Abstract:
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.