堆積軟岩における水平試錐孔壁崩壊現象の発生メカニズムに関する研究

• Material Type: 文書・図像類
• Title: 堆積軟岩における水平試錐孔壁崩壊現象の発生メカニズムに関する研究
• Author/Editor: 東海大学
• Author Heading: 東海大学
• Publication Date: 2004-02
• Publication Date (W3CDTF): 2004-02
• Alternative Title: A research into the failure mechanism around horizontal boreholes excavated in sedimentary rocks
• Periodical title: JNC TJ7400 2005-021
• Text Language Code: jpn
• Target Audience: 一般
• Note (General): 研究の対象とした堆積軟岩に展開されている東濃鉱山は、日本で最大のウラン鉱床である月吉鉱床に位置している。東濃鉱山にある北延NATM坑道周辺の堆積軟岩に掘削した裸孔の水平試錐孔において、大深度における硬岩での坑道掘削においてしばしば発生する「肌落ち」や「山はね」に似たような孔壁が崩壊する現象が観察された。本研究では、大深度で想定される堆積軟岩の孔壁崩壊現象のメカニズムを解明することを目的とし、以下の項目について研究実績し取りまとめた。(1)孔周辺岩盤の物性試験、(2)岩盤パラメータの変化計測、(3)数値解析; Tono mine is one of the uranium mines of Japan and it has been the subject of extensive research regarding the nuclear waste disposal in rock. The top formation of the mine consists of sedimentary rocks ranging from sandstone to siltstone. An exploration adit was excavated by using the NATM, and this adit therefore was named as the NATM adit. At an extension of this adit, a series of horizontal boreholes were excavated for measuring in-situ stresses. The failure was observed in these boreholes, particularly at their crown and sidewalls. Following these observations some new boreholes were drilled into sedimentary rocks to investigate the causes and mechanism of failure of these non-supported boreholes. It is experimentally known that the rock exhibits some anomalous behaviour before the ultimate rupture, such as seismic electric signals, high acoustic emission activity. Furthermore, the behaviour of sedimentary rocks greatly depends upon their water content and some swelling, shrinkage, slaking may occur depending upon the environmental conditions. To investigate the coupled behaviour of sedimentary rocks in relation to clarifying the in-situ observations in the adit a research program was initiated, which consists of (1)Experiments (2)In-situ multi-parameter monitoring, and (3)Numerical studies. Experiments were concerned with, physical, electrical and mechanical properties of sedimentary rocks and their water-content migration characteristics. In-situ multi-parameter real-time monitoring involved electrical potential variations, acoustic emission activity, deformation, temperature and humidity variations in the boreholes and in the adit, which may be indicators for the possible failure around the boreholes. Numerical-studies were concerned with the conventional elasto-plastic stability analysis and also coupled analyses of water-content migration and stress field. The experimental studies clearly indicated that rocks around the boreholes exhibit time dependent ...
• Source: /JNC-TJ7400-2005-021.pdf （fulltext）; https://jopss.jaea.go.jp/pdfdata/JNC-TJ7400-2005-021.pdf
• Access Restrictions: 限定公開
• Data Provider (Database): 国立情報学研究所 : 学術機関リポジトリデータベース（IRDB）（機関リポジトリ）; https://irdb.nii.ac.jp
• Original Data Provider (Database): 日本原子力研究開発機構 : JOPSS:JAEA Originated Papers Searching System

• Summary, etc.: 研究の対象とした堆積軟岩に展開されている東濃鉱山は、日本で最大のウラン鉱床である月吉鉱床に位置している。東濃鉱山にある北延NATM坑道周辺の堆積軟岩に掘削した裸孔の水平試錐孔において、大深度における硬岩での坑道掘削においてしばしば発生する「肌落ち」や「山はね」に似たような孔壁が崩壊する現象が観察され...