摘要
为揭示冻融循环作用对板岩弹性参数及单轴抗压强度的影响,采用DX-40型低温数控箱、DNS100微型控制电子万能试验机进行7种层理倾角(?)、6种冻融循环次数的单轴压缩试验,对其5个弹性参数、单轴抗压强度及破坏类型的变化规律进行分析。试验结果表明:板岩弹性模量、剪切模量和单轴抗压强度随冻融循环次数增加呈指数下降趋势,泊松比随冻融循环次数增加呈线性增加趋势;板岩单轴抗压强度随层理倾角增加呈先减后增的变化趋势;冻融循环作用下板岩破坏类型有3种:当0°≤?≤26.6°时,沿与竖直轴线呈一定角度方向发生剪切破坏;当26.6°≤?≤83.0°时,沿层理面发生剪切破坏;当83.0°≤?≤90°时,沿垂直方向发生劈裂破坏。在Jaeger单弱面理论的基础上,建立了以冻融循环次数和层理倾角为控制变量的板岩单轴抗压强度预测模型,并通过试验数据验证了模型的合理性,表明该模型能较好地描述冻融循环次数和层理倾角对冻融板岩单轴抗压强度的影响。
To reveal the effect of freeze-thaw cycle on elastic parameters and uniaxial compressive strength of slate, uniaxial compression tests were conducted on slate specimens with seven types of bedding angles under six types of freeze-thaw cycle. The DX-40 low-temperature control box and DNS100 miniature control electronic universal testing machine were applied for tests. We analyzed evolution laws of five elastic parameters, uniaxial compressive strength, and failure forms. Experimental results showed that the elastic modulus, shear modulus, and uniaxial compressive strength decreased exponentially with increasing the number of freeze-thaw cycles. While Poisson＇s ratio increased linearly with increasing the number of freeze-thaw cycles. Particularly, the uniaxial compressive strength firstly decreased and then increased with increasing bedding angle. It is found that there are three kinds of failure forms under uniaxial compressive stress. When the bedding angle was 0° ≤β≤26.6° , shear failure occurred with a certain angle from the vertical axis. When the bedding angle was 26.6°≤β≤83.0° , shear failure occurred along the bedding plane. When the bedding angle was 83.0°≤β≤90°, splitting failure occurred along the vertical direction. On the basis of the single discontinuity theory proposed by Jaeger, an empirical formula of uniaxial compressive strength was established and further verified by experimental data, in which bedding angles and the number of freeze-thaw cycles were considered as control variables. Therefore, the effects of the number of freeze-thaw cycles and bedding angles on compressive strength of freeze-thawed transversely isotropic rock can be well simulated by the model.
作者
傅鹤林
张加兵
黄震
黄宏伟
史越
FU He-lin ZHANG Jia-bing HUANG Zhen HUANG Hong-wei SHI Yue(School of Civil Engineering, Central South University, Changsha, Hunan 410075, China National Engineering Laboratory for Construction Technology of High Speed Railway, Central South University, Changsha, Hunan 410075, China Key Laboratory of Geotechnical and Underground Engineering of the Ministry of Education, Tongji University, Shanghai 200092, China Department of Geoteehnical Engineering, Tongji University, Shan~,hai 200092. China~)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2017年第8期2203-2212,共10页
Rock and Soil Mechanics
基金
国家自然科学基金项目(No.51578550
No.51538009)
中南大学研究生自主探索创新项目(No.2017zzts153)~~
关键词
板岩
冻融循环
层理倾角
弹性参数
单轴抗压强度
破坏类型
slate
freeze-thaw cycles
bedding angle
elastic parameters
compressive strength
failure forms
