裂隙对白云岩抗压性能的影响研究

Study on the Effect of Cracks on Dolomite Compressive Properties

裂隙是影响岩石或岩体压、拉、剪等力学性能的重要因素之一。文章通过对含裂隙的白云岩试件进行单轴压缩试验,分析了不同裂隙优势角(0°、15°、30°、45°、60°、75°、90°)、裂隙数量密度及裂隙长度密度对白云岩抗压性能的影响。试验得出:(1)当裂隙优势角α=30°时,白云岩的屈服强度σq取得最小值25.29 MPa,当α=90°时σq取得最大值109.66 MPa,且α与σq符合先减后增的二次函数变化趋势;当α=30°时,白云岩的失效强度σs取得最小值61.65 MPa,当α=90°时σs取得最大值128.70 MPa,且α与σs符合先减后增的二次函数变化趋势;当α=30°时,白云岩的弹性模量E取得最小值32.10 GPa,当α=90°时E取得最大值75.65 GPa,且α与E符合先减后增的二次函数变化趋势。(2)随着裂隙数量密度ρs的增大,屈服强度σq呈先减后增再急剧减小的三次函数变化趋势,失效强度σs呈先增后减的二次函数变化趋势,弹性模量E呈先增后减的二次函数变化趋势。(3)随着裂隙长度密度ρc的增大,屈服强度σq与失效强度σs均呈逐渐减小的对数函数的衰减趋势变化,而弹性模量E呈先增后减再急剧增加的三次函数变化趋势。

Crack is one of the important factors influencing the mechanical properties of rock or rock mass,pull and shear. The article analyzed the influence of the different crack advantage angle(0°,15°,30°,45°,60°,75°,90°),the quantitydensity of crack and the length density of the crack on the compressive properties of dolomite by single axial compression test for the crack of dolomite specimenstest conclusion: 1) When fracture edge angle α= 30°the minimum yield strength of dolomite σq= 25.29 MPa fracture edge angle α= 90° the maximum yield strength of dolomite σq= 109.66 MPa,the α and σqare in line with the change of quadratic functionsmaller and then bigger;fracture edge angle α= 30° the minimum failure strength of dolomite σs= 61.65 MPa fracture edge angle α= 90° the maximum failure strength of dolomite σs= 128.70 MPa the α and σsare in line with the change of quadratic function;fracture edge angle α= 30° the minimum modulus of elasticity of dolomite E = 32.10 GPa fracture edge angle α= 90°the maximum modulus of elasticity of dolomite E = 75.65 GPa,the α and E are in line with the change of quadratic function. 2) With the increase of the density of the fracture amount ρs,the yield strength σqshows the change trend of the three functions which first decrease and then sharply reduceand the failure intensity σsis shows the change trend of quadratic funtion which first increase after decreasethe elastic modulus E shows the trend of quadratic function. 3)With the increase of the density of the fracture length ρc,the yield strength σqand the failure strength σswhich show the logarithmic function ofdecrease,and the elastic modulus E shows the trend of three functions.