The Research On The Rock Meso Damage Law Based On CT Technology

With the rapid development of engineering construction industry, theproblems of rock mechanics has become a hot subject for research scholars athome and abroad. But the rock mechanics is a developing subject, and theresearch is very complex, so there are still a large number of difficult problemsin rock for engineering engineering and technical personnel to solve. And theunderstanding of the mechanical properties of rock, will eventually bereflected in how to describe the stress-strain relationship.This paper is based on the analysis on CT image, to obtain some basicproperties of sandstone. With damage mechanics, the constitutive model ofsandstone specimens were studied.This paper introduces the mainly used instrument in test: High precisionmicro CT system and micro three axis compression instrument, small drillingand milling machine. Do three axial compression test on three kinds ofsandstone specimens, observation and analysis the test results of rock failure under different confining pressures on the macro. Combined with the highprecision micro CT instrument, monitoring damage of rock specimen underuniaxial compression, obtain a large number of micro CT image,use a softwareprocessing the CT images, observation and analysis the rock specimenonfailure process on the microscopic. Based on the CT numbers in CT image, thestrength of the rock is analyzed, the inhomogeneity of the initial rock densityand the damage of the specimen during the process of compression damage areexplained.Introduced the concept of micro unit, Through the statisticaldistribution of CT numbers, determine micro unit strength of rock obeyWeibull distribution.Comparison of micro unit strength distribution in thedifferent compressive failure of rock specimen, after the specimen wasdestroyed the micro unit strength distribution curve will move to theleft.Introduce the concept of damage variable, according to the change ofdamage variable in the process of compression,study the damage evolution ofsiltstone specimen. Combined with the method of statistical damage, dividedthe rock compression process into three stages, and establish the theconstitutive model of each stage. The constitutive model of the siltstonespecimen under different confining pressures is established,and the model isverified...