Papers by Author: Li Jun Han

Abstract: In order to study the grouting reinforcement effect of structural plane in cracked rock mass under uniaxial compression test and reveal the essence and mechanisms of grouting reinforcement, the roughness of structural plane in cracked rock mass was measured and studied. The influence of grouting on strength, JRC and stiffness was analyzed through shear tests of structural plane of cracked rock samples around grouting reinforcement. Test results were back-analyzed using JRC－JCS mode. The results showed that the JRC of structural plane in artificial cracked rock of the same rock mass was similar and replicable, the JRC value was about 8-10. Stiffness, roughness, peak shear strength (PSS), residual strength (RS), shear strength parameters (SSP) and slope of upward section (SUS) of structural plane were significantly improved by grouting reinforcement. The theoretical formula of structural plane stiffness was given by theoretical analysis.

Abstract: A complete stress-strain experiment curve, gained through exerting low confining pressure on brittle rock, reflects the deformation and destruction process of rock under different confining pressure, and reveals that after the destruction of rock, not only slip deformation but also re-destruction process will take place, which would possibly lead to further reduction of the mechanical properties of the rock mass. Through the analysis of the relation between complex failure modes, load carrying capacity after rock destruction and the volumetric strain, the paper gives us a further explanation of the complex destructive process of rock. The basis for the rock’s load-carrying capacity after destruction is an effective restraint stress, which shows that effective supporting in underground engineering is the key factor for providing the cracked surrounding rock with load-carrying capacity and guaranteeing the stability of the structure.

Abstract: Surrounding rocks of deep underground engineering are generally cracked, between which and support exists combined effect that can be reflected by the mechanical characteristics of cracked rock mass under lateral Constraints. In this paper, the strength and deformation characteristics of the cracked rock mass under lateral Constraints are investigated with methods of physical and numerical experiments. The results show that the rock mass behaves as equivalent continuum and tends to stable after deforming and re-fracturing, and has stress hardening behavior. These characteristics are obviously different from that of shearing slippage of rock samples at the residual stage of triaxial experiment.