不同结构面倾角节理岩体三轴试验力学特性

Experimental Research on Mechanical Properties of Jointed Rock Mass with Different Angles of Inclination

为了掌握贯穿型节理岩体的变形和破坏规律,对人工制备的不同倾角模拟节理岩体圆柱试样进行了系列静力三轴试验,得到了相关的应力应变曲线结果和破坏特征,进而分析了结构面倾角对节理岩体试样力学特性的重要影响.结果表明:1)随着结构面倾角的变化,节理岩体试样的应力应变曲线将不全为典型的四阶段曲线,在结构面倾角较大时结构面的变形特征十分显著,峰前曲线发生了明显转折,结构面变形占据了主导作用.2)峰值强度、残余强度和峰前线性阶段变形模量随结构面倾角增大而单调降低,而试样的脆性和剪胀性强弱、压密阶段的变形模量以及体胀、体缩量最大值等与结构面倾角的变化关系则均为非单调的.3)结构面的倾角大小影响了其与基质的相互作用规律,使得结构面或基质或者两者一起控制了节理岩体试样的变形、强度和破坏,从而形成了节理岩体试样显著不同的变形、强度和破坏特征,其变形和强度各向异性与破坏模式随结构面倾角变化而不同.

In order to master the deformation and failure mechanisms ofpersistently jointed rock mass,static triaxial tests were carried out on simulated jointed rock mass cylinder specimens,which contained structural planes with different dip angles. The related stress-strain curves and failure results were obtained. Then the influences of dip angles on the mechanical properties of jointed rock mass were studied. The results show that： 1） With the change of angles of inclination,the complete stress-strain curves are not all the typical curves including four stages,and the deformation of structural planes are significant when the angles of inclination are large, the curves have evident transitions and the deformation of the structural planes becomes dominant. 2） With the increasing of the angles ofinclination,the peak strength,residual strength and the deformation modulus in the linear stage prior to the peak value all reduce monotonously. While for the brittleness, the dilatancy, the deformation modulus in the initial compression phase,and the maximum of volume contraction and expansion,their variation is not monotonous. 3） The dip angle of the structural plane affects the laws of interactions between the structural plane and the rock matrix,which causes that the structural plane or the rock matrix or the two together control the deformation,strength and failure of jointed rock mass. The jointed rock samples exhibit significantly different characters for the deformation, strength and failure. The deformation and strength anisotropy and failure modes vary closely with the joint dip angles.