饱水及高温对砂岩声学力学性质影响试验研究

对砂岩经历饱水及不同温度(25~1 000 ℃)前后的物理参数、纵波波速及力学性能参数进行了量测,分析了砂岩试样的密度变化率,纵波波速的变化规律,抗压强度、抗拉强度的变化及压缩破坏形态的差异。结果表明砂岩在经历饱水、高温后内部微裂隙发展,使结构致密性下降,超声波速降低;经历不同温度后砂岩波速的变化率与温度等级近似呈线性关系;800~1 000 ℃之间存在一个温度阀值,高于此温度后砂岩的密度、纵波波速、强度都急剧降低;温度的不同也会影响砂岩的破坏形态,200~800 ℃范围内及饱水后砂岩的破坏模式基本为剪破坏,25~100 ℃范围内破坏模式为张破裂。基于试验结果结合砂岩材料的微观结构特征对温度和饱水作用下砂岩各方面性质的变化进行了机理分析,结果可为实际岩体工程提供一定参考。

Experimental Study on Ultrasonic and Mechanical Properties of Sandstone Influenced by Water-saturation and High Temperature

Physical parameters, ultrasonic velocities and mechanical properties of sandstone that experienced water-saturation and different temperature(25~1 000 ℃)are measured, analysis on the density rate, the change of ultrasonic velocities, the change of compressive and tensile strength, the failure modes of sandstone was carried out. Results show that the cracks of sandstone specimens that experienced water-saturation and high temperature develop so that the compactness and ultrasonic velocities of specimens decline. Velocity change rate versus temperature curve of sandstone specimens is nearly linear relationship. There is a turning point temperature between 800~1 000 ℃, after that the density, ultrasonic velocities and strength drastically reduced. Sandstones having experienced different temperature have different failure modes, between 200~800 ℃ and after water-saturation the failure modes is shear failure, between 25~100 ℃ is tensile failure. Based on the experimental results with combining the microstructure characteristics, an analysis on the sandstone’s change mechanism after water-saturation and high temperature was carried out, the conclusions can provide references for rock engineering.