| Rock mass is a discontinuous geological body with structural planes of varied mechanical properties and spatial conditions. Numerous examples of rock mass engineering indicate that the deformation and breaking law of rock mass depends on its structural characteristics and the stability of rock mass construction is controlled by the very structure of rock mass. Therefore, in order to ensure the structural stability of rock mass construction and production safety, researches must be conducted into the natural characteristics and mechanical properties of structural plane and followed by adequate measures for controlling the deformation and breaking of rock mass structural plane.This paper takes rock mass structural plane that influences the stability of rock mass construction as the main subject of investigation and the underground mining in Chengchao Iron Mine as an illustrating example. For a systematic study of the mechanical features of rock mass structural plane and of measures to control the rock mass structural plane, the methods of theoretical analysis, field survey, computer simulation, numerical calculation and engineering practice are employed jointly, aided by the integration of macro-study with micro-study, qualitative approach with quantitative one and theory with practice. The principle of combining rock mechanical theories with engineering practice is followed from beginning to end, which makes it possible to apply theoretical results to engineering practice, perfect the research method in raising the structural stability of underground construction and solve problems with production in enterprises. With this end in view, the following research has been done:1. Starting directly from nonlinear complex systems, the study has analyzed the self-similarity of part and the whole body of irregular shape by applying the fractal theory. The fractal features of spatial distribution of rock mass structural plane are researched. It proposes the use of fractal dimension for reflecting the dominance and scope of structural plane in spatial distribution. In the meantime, a comprehensive field investigation into the structural planes of rock masses in Chengchao Iron Mine is conducted, which, together with the application of statistic probability model and the analysis of investigation results of joint fissures, has determined the distribution function of structural plane parameters. On this basis, visual programming technique is used and an interactive structural plane network simulation system FRMOD with all functions is worked out, which is simple and convenient to operate. The joint fissure distribution in ore masses at -302m in Chengchao Iron Mine is simulated with computer and the network graph of the joint fissure distribution arrived at. This opens up a new way of solving fractal dimension with the box method based on the computer simulation graph of structural plane. The fractal dimension of structural plane of rockinmass in Chengchao Iron Ore is obtained, which presents a true picture of the fractal features of rock mass structural plane.2. By introducing damage tensor and net stress, this study has analyzed the mechanical properties of rock mass structural plane, hi this way, the rock mass question is macroscopically transformed into one of continuous medium mechanics, hi the light of the engineering reality in Chengchao Iron Mine, the damage tensor of the area under research has been obtained on the basis of engineering geological survey. The elastoplasticity finite element calculation program DFEM is successfully developed, which is based on damage mechanics model. The comparison and analysis of calculations with damage elastoplasticity and with conventional finite element model show that the damage model that calculates with rock mechanical parameters are more precise than conventional finite element model in reflecting the anisotropy and discontinuity of rock masses.3. On the basis of the ore mass conditions and the production reality in Chengchao Iron Mine and in the light of...
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