ln this paper, the real-time computerized tomography (CT) testing of the meso-damage propagation law of the whole process of sandstone failure under triaxial compression has been completed using the newest specified triaxial loading equipmentdeveloped by the authors corresponding to the CT machine. Through the CT scanning, the clear CT images were obtained includingthe microcracks compressed. growth, bifurcation. development.crack fracture, the rock sample failure and the unloading stage in thedifferent stress slates. The CT values, CT images and the other data have been analyzed, the initial damage effect factor and the c1ose effectcoefficient are introduced, and a new damage variable based on the CT values is defined. Based on the results of the CT testing of meso-damage evolution law of rock, the stress threshold value of meso-damage of rock is given, and the stress-strain Complete process curve of rack is divided into 5 sections. The initial rack damage propagation law is given in this paper.
of the meso-damage propagation law can provide Important experiment results for macro-damage theory, and it is also helpful for study of the rock failure law, In this paper. using the newest loading equipment corresponding to the CT machine, the CT real-time scanning lest of meso-damage propagation of rock under the triaxial compression has beenCompleted.The investigation of the rock failure law, aims atestablishment of the rational rock damage evolution equation and rock damage constitutive model, which will provide some Science base for rock masses strength analysis and deformationControl. It's an innovative testing method in the field of rockmechanics.
This loading equipment system includes 4 parts, There are the triaxial loading chamber, the hydraulic loading system, the data processed system and the cooling bath cyclic system, It can be use to complete the rock failure lest in the triaxial(uniaxial) compression with the international standard cylinder rock sample (50mmx 100mm),1t also can be used to complete the failure test of the soil sample (tP 61.8mmx 150mm). The configuration of the specially triaxial loading chamber for, the CT machine is: 2400101 X 1OOOmm(Fig, 1). The interior diameter of axial pressure chamber is ¢ 142mm, the maximum axial load is 400kN.
The rock sample of CT testing was the sandstone, which were sampled from the Coal Mine in Nanqiao of the Shannxi Province Pubai Mining Bureau. The CT testing was carried out in the State Key Laboratory of Frozen Soil Engineering of China, The sandstone samples were used to study the rack mesodamagepropagation law under triaxial(uniaxial) compressionwith CT real-time scanning test.For each sample there werefour cross layers from up to down, each of which was scanned.
The test results of 5/1 sandstone may be taken as an example to analyzed. Fig.2 is the CT images of each scan layer.
