Experimental Study Of High Stress And Meso Rock Creep

The stability evaluation of rock mass has been considered as an important subject in the field of rock and soil mechanics, and it’s the foundation to ensure the safety of geotechnical engineering construction and operation. Rock creep has been one of the different important factors which effect the stability of rock mass. This paper is based on the national natural science fund project "under the condition of high stress rock creep fracture criterion research"(project number:51004007) and Jiangxi province natural science foundation of "the rock creep rupture microscopic mechanics effect quantitative research "(item number:20114bab216026). The hard diorite which was found in a copper ore in Anhui has been the research object. Rock creep properties, internal cracks form and key parameters extraction method, etc have been studied in the high stress condition. The following results have been obtained:(1) The RLJW-2000microcomputer is used to control rock triaxial shear rheological texter The rock samples’triaxial creep tests are done by the loading way of the classification incremental cyclic loading and unloading and the experimental data are collected and analyzed. After the analysis of creep process in every stages. Obtained confining pressure case of the same, before the breaking stress is not reached, the creep of the rock sample with increasing stress is increased, and gradually becomes a certain value, the strain rate is also gradually reduced; achieve stable creep used time is proportional to the partial stress; strain and axial load is approximately proportional to the instantaneous axial loads at all levels and growth, and the instantaneous strain more than about98%of the total strain.(2) Analysis on the experimental creep data and deformation law is used to determine whether the creep law conforms to the Burgers creep model. Using this model as foundation, and with the Quasi-Newton method (BFGS) selected to identify the corresponding parameters in the model, the parameters of creep model will be got successfully without the choosing initial parameters.(3) Through the ACTIS300-320/225CT/DR high resolution industrial CT real-time imaging system, the generation and expanding process of crack are recorded by image in the process of creep. As the quantitative extraction of crack has always been the hotspot problems of rock fracture, the mathematical software Matlab is chosen as an analysis tool to present the crack with dimensional space form and the crack volume is calculated.Reference is provided for rock creep study under high stress condition by this researched result as well as a method for rock mass engineering is provided. The theoretical foundations for various rock mass engineering design, instability prediction and stability analysis are also provided. The research for further research the rock creep rupture made some work. It has some certainly application prospects in the field of rock mass engineering such as mining engineering, underground construction engineering, national defense engineering, etc.