工程中广泛存在的复合层状围岩的软弱层几何特征(倾角和厚度)对岩体稳定性的影响至关重要。为研究软弱层厚度及倾角对复合层状岩体的力学行为影响, 首先, 开展了含不同软弱层倾角(0°、30°、45°、60°)和厚度(1、2、3、4 cm)的复合层状岩体试样的单轴压缩试验, 试验结果表明, 随着软弱层倾角增加, 试样的峰值强度和弹性应变能密度逐渐下降, 但下降幅度随厚度的增加而降低, 同时试样破坏模式由非层理面内张拉或整体破坏转为层理内滑移破坏; 随着软弱层厚度的增加, 试样的峰值强度逐渐减小, 试样的破坏模式由沿层理面滑移转为层理面滑移与轴向劈裂的组合破坏模式。其次, 通过最大信息系数分析表明, 软弱层的厚度和倾角分别为试样力学特性与能量特性的主控制因素。最后, 基于能量理论分析并结合峰前弹性应变能比和耗散能比, 发现软弱层的不同倾角和厚度导致能量释放模式不同, 进而影响试样的破坏模式和强度特征。研究结果揭示了软弱层对复合层状围岩的重要影响规律, 对类似岩体的稳定性分析具有实际的参考价值。

Composite laminated rocks are widely existed in rock engineering, where the geometric characteristics (inclination angle and thickness) of the weak layers have a crucial impact on the stability of the rock mass. To study the influence of the thickness and inclination angle of the weak layer on the mechanical behavior of composite laminated rocks, uniaxial compression tests were carried out on composite laminated samples containing weak layers with different inclination angles (0°, 30°, 45°, 60°) and thicknesses (1, 2, 3, 4 cm). The results show that the peak strength and elastic strain energy density of the samples gradually decrease as the inclination angle of the weak layer increases. However, the rate of decrease diminishes with the increase of layer thickness, while the failure mode gradually transitions from overall failure within the non-layered plane to shear failure along the layered plane. As the thickness of weak layer increases, the peak strength of samples gradually decreases, while the failure mode transitions from slip along the layered plane to a combination of axial splitting failure and slip along the layered plane. Furthermore, the maximum information coefficient analysis shows that the thickness and inclination angle of weak layer are the main controlling factors for the mechanical properties and energy characteristics of the samples, respectively. Additionally, based on energy theory analysis and combined with the elastic strain energy ratio before the peak strength, it was found that different inclination angles and thicknesses of the weak layer led to distinct energy release patterns, which in turn affect the failure modes and strength characteristics of samples. The results above reveal the significant influence of weak layers in composite laminated surrounding rock, demonstrating practical application value for the stability analysis and design of rock masses.