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选用改性橡胶粉-水泥砂浆来模拟真实岩石,用玻璃纤维增强塑料作为锚杆材料,研究锚杆对三维表面裂隙岩体的加固止裂效果。结果表明,锚杆提高了裂隙岩体的变形模量和单轴抗拉强度,变形模量随锚固角的增大而增大,而单轴拉伸随锚固角的增大先增大后减小,当锚固角β=45°时,锚杆对单轴抗拉强度的提高幅度最大;锚杆通过其抗滑移和抗剪切性能使裂隙岩体避免发生脆性破坏,并且在预置裂隙起裂之后存在不同程度的残余强度;单轴拉伸条件下加锚或无锚裂隙试件的破坏均以预置裂纹尖端为突破口产生翼裂纹,其扩展方向大致与轴向拉应力方向垂直。当锚固角小于某个临界值时,会有次生裂纹产生;拉伸条件下,含裂隙试件的破坏机制是张拉型裂纹的贯通作用。
The modified rubber powder-cement mortar was used to simulate the real rock, and the glass fiber reinforced plastic was used as the bolt material to study the reinforcement and crack-arrest effect of the anchor on the three-dimensional surface fractured rock mass. The results show that the bolt increases the deformation modulus and the uniaxial tensile strength of the fractured rock mass, the deformation modulus increases with the increase of the anchorage angle, while the uniaxial tension first increases and then decreases with the increase of the anchorage angle When the anchoring angle is β = 45 °, the uniaxial tensile strength of the rock bolt increases by a maximum. The rock bolt can avoid the brittle failure by its anti-sliding and anti-shear properties. There are different degrees of residual strength after the initiation of cracking. Under the uniaxial tension conditions, the failure of anchored or no-anchor cracks is caused by the pre-crack tip breaking, and its spreading direction is approximately perpendicular to the direction of axial tensile stress. When the anchoring angle is less than a certain critical value, there will be secondary cracks. Under the tensile conditions, the failure mechanism of cracked specimens is the penetration effect of the tensile crack.