高温作用下角砾岩动态力学特性研究

Study on dynamic mechanical properties of breccia at high temperatures

为了解高温作用下角砾岩动态力学特性,开展了不同温度、不同加载速率下的角砾岩动态冲击实验。试样为取自云南卡房地区的天然角砾岩,将试样加热到200、400、600、800℃并采用3种加载速率(7.8、9.8、11.8 m/s)进行霍普金森冲击实验,结果表明:随着温度的升高,温度对于角砾岩动态抗压强度有着先强化后弱化的作用,在400℃时抗压强度达到峰值,相较常温(25℃),3种加载速率下抗压强度的增幅分别为42.8%、24.3%、18.1%;应变率和峰值应变呈线性增加,破坏程度与抗压强度随温度的变化规律一致。

In order to understand the dynamic mechanical characteristics of breccia at high temperatures,dynamic impact tests of breccia at different temperatures and loading rates were carried out.The samples were taken from natural breccia deposit in Kafang area,Yunnan Province.As the sample was heated to 200℃,400℃,600℃and 800℃separately,for each stage of temperature the Hopkinson impact tests were performed at loading rates of 7.8 m/s,9.8 m/s and 11.8 m/s respectively.The results show that as the temperature was rising,the dynamic compressive strength of breccia went up firstly and then dropped.It reached the peak at 400℃,and was 42.8%,24.3%and 18.1%respectively higher than that at room temperature(25℃)at above loading rates.The strain rate and peak strain increased linearly,while the breakage and compressive strength varied with the temperature.