摘要
在岩石相似材料试件中设置三维表面裂隙,制作不同锚固方式的试件,对其进行单轴压缩试验,研究锚杆对试件强度以及预置裂隙扩展模式的影响。试验结果表明,与无锚试件相比,4种加锚试件的抗压强度和压缩弹性模量均有不同程度的提高,而且锚杆对压缩弹性模量的增强效果比对抗压强度的增强效果更显著。4种加锚试件的残余强度大体相等,比无锚试件的残余强度提高了2.0～2.5倍。加锚试件的破坏过程大致分4个阶段:孔隙裂隙压密阶段、弹性变形至微弹性裂隙发展阶段、非稳定破坏阶段和破裂后阶段,试件表面宏观裂纹均出现在破裂后阶段。由于锚杆的加固止裂作用,预置裂隙的扩展模式发生变化,加锚试件内部出现了弧形破裂面和剪切薄弱面。试验中共出现3种裂纹:张拉裂纹、剪切裂纹和拉剪复合裂纹。
Three-dimensional surface fracture is set in specimens composed of rock similar material.In order to get the effect of bolts on strength and propagation mode of the pre-existing fracture,uniaxial compression tests are carried out on specimens with different anchorage modes.The results show that,comparing with the specimens without bolts,compressive strength and compression modulus of reinforced specimens increase in different degrees.Compression modulus of reinforced specimen is enhanced more significantly than compressive strength.Residual strengths of four types of reinforced specimens are approaching to each other with the value being about 3 to 3.5 times that of specimen without bolt.The failure process of anchored specimen is divided into four phases： ① initial fracture compression phase;② micro-fractures developing phase;③ unsteady failure phase;④ post-failure phase.And the surface macro-fractures all appear in the post-failure phase.Due to the reinforced and crack arresting effect of bolts the mode of crack propagation changes.Curved fracture plane and low-shear-strength plane are found in the reinforced specimens.Three types of cracks are found in test,namely tensile crack,shear crack and tensile-shear mixed crack.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2011年第11期3288-3294,3305,共8页
Rock and Soil Mechanics
基金
国家自然科学基金资助项目(No.50874047)
国家自然科学基金(No.40902083)
国家杰出青年科学基金(A类)资助项目(No.50625927)
关键词
单轴压缩
锚杆
三维表面裂隙
加固止裂作用
扩展模式
uniaxial compression
bolt
3D surface fracture
reinforced and crack arresting effect
propagation mode
