基于CT试验的岩体分区破损本构模型

在砂岩单轴压缩CT试验的基础上,定义了岩土材料的安全区、损伤进行区和破损区,对分区的CT阈值标准进行了讨论和经验选定。在此标准下,取得了所有断面在各加载阶段下的分区结果,并以第5扫描断面为例给出了分区的结果。利用数学形态学的图像测量技术对所有断面各区的CT信息进行了检出和统计分析,并对各个区上砂岩CT数随加载过程的变化规律以及破损区产生的条件进行了研究。根据检出的各加载阶段的安全区、损伤进行区和破损区的CT数统计资料,定义了一个基于CT数的统计损伤变量,建立了损伤演化方程,以此为基础建立了可反映砂岩分区破损的本构模型。

SUBAREA BREAKAGE CONSTITUTIVE MODEL OF ROCK MASS BASED ON CT TEST

Based on CT test of a certain sandstone under uniaxial compression,the safety zone,the damaging zone and the fracture zone of the sandstone are defined. Then,the divisional criteria by CT number which is used to acquire the binary images of the divisional zones from the CT images at each loading stage are discussed and determined through experiment. On the basis of the divisional criteria,the above three zones of each scanning section at each loading stage are obtained. Furthermore,taking the 5th scanning section for example,its divisional results at each loading stage are given. Then,utilizing the image to measure the technique of mathematical morphology is adopted to analyze the CT number information on these zones in each scanning section individually,which is picked over and calculated through image disposal technology. Moreover,the changing law of CT number on these zones of sandstone changing with the loading process and the procreant conditions of the damaging zone and the fracture zone are presented. Finally,according to the statistical results of CT number on these three kinds of zone obtained at each loading stage,a statistical damage variable based on CT number is defined;and the equation of damage evolution pertinent to this variable is established too. Based on all these data,a constitutive model which can reflect the divisional damage-fracture of sandstone is constructed.