Abstract Korea Radioactive Waste Agency (KORAD) established in 2009 has started a new project to collect information on long-term stability and deep geological environment in the Korean Peninsula. The data has been built up in the KORAD integrated natural barrier database system (KOINS). KOINS also includes socially and economically important information, such as land use, mining area, natural conservation area, population density, and industrial complex, because the information is used as exclusionary criteria at the site selection process of geological repository. It is believed that the KOINS will be effectively utilized to narrow down the number of sites where future investigation is required in the siting process of geological repository. 1. Introduction Geological disposal has been recognized world-widely as one of the safest methods in the light of isolating the spent nuclear fuel permanently from human and environment. Accordingly, it is required not only to understand the geological phenomena of geotectonic movements but also to perform its long-term prediction at least more than 100 thousand years for the purpose of the deep disposal. 2. Overseas research of geological disposal 2.1 Siting factors and criteria The many studies for a high-level radioactive waste geological repository reported the fundamental requirements with an emphasis on the long term safety aspects (Gordon, 2002). According to these studies, siting factors can be divided four main categories: safety, technology, land and environment, and Societal aspects. The safety aspect means siting factors of importance for the long-term safety of the deep repository (SKB, 1993). The technology aspect is siting factors of importance for the construction, performance and safe operation. The land and environmental aspect indicates siting factors of importance for land use and general environmental impact. Lastly, the societal aspects are siting factors connected to political considerations and community impact. There are fundamental requirements that must be met by a deep repository.

Abstract Frost weathering frequently occurs at high-latitude and alpine regions, as well as in winter season at mid-altitude region. The weathering damages to building stones, surface of structures and cultural heritages, and can form distinguishing geomorphology. In this research, microstructure of rock specimen is analyzed using micro X-ray CT and SEM. Using scanning electron microscope (SEM) images, particle detachment, pore connection and crack propagation/expansion were detected, and porosity is analyzed quantitatively. Using X-ray computed tomography, variation on open/closed porosity, pore size distribution, equivalent diameter and local thickness were analyzed. This research can be applied to construction, resources exploitation, prevention of geological disaster, and preservation of historical monuments in cold regions. 1. Introduction Frost weathering frequently occurs at high-latitude and alpine regions, as well as in winter season at mid-altitude region. The weathering damages to building stones, surface of structures and cultural heritages, and can form distinguishing geomorphology. Although there have been many researches to investigate frost weathering, most researchers have focused on variation on physical properties or on the rock surface. The purpose of this study is to evaluate frost weathering of igneous rocks quantitatively using micro-CT and SEM. 2. Methodology 2.1 Sample description Three types of igneous rock were collected in Korea. Basalt, sampled at Cherwon-gun, Gangwon-do, has vesicular texture with needle-shape plagioclase; Diorite, sampled at Goheung-gun, Jeollanam-do, was coarse-grained rock consisting of plagioclase, olivine, micas, quartz and microcline; and Lapilli tuff, sampled at Hwasun-gun, Jeollanam-do, was fine-grained rock with feldspar, quartz, micas, quartzite fragments, and basaltic fragments.

Abstract The purpose of this study is to visualize cracks that occur within the concrete which expands due to permeating water. This fracture may be induced when large content of sulfate of cement and high temperature surrounding environment is encountered. Although concrete is not immediately affected after heating under dry condition, it will be deteriorated when exposed water and humid conditions. The concrete expands and fractures under that conditions. This phenomenon was investigated on precast concretes. However, the mechanism of this phenomenon within the concrete is not made clear until now. Therefore, the X-ray CT method was used for visualizing change in internal structure during expansion fracture. The mechanism of the phenomenon was then clarified. Concrete cylinders with a diameter of 50mm and length of 100mm were prepared as specimens. In the laboratory, the expansion occurred and converged almost in one week's time. The X-ray CT images of specimens were taken at several expansion stages of the specimen. Using the obtained CT images, cracks were visualized on two types of scales, the whole specimen and 1 cm cube. To visualize micro size cracks, the 3DMA (3 Dimensional Medial axis Analysis) was applied to the 3D CT image to analyze the state of fracture initiation and propagation. As a result, it was clear that fractures initiate near specimen surface and progress to its core and the cracks occurred within mortar and boundary between mortar and aggregate. 1. Introduction When concrete is exposed to high temperatures such as fire, it is damaged due to thermal stress. On the other hand, even if concrete is not affected by thermal stress at low temperature, it may deteriorate due to the supply of water after heating. In general, when the concrete is heated above 70°C, the internal ettringite decompose and sodium sulfate is released. After being exposed to water, water reacts with calcium silicate hydrate or calcium hydroxide to produce gypsum. Furthermore, due to the reaction of gypsum and aluminate more ettringite is produced, hence the concrete expands and deteriorates. It cannot be said that the change of the internal structure of concrete when the concrete deteriorates is sufficiently made clear. In this study, the change of the internal structure of concrete specimen was visualized by using the X-ray CT which is one of the non-destructive inspection methods. The crack propagation behavior during expansion process, such as above phenomenon, was made clear by using the parameter indicating the amount of void inside the concrete.

Abstract Underground coal gasification (UCG) is a process of producing combustible gases by the in-situ conversion of coal into gaseous products. Coal resources abandoned under the ground for either technical or economic reasons can be recovered with economically and less environmental impacts by UCG; therefore, this technology is regarded as a clean coal technology. UCG has several advantages of low investments, high efficiency, and high benefits compared to conventional coal gasification. However, some environmental risks such as gas leakage, surface subsidence, and underground water pollution are difficult to control because the process is invisible. The reactor in UCG is unstable and expands continuously due to fracturing activity caused by coal combustion. It is, therefore, considered that acoustic emission (AE) is an effective tool to monitor the fracturing activities and visualize the inner part of coal. For this study, UCG model experiments were conducted using coal blocks of 0.55 × 0.60 × 2.74 m to discuss the applicability of AE monitoring for the estimation of the crack generations during UCG process and the extent of the gasification area. Temperatures were also monitored to understand the inner part of coal blocks because the crack generations were strongly related to thermal stress occurred by coal combustion and heat transfer. The monitoring results of AE agree with the measured data of temperatures; the source location of AE was detected around the region temperature increased. AE monitoring are expected to provide a useful data to visualize the gasifier in the underground. 1. Introduction Underground coal gasification (UCG) is a technique to extract energy from coal in the form of heat energy and combustible gases through the chemical reactions in the underground gasifier. This technique enables to utilize coal resources that remain unrecoverable in underground due to either technological or economic reasons. Gasification reaction in UCG process is promoted by enlargement of the oxidation surface around the gasification channel with crack initiation and development inside the coal seam. Fracturing activities inside the coal seam are accelerated with an increase of thermal stress caused by exothermic reactions and heat transfer, as a result, gasification reaction and cavity growth is promoted. Cavity growth influences gasification efficiency because it is directly proportional to the coal consumption. At the same time, some of environmental issues have to be cared such as gas leakage, groundwater pollution, and surface subsidence associated with the cavity growth (Bhutto et al., 2013; Imran et al., 2014; Kapusta and Stańczyk, 2011; Kapusta et al., 2013, Shu-qin et al., 2007). Therefore, techniques to evaluate the fracture activity around the gasification area have to be developed for precise control of coal gasification in-situ and minimizing environmental impacts.

ABSTRACT: Despite the significance of coral reefs as resources for development and research, only a limited amount of drilling surveys have been done on coral reefs, and obtaining comprehensive geological information remains difficultly to obtained. In the Chenhang Island survey, the digital borehole camera technology was utilized for the first time in China to provide guidance and acquire firsthand information of coral reefs, including anomalies in the rock body (e.g. fissures, cavities, traces of biological activities, interfaces, foreign strata and substances, color variations, etc), which also helped determine the causes of low or zero coring rates. In addition, data acquired by borehole camera can be used to evaluate the integrity of coral reefs. It can be concluded that: the borehole camera system is an accurate and effective tool for determining the geological characteristics of coral reefs; the system can serve important purposes in the geological survey of coral reefs. 1 INTRODUCTION The coral reefs are soil and rock structures formed from the remains of scleractinian corals, shaped by geological forces over a long period (Wei et al. 2008). Their great potential as a natural and military resource lends importance to the geological survey of coral reefs. In the drilling of Chenhang Island in Xisha (Paracel) Islands, we used deep boreholes to obtain rock cores from coral reefs and model their geological structures. The data can be used in the research of climate and environmental changes on a million-year time scale, the study of coral reefs' development and their interaction with the environment, as well as the exploitation of coral reefs for military purposes. The scientific and engineering values of such data would be significant.

ABSTRACT: Due to a variety of factors, geological disasters occurred frequently in recent years, giving people a huge loss of life, had cause for concern. Shaanxi is the southern region of geological disasters are more serious, especially landslide hazards. This study chooses Mian County, Shaanxi Province as the study area. Mian County landslide disasters are analyzed the types, distribution, development regularities and geological environmental conditions and main influencing factors of the formation conditions of landslide disaster. To use GIS, fuzzy comprehensive evaluation to evaluate the model, and the Analytic Hierarchy Process. To select engineering geological lithologic, ground motion peak acceleration, geological structure, elevation, geomorphological types, slope, annual rainfall, human engineering activities and land use type as the main evaluation factors for landslide hazard risk assessment. Landslide hazard risk is divided into a high risk, moderate risk, low risk and extreme low risk levels. 1 INTRODUCTION Mian County in Shanxi province is located in the western of Hanzhong City, north of the county is Qinling, Bashan is in the south of the county (Ruxton 1908). Mian County has complex geological conditions as a geological disaster prone city in our country. Landslide disasters caused serious losses to the local people. So how to make use of existing technical means and evaluation method to evaluate the county area, for the entire county of landslide risk assessment plays a decisive role (Fourie 1996). There is no unified method and standard of the debris flow risk assessment at home and abroad at present. Especially to evaluate the whole scope of the county is still less (Collison 1996). So it is necessary to conduct the study to improve the level of debris flow risk assessment theory (Evans 1997). It will has important theoretical significance (Tang et al. 2002). At the same time, it can also provide the basis for the entire county of debris flow prevention and management. Past research emphasis of landslide disaster countermeasures is single landslide case studies, but now the emphasis on the study of landslide hazard risk assessment is area (Collison 1996). By using AHP and Fuzzy Mathematics and Geographic Information System means the combination to achieve regional landslide hazard evaluation, it can effectively overcome the impact of human factors evaluation process.