变化温度下岩石混凝土界面剪切损伤特征

Shear Damage Characteristics of Rock-Concrete Interface at Change of Temperature

环境温度变化改变了隧洞围岩与衬砌界面的力学性能,直接影响着衬砌结构的承载特性和隧洞围岩的安全稳定性。通过设计三种变温养护模式干预方案,进行混凝土单轴压缩和岩石混凝土直剪试验,获得不同温度变化干预下混凝土应力-应变曲线和岩石混凝土界面剪切应力-位移曲线,分析变化温度干预下岩石混凝土力学性能、相对刚度及界面剪切损伤演化速率的变化规律。结果表明,初始干预温度越高,界面抗剪强度峰值和剪切刚度越大、岩石混凝土相对刚度越大、界面峰后剪切脆性越好、界面剪切损伤演化速率越大,初始干预温度的影响占主导地位;岩石混凝土相对刚度与界面剪切损伤演化速率呈正相关关系。相关研究成果可为高地温及变温环境下隧洞衬砌结构承载性能评价提供理论支撑。

The change of environment temperature changes the mechanical properties of the interface between surrounding rock and lining of tunnel,which directly affects the bearing characteristics of lining structure and the safety and stability of surrounding rock of tunnel.Three intervention schemes of varying temperature curing modes were designed to carry out the test of uniaxial compression of concrete and direct shear of rock-concrete.The stress-strain curves of concrete and the interface shear stress-displacement curves of rock-concrete under the intervention of different temperature changes were obtained.And then the changing laws of mechanical properties,relative stiffness and interface shear damage evolution rate of rock-concrete under the intervention of varying temperature were analyzed.The results show that the higher the initial intervention temperature is,the greater the interface peak shear strength and shear stiffness is;The greater the relative stiffness of rock-concrete is,the better the post-peak shear brittleness of the interface is,and the greater the interface shear damage evolution rate is.The influence of initial intervention temperature has been dominant.The relative stiffness of rock-concrete has been positively related with the evolution rate of interfacial shear damage.The relevant research results have theoretical support for the bearing performance evaluation of tunnel lining structures under high ground temperature and variable temperature environment.