摘要
为了研究多次高温水冷产生的热冲击作用对花岗岩力学性能、开裂特征的影响,将花岗岩在300℃高温下进行不同循环次数的高温水冷热冲击处理,并对处理后的花岗岩分别开展静态压缩试验与静态巴西劈裂试验,测试其相关力学参数的变化。结果表明:(1)随着循环热冲击次数的增加,花岗岩的抗压强度、抗拉强度都呈现下降趋势,且抗压强度与抗拉强度之间存在线性函数关系,根据拟合公式,可以较好地预测花岗岩的强度变化特征。(2)花岗岩的压缩弹性模量、变形模量经过15次循环热冲击后,分别下降了25.18%、35.20%;拉伸弹性模量下降了46.76%,采用多项式拟合结果较好。(3)随着循环热冲击次数的增加,花岗岩延性增加,表现为单轴压缩应力-应变曲线形式从塑-弹性形式向塑-弹-塑性形式过渡;巴西劈裂试验应力-应变曲线基本分为压密阶段、弹性变形阶段和峰后破坏3个阶段。(4)花岗岩单轴压缩破裂模式从竖向劈裂破坏逐渐向锥形剪切破坏过渡,破坏角度逐渐减小。可见循环高温水冷热冲击对花岗岩力学性能的劣化具有较大的影响。
In order to study the effect of thermal shock caused by multiple high-temperature water cooling on the mechanical properties and cracking characteristics of granite,the granite was subjected to high-temperature water-cooling thermal shock treatment with different cycles at a high temperature of 300℃,and the static uniaxial compression test and static Brazilian splitting test were carried out on the treated granite to test the changes of related mechanical parameters.The results show that with the increase of the number of cyclic thermal impact,both the compressive strength and tensile strength of granite show a downward trend,and there is a linear function relationship between the compressive strength and tensile strength.According to the fitting formula,it can be better predict the strength change of granite.The compressive elastic modulus and deformation modulus of granite decreases by 25.18%and 35.20%respectively after 15 cycles of thermal shock.The tensile elastic modulus decreases by 46.76%,and the result of polynomial fitting is better.With the increase in the number of cyclic thermal shocks,the ductility of granite increases,which is manifested as the transition from plastic-elastic to plastic-elastic-plastic form of uniaxial compression stress-strain curve.The Brazil split test stress-strain curve can be divided into three stages:compaction stage,elastic deformation stage and post-peak failure.The fracture mode of granite under uniaxial compression gradually transitions from vertical splitting failure to conical shear failure,and the failure angle gradually decreases.It can be seen that the thermal shock of circulating high temperature water cooling has a great influence on the deterioration of the mechanical properties of granite.
作者
彭海旺
余莉
PENG Hai-wang;YU Li(College of Civil Enginceering and Architecture,Hebei University,Baoding 071002,China)
出处
《科学技术与工程》
北大核心
2021年第13期5432-5439,共8页
Science Technology and Engineering
基金
河北省高等学校科学技术研究项目(BJ2018046)
河北大学研究生创新创业项目(hbu2020ss027)
神狐海域天然气水合物先导试验区试采实施(DD20190228)。
关键词
花岗岩
热冲击
单轴压缩
巴西劈裂
力学性质
granite
thermal shock
uniaxial compression
Brazilian splitting
mechanical properties
