静动荷载下桩网结构路基土工格栅承载特性试验研究  

Experimental Study on Bearing Behavior of Geogrid in Pile⁃supported Reinforced Embankment Under Static and Dynamic Load

作　　者：梁自立 王旭[1] 韩高孝[1] LIANG Zili;WANG Xue;HAN Gaoxiao(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]兰州交通大学土木工程学院,兰州730070

出　　处：《铁道建筑》2023年第9期135-140,共6页Railway Engineering

基　　金：国家自然科学基金(41902272,51868038)。

摘　　要：以京沪高速铁路徐沪段路基为研究对象,通过室内大比例模型试验,研究了静动荷载作用下桩网结构路基土拱效应与土工格栅承载性能的变化规律,分析10万次动荷载作用后土工格栅的承载特性。结果表明:在路基填筑初期未形成稳态土拱前土工格栅应变增长较快,当形成稳态土拱后土工格栅应变增长趋于稳定,且桩帽边缘处土工格栅应变增长最快,土工格栅使得桩顶上方多承担了7.6%的荷载;10万次动荷载作用下,土拱效应依然有效,但是会产生一定程度的弱化,土工格栅减小了动荷载对土拱效应的削弱作用;相比静载动荷载作用下土工格栅应变增长迅速,最大增长了约19%;动荷载作用后土工格栅会产生拉力退化与软化现象。Taking the subgrade of Xuzhou-Shanghai section of Beijing-Shanghai high speed railway as the research object.Through large-scale indoor model tests,the variation patterns of the arching effect of pile-supported reinforced embankment and bearing performance of geogrids under static and dynamic loads were studied.The bearing characteristics of geogrids after 100,000 cycles of dynamic load were analyzed.The results show that the strain of the geogrid increases rapidly before the formation of a stable soil arch in the initial stage of subgrade filling.After the formation of a stable soil arch,the strain of the geogrid tends to stabilize,and the strain of the geogrid increases the fastest at the edge of the pile cap.The geogrid could cause an additional load of 7.6%to be borne above the pile top.Under 100,000 dynamic loads,the soil arching effect is still effective,but it will weaken to a certain extent.The geogrid could reduce the weakening effect of dynamic loads on the soil arching effect.Compared with the static load,the strain of geogrids under dynamic load increases rapidly,with a maximum increase of about 19%.Geogrid will experience tension degradation and softening phenomena after being subjected to dynamic loads.

关 键 词：桩网结构路基 动荷载 土拱效应 土工格栅 格栅应变 拉伸试验 

分 类 号：U213.1[交通运输工程—道路与铁道工程]