单轴压缩条件下裂隙岩样冻融损伤破坏模式分析

Failure modes of fractured rock masses under freeze-thaw action and load

以寒区裂隙岩体为研究对象,采用水泥砂浆类岩石材料制作具有不同几何特征的裂隙岩样,对预制的不同裂隙岩样进行冻融循环试验和单轴压缩试验,研究裂隙长度、裂隙倾角、裂隙数目以及冻融循环次数对试件贯通模式的影响。试验表明:裂隙岩体的几何特征以及冻融循环作用对岩体损伤破坏模式有较大影响。随着冻融循环次数的增加,岩样破裂面的破裂程度越来越严重,破坏模式也越来越复杂;裂隙倾角为30°的裂隙岩样,主要发生拉伸破坏,而裂隙倾角为60°的裂隙岩样,则表现为拉剪贯通,且双裂隙岩样岩桥间多出现压剪裂纹,对于裂隙倾角为90°的岩样,裂隙数目以及裂隙长度对其影响不大,均为劈裂破坏,且破坏面不一定为裂隙面;预制裂隙长度越大,越容易产生除了主拉裂纹以外的支裂纹(压裂纹)。研究结果可为寒区岩体工程建设及运营提供科学的参考。

Taking fractured rock masses as the research object,using rock-like materials produced rock specimens with different geometric characteristics,freeze-thaw experiments and uniaxial compression tests of fractured rock samples have been carried out to investigate the influence of different crack dip angle,crack length,crack number and freezing-thawing cycles on the damage failure modes.The results of the experiments demonstrated that the existence of joint and freezing-thawing cycles have much effect on the damage failure modes.Rock rupture degree becomes more and more serious,and failure modes are becoming more and more complicated with the increase of freeze-thaw cycles; Failure modes of the fractured rock masses are different between single crack and double cracks.Tensile fracture modes often appear when the fissure angle is 30 degrees,mixed modes（shear and compression） take on when the fissure angle is 60 degrees,failure modes present splitting failure when the fissure angle is 90 degrees.The surface of specimens makes more compression cracks besides principal tensile crack with increasing crack length.The above research conclusions can provide valuable references to the constructions and safety operation.