倾斜层理岩体预应力锚索主动锚固机理试验研究

Experimental Study on Active Anchorage Mechanism of Prestressed Anchor Cable in Inclined Bedding Rock Mass

倾斜层理顶板巷道通常具有明显非对称破坏特性,其稳定性控制是巷道支护的复杂难题,对层理岩体锚固机理研究有利于合理确定支护参数。采用相似模拟试验对不同锚固角及预应力条件下层理岩体锚固控制机理进行了研究。结果表明:锚索预应力可有效抑制层理岩体裂隙扩展,且随锚索轴向约束载荷增大抑制效果愈加明显,锚固体峰值强度较无锚时提高96.97%,锚索高阻特性使层理岩体锚固结构强度保持缓增趋势,岩体碎胀变形得到有效控制,残余强度提高148.33%;锚固角对岩体加固效果影响明显,锚固角为90°时较无锚试件其弹性模量、峰值强度及残余强度分别提高59.33%、34.34%和96.67%,锚固角为45°时较锚固角为90°时各参数分别提高16.71%、14.29%和18.64%;锚索预应力与层理岩体的承载能力正相关,预应力由0.5 kN增至0.7 kN时,试件弹性模量、峰值强度及残余强度分别提高66.14%、46.62%、26.27%,即增加锚索预应力可有效提高试件整体锚固强度;试件垂向位移量一定时,随锚固角优化及预应力提高,锚索对岩体扩容约束作用增强。

Inclined bedding roof roadway usually has obvious asymmetric failure characteristics,and its stability control is a complex problem of roadway support.The research on the anchorage mechanism of bedding rock mass is conducive to reasonably determine the support parameters.The anchorage control mechanism of bedding rock mass under different anchorage angles and prestress conditions was studied by similar simulation test.The results show that the prestress of the anchor cable can effectively inhibit the crack propagation of the bedding rock mass,and the inhibition effect becomes more obvious with the increase of the axial restraint load of the anchor cable.The peak strength of the anchor body is 96.97%higher than that without anchor.The high resistance of the anchor cable keeps the strength of the anchorage structure of the bedding rock mass increasing slowly,the swelling deformation of the rock mass can be effectively controlled,and the residual strength is increased by 148.33%.The anchorage angle has an obvious influence on the reinforcement effect of rock mass.The elastic modulus,peak strength and residual strength are increased by 59.33%,34.34%and 96.67%respectively compared with the specimens without anchor when the anchorage angle is 90°,but are increased by 16.71%,14.29%and 18.64%respectively when the anchorage angle is 45°compared with the specimens with anchor angle of 90°.The prestress of anchor cable is positively correlated with the bearing capacity of bedding rock mass.When the prestress increases from 0.5 kN to 0.7 kN,the elastic modulus,peak strength and residual strength of the specimen increase by 66.14%,46.62%and 26.27%respectively,that is,increasing the prestress of anchor cable can effectively improve the overall anchorage strength of the specimen.When the vertical displacement of the specimen is constant,with the optimization of the anchoragre angle and the increase of the prestress,the restraint effect of the anchor cable on the expansion of the rock mass is enhanced.