摘要
研究以中国西北地区近年来黄土路基滑坡为背景.通过击实试验和直剪试验,测得不同地聚物掺量下固化土的试验数据,并通过扫描电镜(SEM)和X射线衍射(XRD)对钢渣-粉煤灰地聚物固化土进行微观结构分析,同时结合pF-Meter仪器测定不同地聚物掺量下固化土的基质吸力与体积含水率.后基于强度折减法,将试验数据代入COMSOL Multiphysics中,通过饱和-非饱和理论的Richards方程,建立固化黄土路基边坡有限元模型.分析降雨前后路基层中地聚物掺入量和坡比对路基边坡的整体稳定性的影响.结果表明:当固化土中地聚物掺入量为25%时,内摩擦角为31.2°,内摩擦角增幅相比于重塑黄土提高了62.5%.随着地聚物掺入量的增加,黏聚力呈现出先升后降的趋势,当地聚物掺入量为20%时达到最高峰,为81.09 kPa,相比于重塑黄土提高了75.86%.路基边坡的稳定性随着地聚物掺入量的增加先上升后下降,随着坡比减小而上升.在特定条件下,边坡稳定性会随着降雨时间的延长而降低,随着降雨强度的增大而减小.
The research background focused on the occurrence of loess roadbed landslides in northwest China in recent years.The test datas of solidified loess with different geopolymer content were measured through compaction and direct shear tests.Additionally,the microstructure of steel slag-fly ash geopolymer solidified loess was examined using the scanning electron microscope(SEM)test and X-ray diffraction(XRD)test,and the pF-Meter instrument was used to measure the matrix suction and volumetric moisture content of the solidified loess with different geopolymers content.The test datas were then imported into COMSOL Multiphysics based on the strength reduction method,and the finite element model of the solidified loess roadbed slope was created using the Richards equation of the saturated-unsaturated theory.The impact of geopolymer content and slope ratio in the roadbed layer on the overall stability of the roadbed slope before and after rainfall was analyzed.The results indicate that when the solidified loess contains 25%geopolymer,the internal friction angle increases by 62.5%compared to reshaped loess,reaching 31.2°.The cohesion exhibits a trend of initially increasing and then decreasing as the geopolymer content increases.The highest peak is reached at 81.09 kPa when the geopolymer content is 20%,which is 75.86%higher than the cohesion of reshaped loess.The stability of the roadbed slope initially increases and then decreases with an increase in geopolymer content,while it increases with a decrease in slope ratio.Under specific conditions,slope stability decreases with prolonged rainfall duration and reduces with higher rainfall intensity.
作者
唐先习
李昊杰
李明泽
王之鲁
TANG Xianxi;LI Haojie;LI Mingze;WANG Zhilu(School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China;China Railway Lanzhou Group Co.,Ltd.,Lanzhou 730000,China)
出处
《湖南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2024年第9期133-144,共12页
Journal of Hunan University:Natural Sciences
基金
国家自然科学基金资助项目(11962016)
中国铁路兰州局集团有限公司资助项目(LTKY2023036-1)。
关键词
地聚物
有限元法
边坡稳定性
滑坡
固化黄土
geopolymers
finite element method
slope stability
landslides
solidified loess
