节理岩体动态破坏的SHPB相似材料试验研究

采用相似材料模型试验对不同节理倾角、节理贯通度、节理条数、载荷应变率、节理充填物厚度、节理充填物类型及试件长径比等7种工况下的节理岩体动态强度及破坏模式进行了分离式Hopkinson压杆(SHPB)试验研究。结果表明：节理岩体动态破坏模式及强度与节理构造形态密切相关。对于单节理岩体，其强度及破坏特征在很大程度上受节理倾角控制，节理倾角0°、90°试件动强度分别为完整试件的90%和71%，且其破坏形式均为张拉破坏；倾角60°试件动强度几乎为0；倾角30°、45°试件的动强度分别为完整试件的50%和18%，且其破坏以剪切破坏为主，兼有张拉破坏。中心1/4、1/2、4/5及全贯通节理试件的峰值强度分别为完整试件的95%、74% 、28%和17%，即随节理贯通度增加，试件动强度逐渐降低。含1~3条节理的试件动强度分别为完整试件的54%、23%和10%，即随节理条数增加，试件动强度随之有较大幅度降低，但节理条数的增加并没有改变其破坏模式。随着节理充填物厚度增加及节理充填物强度降低，试件强度依次递减，但破坏模式并没有改变。完整试件和节理试件的动强度均随着载荷应变率的增加而变大，且前者对载荷应变率的敏感性要远远高于后者，相应地试件的破坏模式也变得更加复杂。两类试件的动强度均随着试件长径比的增加先增大后减小，即存在一个最佳长径比。

Similar material test study of dynamic failure of jointed rock mass with SHPB

Failure modes of jointed rock mass with different joint dip angles, joint discontinuity degrees, joint sets, load strain ratios, joint filling thicknesses, joint filling types and slenderness ratios under split Hopkinson pressure bar(SHPB) tests are studied by means of similar material model tests. The results show that failure modes and dynamic strength of jointed rock mass are much related to joint configuration. For rock mass with single joint, its strength and failure characteristics are greatly controlled by the joint dip angle. The dynamic strength of the specimens with joint dip angles of 0° and 90°, whose failure modes are both tensile failure, is 90% and 71% of that of intact one, respectively. The dynamic strength of the specimen with joint dip angle of 60° is nearly zero. The dynamic strength of the specimens with joint dip angles of 30° and 45°, whose failure modes are mainly shear failure with partly tensile failure, is 50% and 18% of that of intact one, respectively. The peak strength of the specimens with 1/4, 1/2, 4/5 and 1 joint center continuity degree is 95%, 74%, 28% and 17% of that of intact one, respectively. With increase of joint discontinuity degree, the dynamic strength of specimen decreases. The dynamic strength of the specimens with 1, 2 and 3 groups of joints is 54%, 23% and 10% of that of intact one, respectively. Namely, with increase of joint group, the dynamic strength of specimen decreases greatly; but its failure mode does not change. With increase of joint filling thickness and strength reduction of joint fillings, the dynamic strength of specimen decreases gradually; but its failure mode does not change. The dynamic strength of the intact and jointed specimens both increase with increasing of load strain ratio; and the sensitivity to load strain ratio of the former is much higher than that of the latter, whose failure mode becomes more complicated accordingly. The dynamic strength of these two kinds of specimens both first increase then decrease with the slenderness ratio; that is to say, there exists a best slenderness ratio.