壁面强度及粗糙度对含软弱夹层岩体影响研究

Experimental Study on the Effect of Wall Strength and Roughness on the Mechanical Properties of Rock Mass with Weak Interlayer

软弱夹层作为一种特殊的结构面是影响岩体稳定性的重要因素之一.软弱岩层与围岩接触壁面的物理力学性质很大程度上影响着整个岩体的强度特征和破坏特征.为研究其中规律自行设计并制作了不同粗糙度和强度壁面的试样,通过室内直剪试验结果分析了壁面强度和壁面粗糙度对岩体强度特征和破坏特征的影响.发现岩体峰值抗剪强度与壁面强度和粗糙度成正相关关系,法向应力较小时,随着壁面强度增加,试样主破坏裂纹与水平面夹角越来越小,随着壁面粗糙度增加,岩体从无裂纹变成夹层上部岩体出现裂纹,法向应力较大时,随着壁面强度增加,试样主破坏裂纹与水平面夹角越来越大,随着壁面粗糙度增大,主裂纹与水平面夹角逐渐减小,并且裂纹数有所增加.

As a special structural plane,weak interlayer is one of the important factors affecting the stability of rock mass. The physical and mechanical properties of the contact wall between the weak rock layer and the surrounding rock largely affect the strength and failure characteristics of the entire rock mass. In order to study the law,the wall samples with different roughness and strengths were designed and produced,and the influence of wall strength and wall roughness on the strength and failure characteristics of rock mass was analyzed through indoor direct shear test.It is found that the peak shear strength of the rock mass is positively correlated with the wall strength and wall roughness. When the normal stress is small,with the increase of the wall strength,the angle between the main failure crack and the horizontal plane of the sample becomes smaller and smaller. As the wall roughness increases,the rock mass changes from no cracks to cracks in the upper rock mass of the interlayer. When the normal stress is large,the angle between the main failure crack and the horizontal plane of the sample becomes larger and larger with the increase of the wall strength. As the wall roughness increases,the angle between the crack and the horizontal plane of the sample gradually decreases,and the number of cracks increases.