含交叉裂隙节理岩体锚固效应及破坏模式

 用相似材料制作含交叉裂隙岩体无锚及加锚试件，以主次裂隙之间角度、锚固位置及锚杆与加载方向之间角度为变化参数制作32组试件，对试件进行单轴压缩试验，研究含交叉裂隙节理岩体的锚固效应及破坏模式。研究表明：在主、次裂隙位置不变的情况下，锚固位置在裂隙交叉点上方或下方时能得到锚固强度最大值，当锚固位置通过裂隙交叉点时，锚固强度不是最大值，但此时锚后试件峰值强度最稳定；大部分含交叉裂隙加锚岩体强度高于含单一裂隙加锚岩体；主、次裂隙夹角影响节理岩体加锚后力学性能，主、次裂隙夹角为30°左右时节理岩体锚固效果最好；锚杆增强了含交叉裂隙节理岩体抵抗裂隙扩展的能力，降低了含交叉裂隙节理岩体劈裂破坏出现的突然性。

BOLTING EFFECT AND FAILURE MODES OF JOINTED ROCK MASSES WITH CROSS-CRACKS

The bolted and unbolted jointed rock mass specimens with cross-cracks were simulated by similar materials. The angles between the primary cracks and the secondary cracks，the positions of the bolts and the angles between the bolts and the loading directions were taken as the control parameters of the specimens leading to the total of 32 groups of specimens of similar material be produced. The uniaxial compression tests of the specimens were carried out to obtain the bolting effect and the failure modes of the jointed rock masses with cross-cracks. The test results showed that：(1) The strengths of the specimen reached the maximum values if the bolting position was above or under the crossing points of the cross-cracks for the group of specimens with the same angle between the primary and secondary cracks. When the bolting position went through the crossing points of the cross-cracks，the strengths of the specimens did not reach the maximum values but its after peak values were stable. (2) The majority peak strength values of the bolted rock masses with joints and cross-cracks are higher than those of the ones with a single crack. (3) The angles between the primary and the secondary cracks affected the mechanical properties of jointed rock masses with bolting. The jointed rock mass had the best bolting effect when the angle between the primary crack and the secondary crack was about 30°. (4) The bolt increased the ability of the jointed rock mass to resist the cross-crack propagation and reduced the possibility of jointed rock masses to a sudden failure.