Study On Joint Geometric Features And Combination Form Of Granite Body At The Potential Site, Beishan, Gansu Province

Based on the progress of the investigation stage of the potential site of Chinese High Level Radioactive Waste,Beishan,Gansu Province,and combined with the fracture investigation of two new deep-drilling(BS05,BS06) at the site,in 2008,the paper carried out joint research on the geometric features of the survey:the rose diagram of joint and the graph of isodense joint poles were applied to classifying the joint orientations;the probability density analysis of joint orientations was used to Verify the normal type;the mean trace length and trace midpoint density of rock mass joints was studied by the circular window method;based on the special background, the potential site of the high level radioactive waste,the author discussed on division method and rationally elected the elements and division method of structural homogeneity of rock mass in granite.To explore the evolution mechanism of rock mass joint in granite,the investigation and research on joint combination form was firstly studied.The combination form was classified,according to its role on mechanical,chronological and auxiliary;the stress analysis procedure was programmed by the secondary development of AutoCAD package,for X-Joints which have an important role in the mechanical analysis;then,the joint evolution mechanism was studied by X-Joints stress analysis,combined with other types of combination form.The investigation and research on joint geometric features of granite body at the potential site,Beishan,Gansu province,was complement and contrast for the fracture investigation of deep-drilling(BS05,BS06),and provided data support for 3D joints network simulation.The study on combination form explained the reason of geometric features.Both of them provided support for joint feature database at the potential site.