤桩承式路堤宜调整桩土截面尺寸以提高相对填料高度H/(s-a),使得路堤变形进入等沉面模式。
[Abstract]:In order to understand the evolution law of pile bearing embankment deformation type and soil arch effect with soil subsidence between piles, and to provide reference for parameter selection, a multi-settlement door test device which can consider the interaction of multiple elements of pile-supported embankment is developed. Considering the height of packing, the net distance between piles s-a and the parameter of pile diameter a, a group of soil arch evolution model tests with soil sinking between piles were carried out. The elliptical steel bar similar soil is used as the filler, and the plane strain test with sand filler is simplified to two dimensional test conditions, which eliminates the influence of the friction force of the front and rear baffles. Through particle image velocimetry technique, the full-field deformation of fillers with soil subsidence between piles was obtained, and the pile-soil load distribution on the bottom surface of fillers was accurately measured by self-made load plate. The deformation types of soil arch of pile-supported embankment and the variation law of pile-soil stress ratio under different parameters are obtained, and the applicable conditions of three kinds of evolution models are summarized by using the test results. The results show that the steel bar similar soil can well simulate the plane stress-strain characteristics of practical sand fillers. There are two main evolution modes of the soil arch effect of pile-supported embankment, which are triangular expansion model and equal-settlement surface type, which are compared with the triangular expansion model. There is no differential settlement on the surface of the equal-settlement embankment, the effect of soil arch is high, and the ratio of pile to soil stress decreases with the settlement of soil between piles. Another type of tower elevation model can be regarded as a transition model from triangular expansion type to equal settlement type, and the pile-supported embankment with low embankment should adjust the size of pile-soil cross-section to increase the relative height of filler H _ (%) -a, and make the embankment deform into the isosettlement mode.
【作者单位】：武汉理工大学土木工程与建筑学院;
【基金】：国家自然科学基金项目(51208403) 武汉理工大学国家级大学生创新创业训练计划资助项目(20151049706038) 湖北省自然科学基金项目(2016CFB469) 武汉市城建委科技计划项目(201639)
【分类号】：U416.12

【相似文献】