Study On Outcrops Joint Characteristics And Rock Mass Quality Of Aqi Section In Xinjiang Pre-selection Area For The Disposal Of High Level Radioactive Waste

All kinds properties of the developed fractures and joints in rock mass are important basis for the analysis of the mechanical properties, hydraulic properties, as well as engineering stability of rock mass. It is quite necessary to research the fracture and joint for they have an important influence on the construction and operation of the underground mining, tunnel, rock slope and high level radioactive wastes(HLW) disposal. The rock mass joints are characterized with extensive distribution, large quantities, a certain regularity in statistics, and its distribution characteristics can be obtained by researching the characteristics of joints of limited outcrop or by artificial excavation surface. In situ stress is one main factor of the geological environment, the regional stability evaluation, and the construction of underground projects. It is a significant important subject for HLW that combines the ground stress level, rock mass quality, and the structure characteristics of rock mass. This paper researched the characteristics of the joints, in situ stress state, characteristics of rock core cracks and rock mass quality based on the investigation of the rock surface joint and mapping rock core cracks by engineering background of Xinjiang Aqi Mountain section of Chinese geological disposal of HLW.14 dominant groups of joint orientation were obtained by the rose diagram method and stereographic projection method. And joint occurrence probability density had been fitted and tested that it obeyed normal distribution. Negative exponential distribution could be well fitted the joint spacing and lognormal distribution could be well fitted joint trace length. Outcrop trace midpoint density and mean trace length in every region were obtained based on circular sample window method. Drilling core fracture characteristics were analyzed and counted. And in situ stress distribution was analyzed based on the K value method and I value method that provided the basis for analyzing rock mass quality.The qualitative and quantitative description of the characteristic of ground surface joints will provide a basis for the site selection and construction of high level radioactive wastes disposal. On this basis, the evaluation method of JSR has been utilized to evaluate the rock mass quality of Aqi Mountain and the evaluation results showed that rock joints in Aqi Mountain Areas were very slight, and the rock mass integrity was very good. Simultaneously,it also confirmed that the JSR method could well characterize the developed degree of joints in rock mass, and it is reasonable and feasibility to employ this method to preliminary evaluate the quality of the rock mass engineering.