Experimental Study on Mechanical Properties of Anchored Rock-Like Material with Weak Interlayer Under Uniaxial Compression

The weak interlayer in rock mass is an important factor affecting the stability of geotechnical engineering. In practical engineering, bolt is widely adopted to reinforce the rock mass with weak interlayer. In order to investigate the anchorage mechanical properties of rock with weak interlayer, we employed cement mortar and gypsum to simulate rock and weak interlayer and then conducted a series of uniaxial compressive experiments of anchored rock-like material. Our experimental results show that: (1) the weak interlayer significantly increases the heterogeneity and anisotropy of rock mass, resulting in many fluctuations on the stress–strain curve. Compared with the non-bolted rock, the stress–strain curve of anchored rock exhibits stronger ductility; (2) for the non-bolted rock with inclined interlayer, the uniaxial compressive strength, elastic modulus and Poisson's ratio decreases gradually with increasing interlayer inclination. (3) The influence of the dip angle of the weak interlayer on the failure modes of rock mass with weak interlayer is more notable than anchorage angle. The failure modes of anchored rock with weak interlayer can be divided into four patterns: splitting failure of weak interlayer, splitting failure of both weak interlayer and rock, composite failure of weak interlayer splitting and rock shear fracture as well as composite failure of weak interlayer splitting and rock-interlay interface shear slip.