岩土力学2024，Vol.45Issue(7)：1976-1986,11.DOI:10.16285/j.rsm.2023.1231
含水率对红层泥岩填料刚度劣化特性及微观结构影响研究
Effect of water content on stiffness degradation and microstructure of red mudstone fill material
摘要
Abstract
A series of undrained triaxial shear tests,mercury intrusion porosimetry(MIP)tests,and scanning electron microscopy(SEM)tests were conducted on red mudstone fill material(RMF)at varying water contents to investigate its microstructure and stiffness degradation.Based on the principle of energy conservation,a relationship between the stiffness degradation of the fill material and the increment of elastoplastic strain energy was derived.The results show that the cohesion of RMF decreases with increased water content,while the internal friction angle initially increases and then decreases on the wet side.The evolution of strain energy leads to structural damage and subsequent stiffness degradation.The normalized stiffness ratio linearly decreases with the ratio of plastic strain energy to total strain energy and nonlinearly decreases with normalized shear stress.With optimal water content as the boundary,the RMF exhibits better load-bearing capacity on the dry side,while significantly lower on the wet side.The contours of damage stress and constant water content lines define a state boundary surface,whose upper and lower bounds follow logarithmic curves.The pore size distribution(PSD)of RMF on the dry side exhibits a uni-modal pattern with strong inter-aggregate contacts and good structural stability.On the wet side,however,a bi-modal structure is observed with weaker orientation of aggregates.It is recommended that the fill material be compacted on the dry side,with a target water content ranging from 5％to 7％.关键词
路基填料/红层泥岩/刚度劣化/应变能/微观结构Key words
subgrade fill material/red mudstone/stiffness degradation/strain energy/microstructure分类
建筑与水利引用本文复制引用
陈康,刘先峰,袁胜洋,马杰,陈忆涵,蒋关鲁..含水率对红层泥岩填料刚度劣化特性及微观结构影响研究[J].岩土力学,2024,45(7):1976-1986,11.基金项目
国家自然科学基金资助项目(No.52078432,No.52168066) （No.52078432,No.52168066）
国家青年科学基金资助项目(No.52008355) （No.52008355）
四川省科技计划项目(No.2021YJ0036,No.2021YFH0024) （No.2021YJ0036,No.2021YFH0024）
国家公派留学资助项目(No.202207000096).This work was supported by the Natural Science Foundation of China(52078432,52168066),the Natural Youth Science Foundation of China(52008355),the Science and Technology Program of Sichuan(2021YJ0036,2021YFH0024)and China Scholarship Council(CSC)(202207000096). （No.202207000096）
