动静组合加载条件下裂隙砂岩力学特性和破坏规律

Mechanical properties and failure laws of sandstone under dynamic and static combined loading conditions

  • 摘要: 为了研究含有交叉裂隙砂岩在动静组合加载条件下的力学特征和裂隙演化损伤规律,采用霍普金森实验系统对含2条不同交叉角度裂隙的砂岩试样进行了一维动静组合加载试验,分析含不同角度裂隙砂岩的动态力学特征、岩体的动态破坏模式。研究结果表明:在动静组合条件下,预制水平裂隙的存在对动态抗压强度的影响远大于预制倾斜裂隙,2条裂隙夹角的增大对砂岩的动态抗压强度有先减小后增大的作用,动静组合加载降低了预制倾斜裂隙对试样强度的影响;随着2条预制裂隙夹角的增大,砂岩的动态抗压强度和动态峰值应变先减小后增大;2条预制裂隙夹角在0°与90°范围内试样以拉伸破坏为主,30°到60°范围内试样以剪切破坏为主,复杂预制裂隙的存在对岩石破坏有规律性影响。

     

    Abstract: In order to study the mechanical characteristics and flaw evolution damage law of sandstone containing cross-flaw under dynamic and static combined loading conditions, a one-dimensional dynamic and static combined loading test was carried out on sandstone specimens with two different cross-flaw angles using the SHPB system. This experiment aimed to analyze the dynamic mechanical properties of sandstone with varying angular flaws and the dynamic damage mode of the rock body. The results showed that under the dynamic and static combination conditions, prefabricated horizontal flaws significantly impacted the dynamic compressive strength more than prefabricated inclined flaws. The increase in the angle between two flaws initially reduced and then enhanced the dynamic compressive strength of the sandstone. The combined loading reduced the influence of inclined flaws on specimen strength. With the increase in the angle of prefabricated flaws, the dynamic compressive strength and dynamic peak-strain of rock decreased first and then increased. The artificial cross-flaw angles of 0° and 90° were mainly dominated by tensile damage, and 30°~60° by shear damage. The existence of complex prefabricated flaws has a regular effect on rock failure.

     

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