工程科学与技术2025，Vol.57Issue(3)：82-95,14.DOI:10.12454/j.jsuese.202300681
循环荷载下圆砾的宏观动力特性及其细观模拟
Macroscopic Dynamic Characteristics and Microscopic Simulation of Round Gravel Under Cyclic Loading
摘要
Abstract
A series of saturated undrained dynamic triaxial tests are conducted using the DYNTTS large-scale triaxial cyclic test system,and a dis-crete element(DEM)undrained dynamic triaxial model is established based on indoor experiments to explore the evolution of macroscopic dy-namic properties and the internal microstructural dynamic response of round gravel under subway cyclic loading.The macroscopic dynamic char-acteristics of the round gravel and the internal microscopic parameter response law under different relative densities,confining pressures,and dy-namic stress amplitudes are analyzed.The results show that when the confining pressure is small(σ3=100 kPa)and the relative density is low(Dr=0.3),the accumulated plastic strain of the round gravel is too large(greater than 0.61％),posing a severe safety hazard for train operation.When the confining pressure is higher(σ3=200,300 kPa),the cumulative plastic strain is smaller(less than 0.14％),indicating relatively safe train opera-tion.The greater the relative density and confining pressure,the lower the cumulative plastic strain of the specimen,the higher the resilient modu-lus,and the lower the energy consumption inside the specimen.Therefore,extrusion measures such as high-pressure grouting are considered to improve the relative compactness of the soil to reduce the settlement of the subway foundation.During the cyclic loading process,both the coordi-nation number and anisotropy change periodically.The direction of change in coordination number is opposite to that of cyclic loading,while the direction of change in anisotropy aligns with cyclic loading.With the increase in relative density and confining pressure,the coordination number becomes larger and the anisotropy becomes weaker.With the increase in dynamic stress amplitude,the coordination number decreases and the an-isotropy increases.The strong contact is mainly controlled by the axial stresses,which play a significant role in bearing capacity.The research re-sults provide a reference for the design and safe operation of subway lines on round gravel foundations.关键词
循环荷载/圆砾/动力特性/离散元Key words
cyclic loading/round gravel/dynamic characteristics/discrete element分类
建筑与水利引用本文复制引用
马少坤,田发派,黄海均,马敏,何本富,段智博..循环荷载下圆砾的宏观动力特性及其细观模拟[J].工程科学与技术,2025,57(3):82-95,14.基金项目
国家自然科学基金项目(52268062) （52268062）
广西自然科学基金重点项目(2020GXNSFDA238024) （2020GXNSFDA238024）
广西重点研发计划项目(GUIKEAB22080061) （GUIKEAB22080061）
广西交通运输行业重点科技项目(GXJT-2020-02-08) （GXJT-2020-02-08）
