Numerical Simulation Of Crack Propagation Between Two Adjacent Blast Holes

Because of the complexity of the progress of rock blasting,till now,the mechanism of crack propagation between two adjacent blast holes,which still be a good topic to be studied.In scientific research,the commonly used methods are theoretical analysis and experimental research.However,there are still many deficiencies in the research of this subject:Complete theoretical analysis is only applicable to some simple and idealized problems.For complex problems,improper simplified analysis can easily lead to erroneous conclusions;In the experimental study,due to the transient nature of the explosion process,the complexity of the medium and the limitations of the test technology,the researchers could not obtain sufficient spatial time data,such as the full time range data of the rock stress and strain that the researchers were most concerned about.Numerical simulation has sufficient advantages in the above problems,and it can make a more comprehensive and intuitive observation on the dynamic forming process of cracks between two blast holes.It should be pointed out that,in the process of the numerical simulation research,many factors will affect the results,different simulation design sometimes also can produce large difference of calculated results,This is why many researchers can't fully agree with the method of numerical simulation.With the rapid development of computer technology,numerical simulation has become one of the main research means for scientific research,in order to conclude the results of research value,must systematically study the issues involved in the process of simulation research,and it is still of great significance for the study of the problem of double-blast holes.In this paper,the traditional blasting theory is studied,through theoretical analysis and simulation verification,the defects of the traditional stress wave mechanism are discussed in combination with the fact that the crack between holes are first formed in the hole wall;Three commonly used rock constitutive models are selected to compare the dynamic responses;Ls-dyna was used to establish a double hole model with hole spacing of 10 diameters.Analysis of the stress-time curve of the rock unit in the connection of the blast holes and the vertical line in the line,obtain the stress peak distribution trend of maximum principal stress,maximum shear stress,etc.7 orthogonal experiments of tensile failure,compression failure and shear failure were designed to analyze the fracture morphology of each group,which are accorded to get the failure type of rock between two blast holes;Study found that the stress waves generated by the two holes did not meet when the cracks were initially formed at hole wall.After the two pore stress waves met each other the cracks run through.