摘要
高液限土边坡在降雨历时、雨后多呈浅层破坏工况。为探明不同干湿循环条件对原状高液限花岗岩残积土微观结构的影响,选取惠龙高速高液限土原状样开展干湿循环及扫描电镜试验,探究干湿循环作用前后原状高液限花岗岩残积土微观结构变化,定量分析定向度、丰度、面积孔隙率与面积孔隙比、等效直径、平均圆形度等微观特征参数变化规律。结果表明:干湿循环作用对高液限花岗岩残积土的损伤效应在微观上表现为孔隙裂隙的扩张,整体孔隙率增大;片状颗粒破碎严重,颗粒尺寸变小,原先较大的团粒分散成了更小的团粒,粒间黏聚力降低;颗粒不断向长扁状演化。该结果可为干湿循环作用下高液限花岗岩残积土强度衰减机制及边坡失稳破坏机理提供一定理论依据。
In view of the fact that the slope of high liquid limit soil usually shows shallow failure conditions during and after rainfall,in order to explore the influence of undisturbed high liquid limit granite residual soil on the microstructure under different dry-wet cycle conditions,the undisturbed high liquid limit granite residual soil samples of Huilong highway with high liquid limit are selected to carry out dry-wet cycle and scanning electron microscope tests and to explore the changes of microstructure of undisturbed granite residual soil with high liquid limit before and after dry-wet cycles.In addition,the variation rules of microscopic characteristic parameters such as orientation,abundance,area porosity and area porosity ratio,equivalent diameter,and mean roundness are quantitatively analyzed.The results show that the damage effect of dry-wet cycles on the granite residual soil with high liquid limit is the expansion of pore cracks and the overall porosity increases,the flake particles are broken seriously,the particle size becomes smaller,the originally larger aggregates are dispersed into smaller aggregates,the cohesion between grains decreases,and the grains continuously evolve into long flat shapes.The experimental results can provide a theoretical basis for the strength attenuation mechanism of granite residual soil with high liquid limit and the failure mechanism of slope under the action of dry-wet cycles.
作者
刘伟明
张华涛
常锦
胡林杰
向家骏
LIU Weiming;ZHANG Huatao;CHANG Jin;HU Linjie;XIANG Jiajun(Guangdong Honggao Construction Group Co.LTD,Dongguan Guangdong 523123,China;School of Civil Engineering,Changsha University,Changsha Hunan 410022,China;School of Transportation Engineering,Changsha University of Science&Technology,Changsha Hunan 410114,China)
出处
《长沙大学学报》
2023年第2期42-47,53,共7页
Journal of Changsha University
基金
国家自然科学基金项目,编号:52107166
湖南省教育厅优青项目,编号:22B0825。
关键词
路基边坡
高液限土
干湿交替
微观特征
强度衰减
subgrade slope
high liquid limit soil
dry-wet cycle
microscopic features
attenuation of strength
