摘要
基于TSZ-3型应变控制式三轴剪切仪,在不同固结围压条件下对不同压实度粉煤灰-石灰改良黄土和压实黄土进行了常规三轴加载试验,研究了竖向加载条件下改良黄土和压实黄土的应力-应变演化关系、强度特性及其破坏方式的差异。研究结果表明:改良黄土的应力-应变曲线以软化型为主,屈服即意味着破坏;压实黄土全部为应变硬化型,可用双曲线描述,属于渐进屈服破坏。固结围压和压实度均会对压实和改良黄土的强度产生较大影响,两者之间的耦合关系共同决定黄土的强度。改良黄土的黏聚力值均远大于压实黄土,内摩擦角略微大于压实黄土;改良黄土在剪切前期强度增长较大,压实黄土的强度随着剪切变形的发展逐步发挥。三轴竖向加载条件下,改良黄土呈脆性滑移破坏形式,压实黄土呈剪缩侧胀破坏。
The TSZ-3 strain-controlled triaxial shear apparatus was applied to test the strength difference of fly ash-lime improved loess and compacted loess.In order to study their stress-strain evolution relationship,strength characteristic and failure mode,vertical loading triaxial tests with various compacting degree were conducted under different confining pressures.The results show that the stress-strain relationship curve of improved loess is mainly of softening type,yielding means failure.The stress-strain relationship curve of compacted loess is hardening type and belongs to progressive yield failure.It can be described by hyperbolic curve.Both the confining pressure and compacting degree have significant effects on the strength of the improved loess and compacted loess,the coupling relationship between the two determines the strength of the loess together.The cohesion value of improved loess is much bigger than that of the compacted loess,while the internal friction angle of improved loess is slightly bigger than that of the compacted loess.The strength of improved loess increases greatly in the early shearing period,and the compacted loess strength develops gradually with the development of shear deformation.Under the condition of triaxial vertical loading,the modified loess presents brittle slip failure modes,while the compacted loess shows shear dilatation and lateral dilation failure modes.
作者
张玉
何晖
曾志英
刘瑾
丁潇
杨倩
ZHANG Yu;HE Hui;ZENG Zhi-ying;LIU Jin;DING Xiao;YANG Qian(Civil and Architecture Engineering,Xi’an Technological University,Xi’an 710021,China;Shaanxi Key Laboratory of Loess Mechanics and Engineering,Xi’an University of Technology,Xi’an 710048,China)
出处
《科学技术与工程》
北大核心
2021年第8期3265-3273,共9页
Science Technology and Engineering
基金
国家自然科学基金(11802218)
陕西省科技计划项目(2019JQ-432)
陕西省黄土力学与工程重点实验室项目(LEM201801)
陕西省教育厅专项科研计划项目(20JK0670)。
关键词
粉煤灰-石灰
改良黄土
压实黄土
应力-应变关系
强度特性
fly ash-lime
improved loess
compacted loess
stress-strain relation
strength characteristics
