基于粗颗粒动态演化过程的高铁填料振动压实机理研究  

Vibration compaction mechanism of high-speed railway fillers based on dynamic evolution of coarse particles

作　　者：谢康 陈晓斌[1] 尧俊凯 李泰灃 王业顺 邓志兴 吕鑫龙 XIE Kang;CHEN Xiaobin;YAO Junkai;LI Taifeng;WANG Yeshun;DENG Zhixing;LÜXinlong(College of Civil Engineering,Central South University,Changsha 410075,China;Railway Engineering Research Institute of China Academy of Railway Sciences Corporation Limited,Beijing 100081,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中国铁道科学研究院集团有限公司铁道建筑研究所,北京100081

出　　处：《岩土工程学报》2024年第4期803-813,共11页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51978674);中国国家铁路集团有限公司科技研究开发计划项目(P2021G053);中国铁道科学研究院集团有限公司基金项目(2021YJ071);中南大学研究生创业计划项目(2022ZZTS0622)。

摘　　要：为了揭示高铁粗粒土填料振动压实机理,以典型的高铁基床表层级配碎石填料为研究对象,首先基于自行研制的大型振动压实仪,建立连续干密度ρ_(rd)、动刚度Krb以及修正地基系数K20的压实质量评估体系;然后利用X-CT对压实过程中的级配碎石进行扫描,从粗颗粒动态演化角度揭示级配碎石的压实机制。研究结果表明:整个压实过程中,不同土体类型的级配碎石ρ_(rd)均呈现出急速上升-缓慢上升的趋势,而Krb和K20却呈现出急速上升-缓慢下降的趋势。进一步,提出压实嵌锁点Tlp以量化出级配碎石的压实性能拐点特征。振动压实过程中当60%的粗颗粒长轴趋于水平排布时(处于Tlp状态),即呈现出振动压实稳定态;而后进一步压实,易导致粗颗粒发生以表面研磨为主的破碎现象,破坏骨架稳定性,降低压实性能。最终通过离散元模拟验证该机制的正确性。研究成果可从细观层面揭示振动压实机理,为高铁智能碾压质量评估提供新的方法。In order to reveal the mechanism of vibration compaction for high-speed railway fillers,a series of typical graded gravel fillers which belong to the surface layer of the subgrade are used to the investigation object.Firstly,an evaluation system for the compaction quality assessment indices of continuous dry density ρ_(rd),dynamic stiffness rbK and modified foundation coefficient 20K is established based on the self-developed vibration compaction apparatus.Secondly,the graded gravel was scanned by X-CT during the vibratory compaction.The compaction mechanism of graded gravel was revelad based on the the dynamic evolution of coarse particles.The results show that ρ_(rd)of the graded gravel fillers exhibits a rapid rise-slow rise tendency.However,rbK and K20 present a rapid rise-slow downward tendency.Moreover,the compaction locking point lpT is proposed to quantify the inflection point of graded gravel fillers during the vibration compaction.During the vibration compaction process,the stability of vibration compaction occurs when 60%of the coarse particles tend to be horizontally arranged in the long axis(lpT state).And then further compaction results in the occurrence of surface grinding-based crushing phenomenon of coarse particles to destroy the skeleton stability.Finally,the validity of the mechanism is verified through the discrete element simulation.The research results can reveal the vibration compaction mechanism from the fine view level and provide a new method for the intelligent rolling quality assessment of high-speed railways.

关 键 词：高铁路基 级配碎石 压实机理 X-CT 动态演化 量化表征 

分 类 号：TU43[建筑科学—岩土工程]