岩石亚临界裂纹扩展及其应用研究

Subcritical Crack Growth of Rocks and Its Applications

亚临界裂纹扩展是岩体工程破坏时间效应的原因之一。应力腐蚀机制能很好地说明亚临界裂纹的扩展,其中适合岩石材料的应力腐蚀理论是Charles理论。利用双扭试件可获得岩石亚临界裂纹扩展Charles理论的相关参数。将传统断裂力学中拉伸应力和压剪应力下的裂纹扩展模型与Charles理论相结合,推导出与时间相关的裂纹扩展模型。采用双扭试件测得了中条山有色金属集团某矿矿岩的亚临界裂纹扩展参数。将此参数应用于拉伸应力下与时间相关的裂纹扩展模型,预测矿岩崩落时间,结果表明:该模型能较好地预测矿体的崩落;同时,也可为其他岩体工程的施工开挖提供指导。压剪应力下与时间相关的裂纹扩展模型的应用及复杂状态下多裂纹相互影响的扩展模型,有待进一步研究。

Subcritical crack growth is one of the main causes of time-induced failure in rock engineering. It can be explained by the stress corrosion mechanism and Charles theory is a stress corrosion theory suitable for rocks. Double torsion tests are often used for the subcritieal crack growth in rocks and the parameters in Charles theory can be obtained. The crack propagation models under the tensile stress and compression-shear stress in the traditional fracture mechanics are combined with Charles theory, which would lead to the time- dependent crack propagation models. The subcritical crack growth parameters of ore-rock in ZTS Non-ferrous Metals Group were obtained by double torsion tests and applied to the time-dependent crack propagation model under the effect of tensile stress to predict ore-rock block caving. It is found that the ore block caving can be predicted accurately. Additionally, the excavation construction of rock projects can be guided by the model. The application of the time-dependent crack propagation model under compression-shear stress and the time-dependent crack propagation model of multiple cracks interaction under complex conditions remain to be further studied.