平行双裂隙类石灰岩试样注浆前后的力学特性和开裂行为

Mechanical properties and cracking behaviors of limestone-like samples with two parallel fissures before and after grouting

本文对几何形态不同的张开平行双裂隙类石灰岩试样和水泥充填平行双裂隙类石灰岩试样进行了单轴压缩试验,发现试样的力学特性和开裂行为受岩桥角度和裂隙倾角的影响。通过分类,总结了四种岩桥贯通方式。在观察试验过程中发现在裂隙倾角较小的试样中,加载前期产生的张裂纹在加载过程中会闭合,这是一个未被提及的新现象。结果表明,张开裂隙试样和水泥充填裂隙试样的峰值强度、起裂应力和聚结类型不同,产生这种现象的原因是水泥灌浆可以传递应力,从而减少裂隙尖端和岩桥区域的应力集中。

In the present work,uniaxial compressive tests were carried out on limestone-like samples containing two parallel open fissures or cement-infilled fissures with different geometries.Mechanical property and crack behavior of limestone-like samples with two parallel open fissures or cement-infilled fissures were affected by bridge inclination angle and fissure inclination angle.Four types of coalescence of rock bridge for samples containing open fissures or cement-infilled fissures were summarized and classified.The closure of tensile crack was observed in the samples with small fissure inclination angle.This is a new phenomenon which is not mentioned in previous studies.Test results show that the peak strength,crack initiation stress,and coalescence type are different between open fissures and cement infilled fissures.The reason for this phenomenon is that grouting of cement can transfer stress and reduce stress concentration at the flaw tip and rock bridge area.