类岩石裂隙扩展多因素影响研究

Experimental study on the influence of many factors on crack propagation of rock-like specimen

岩体强度是影响岩体工程安全的重要因素,其会因多种因素的改变而变化,研究不同因素对裂隙扩展的影响,可以获得不同因素对岩体强度影响规律,为保证岩体工程的安全和稳定提供参考依据。文章主要考虑节理位置、围压和温度对岩体破裂过程的影响,通过室内试验分析节理位置对岩体裂隙扩展规律的影响,研究围压的改变对岩体峰值强度和破裂形态的作用,通过加卸载试验定性分析了洞室开挖掌子面的卸荷效应,并对4种较低温度和3种超高温度下岩体的裂隙扩展形态和规律进行了研究。结果表明:节理位于试件端部时,以翼裂纹扩展为主、次生裂隙扩展为辅,主要产生张拉裂纹,而节理位于试件中间时,主要产生剪切裂纹;围压的增加会提高岩体的强度,抑制裂纹的扩展,岩体卸载容易产生劈裂破坏;温度能够降低岩体的强度,超高温条件下,岩体易产生炸裂。

The strength of rock mass is an important factor affecting the safety of rock mass engineering,and the strength of rock mass will change with the change of many factors.By studying the influence of different factors on crack propagation,the law of influence of different factors on rock mass strength is obtained,which can provide reference for ensuring the safety and stability of rock mass engineering.The influence of joint location,confining pressure and temperature on rock masses’cracking process are considered in this paper.Through laboratory tests,the influence of joint location on crack propagation of rock mass is analyzed;the effect of confining pressure on the peak strength and fracture morphology of rock mass is studied;the unloading effect on the palm face of excavation is analyzed by loading and unloading test,finally,the crack propagation patterns and laws of rock mass under four kinds of lower temperatures and three kinds of higher temperatures are studied.The results show that,when the joint is located at the end of the specimen,the wing crack propagation is dominant,the secondary crack propagation is supplementary,and most are the tensile cracks;when the joint is located in the middle of the specimen,most are the shear cracks.The confining pressure increases,the strength of rock mass will increase while the crack propagation will be restrained.Temperature can reduce the strength of rock mass,and it is easily to burst under ultra-high temperature.