Abstract:

In the system of uniaxial loading with servo control, the experiment of uniaxial loading on the samples of prefabricated cement mortar with multiple fissures was made, aiming to explore the influencing rules of strength of fracture failure which belong to the rock-like material with different angles and densities of distribution of the fissures. Basing on the arrangement and analysis of the experimental data, a strain-softening model is established by using the software-FLAC3D; and then the numerical analysis of the strain-softening model carried out. The experimental data and the results of numerical calculation show that: When the density distributions of fissures are the same, the angle of the fissures plays an obvious part in the strength of fracture failure of the samples. And when the angle of the fissures is about 25°, it has the minimum value of strength. When the angles of the fissures are the same, the strength of fracture failure of the samples has a relationship with the density distribution of fissures. When the angle has a small value, the effects of density distribution of fissures are obvious. And with the increasing of the inclination angle of the fissures, the effects are increasingly weak. This conclusion provides a basis for predicting the changing rules of strength of the wall rock with multi-fissures in the underground projects.

Key words: rock-like material with multi-fissures, uniaxial compression, strength of fracture failure, double influencing factors, numerical analysis