| Rock mass refers to a complex geological medium formed during a long period of tectonic movement.Most natural rock masses consist of intact rocks and structural planes which include Joints,foliation,fissures,faults,etc.Existence of fissures affects the stability and permeability of rock mass,and then further leads to the reduction of engineering safety.The above phenomenon normally happens in practical engineering nowadays,represented by the construction of hydraulic and traffic tunneling,the dam foundation,etc.The existence and distribution situation of fissures make a difference to the material property of rock mass,which act as the key factor within the research of deformation and fissure characteristic under a loading condition.Shortage of analysis error and poor efficiency does exist when conducting a fissure measurement by the conventional method under a contiguous pattern.However,Non-contact measuring method,represented by digital image measurement,cannot realize the specific analysis in a rock mass with complex-distribution fissures,which can be referred as “Vectorization” in this thesis.Theoretical research on vectorization algorithm was performed for the separation of complex fissures and the extraction of morphological parameters.Integrated fissure-analysis program was then developed through the program development system-Delphi.Afterwards,experiments on rock-like specimens were carried out to verify the application effect of fissure-feature-recognition program in laboratory tests.What is more,method for PFC modelling with fissures was finally proposed compared with the digital image process technology.The main results and conclusions are as follows:(1)Based on the geometric distribution characteristics of rock fissures,basic distribution models are proposed for vectorization realization.Distribution situation of complex fissures is extracted as a combination of linger fissure,cross fissure,circumferential fissure and combination fissure.(2)A fissure-vectorization method was designed based on image features of rock fissures.Tracking-storage algorithm and priority judgment algorithm were developed based on the morphological distribution feature that the fissure skeleton varies between two endpoints.Then the function of vectorized-fissure-storage was realized based on above algorithms.A series of parameter algorithms were designed corresponding to feature extraction,in terms of fissure quantity,fissure length,average fissure width,and fissure ratio.(3)Feature recognition program was developed based on digital image process technology.Relevant function was set inside such as image preprocessing,image binarization,vectorization storage and morphological parameter output.(4)The fissure-feature recognition method is applied into the uniaxial compression experiment of rock-like samples.The function is realized which can simultaneously obtain “deformation measurement” based on DSCM and “fissure feature recognition” on the same observation surface of rock-like specimen.(5)The fissure-feature recognition method is applied into the PFC simulation.An auxiliary modeling program,corresponding to PFC joint-and-fissure samples,was developed based on the principle of image feature recognition.Two modeling schemes were then proposed based on the proposed program. |
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