| Because of the heterogeneity,discontinuity and anisotropy of stratified rock mass,its mechanical properties are not only influenced by the mechanical properties of the structural planes among layers,but the mechanical properties of each layer and the gap between cracks are also crucial to the stability and safety of the rock mass engineering.In this paper,the limestone and interface materials,such as cement and fly ash,have been used to make the fracture model of the spacing of layered rock.Through the three point bending test and the numerical simulation of the particle flow,the structural effects of the fracture evolution of the layered rock are studied and analyzed.The main research work is as follows:?1?A layered rock mass composed of six different S/T ratios and three different mechanical properties was made.The three point bending test was carried out.The crack propagation process,the load-displacement curves and the acoustic emission?AE?data of the specimen were recorded.The bending failure modes,mechanical properties and the mechanical properties of the specimens were analyzed at three points.Acoustic emission characteristics;?2?Based on the laboratory test,using the particle flow simulation program-PFC2D,the layered simulation model is established by giving different parameters and adding the weak interface in different regions.The fine parameters of the rock materials such as R,I1 and I2 are calibrated,and a group of PFC2DD meso which can reflect the macroscopic mechanical properties of the actual indoor test is finally obtained.The results of laboratory test for layered rock samples are compared with failure modes and mechanical properties curves respectively;?3?The structural effects of the critical ratio Scr/T on the fracture evolution are further analyzed on the basis of the test,and the structural effects of the difference of the dip angle of the interface and the rock strength of the middle layer on the fracture evolution are studied systematically. |
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