摘要
根据上、下限定理,基于MATLAB编制有限元极限分析程序,并采用修正的Hoek-Brown准则计算下伏溶洞路堤极限承载力;在此基础上,探讨上覆土层荷载、溶洞跨度、高度、旋转角度、路堤荷载与溶洞水平距离、岩层顶面与溶洞垂直距离、岩层物理力学参数对路堤承载力的影响。结果表明:上覆土层荷载、溶洞高度及岩层重度对路堤承载力的影响可忽略不计,路堤承载力随溶洞跨度的增大而减小,随路堤荷载与溶洞水平距离、岩层顶面与溶洞垂直距离的增大而增大,当溶洞旋转角度小于60°时,可不考虑旋转角度的影响。本文从溶洞各参数对极限破坏模式的影响展开讨论,极限破坏模式主要有溶洞顶板的冲切破坏,溶洞侧壁发生破坏,溶洞顶板冲切和侧壁的联合破坏,溶洞顶板冒落和侧壁的联合破坏等;最后通过计算无溶洞时路堤的极限承载力,与已有研究成果进行对比,验证了本文所提方法的正确性。
According to the upper and lower bound theorems,the limit program of finite element analysis is compiled based on MATLAB,and the modified Hoek-Brown criterion is used to calculate the ultimate bearing capacity of embankment.The effects of loading of overlaying soil,the cave span,height,rotation angle,horizontal distance between embankment load and cave,vertical distance between the top of the rock and cave,and material parameters on ultimate bearing capacity of embankment are investigated.The results reveal that the effects of load of overlaying,the cave height and rock unit weight on ultimate bearing capacity of embankment can be neglected.The ultimate bearing capacity decreases with the increase of the cave span,the horizontal distance between the cave and subgrade load and the vertical distance between the cave and the top of the rock.The cave rotation has a negligible effect on the ultimate bearing capacity when the value of the cave rotation exceeds 60°.The influence of various parameters about cave on the ultimate failure mode is discussed.There are several ultimate failure modes such as:roof punch failure,side wall failure,combined roof punch and side wall failure,and combined roof falling and side wall failure.At last,the method proposed in this paper is verified by comparing the ultimate bearing capacity of embankment with no karst cave with the existing research results.
作者
陈言章
赵明华
CHEN Yan-zhang;ZHAO Ming-hua(Guangdong Architectural Design and Research Institute Co.,Ltd.,Guangzhou 510010,China;Institute of Geotechnical Engineering,Hunan University,Changsha 410082,China)
出处
《地基处理》
2021年第2期100-109,共10页
Journal of Ground Improvement
基金
国家自然科学基金项目(51478178)。
关键词
溶洞
路堤
承载力
有限元
极限分析
karst cave
embankment
bearing capacity
finite element
limit analysis
作者简介
陈言章(1993-),男,福建宁德人,硕士,主要从事道路设计及软土地基处理等研究。E-mail:739688350@qq.com。
