含充填物的厚壁圆筒砂岩的力学性质研究

基于单轴和常规三轴压缩试验,采用完整试样、空心及铝棒充填的厚壁圆筒试样,模拟研究支护对圆形巷道的强度、变形和破坏特征的影响。结果表明:充填试样和完整试样的单轴压缩强度和弹性模量大致相同,而厚壁圆筒试样的强度和弹性模量则偏低31.8%和22.4%;厚壁圆筒试样三轴压缩时出现沿圆周层状破坏,其剪切面积随着围压的增大而减少,围压40 MPa时出现明显塌孔;充填试样进入塑性屈服阶段后,充填物才会对试样的力学性质产生明显影响;充填物改变了孔道内部应力状态,使孔道内壁由原来的二维应力状态恢复到三维应力状态,抑制了孔道内壁的侧向变形,防止自由面岩石的脱落;岩石破坏并不代表承载能力消失,充填试样岩石破坏后失去黏结力,载荷主要通过充填物与岩石、岩石裂隙之间摩擦力共同承载。

Mechanical property of thick-walled hollow cylinders of sandstone with filling

Based on uniaxial and pseudo-triaxial compression tests, the effect of support on the strength, deformation and failure characteristics of circular roadway is simulated by using solid specimens, thick-walled hollow cylinder specimens and thick wall cylinder specimens with aluminum rod. The tests indicate that: (1) The uniaxial compressive strength and elastic modulus of solid specimens and filled specimens are roughly the same, and those of the cylinder specimens are decreased by 31.8% and 22.4%; (2) When the thick-wall cylinder specimens have layered destruction along the circumference under triaxial compression, the shear area decreases with the increase of confining pressure, and collapse hole appears when the confining pressure is 40 MPa; (3) Filling have significant influence on mechanical properties of specimens when the filled specimens enter the plastic deformation, and it can change the rock stress state and make the two-dimensional stress state of inner wall back to the three-dimensional stress state; (4) Filling can cause inhibition of larger lateral displacement of inner wall and prevent the rock of free surface fall off; (5) Rock failure doesn't mean that the bearing capacity disappears, rock of filled specimens loses cohesive force, and the bearing capacity of filled specimens mainly depends on friction forces of filling and rock and rock fractures.