掲載雑誌（和）： 岩盤力学に関するシンポジウム講演論文集 Vol： 23巻 年： 1991年 頁： 16-20頁 著者（和）： 中田　雅夫，　小瀬　幸雄，　佐々木　勝司，　福間　敏夫 タイトル（和）： 岩盤空洞周辺の緩み領域の調査について 抄録（和）：
- キーワード（和）： - 掲載雑誌（英）： PROCEEDINGS OF THE SYMPOSIUM ON ROCK MECHANICS 著者（英）： Masao NAKATA, Yukio KOSE, Katsuji SASAKI, Tosio FUKUMA タイトル（英）： EXAMINATION OF LOOSE ZONE IN ROCK AROUND UNDERGROUND OPENINGS 抄録（英）：
For estimation purpose of loose zone in rock around underground openings, in-situ tests were made in the three boreholes and in the new openings extended from an old tunnel existing in 450 m below surfaces. Various examination results are as follows: 1.Wall observation results showed that the looze zone was presumed I meter thick around the openings. 2. 2 meters thick of loose zone were indicated by the results of the effective polocity measurements. 3.0bservation results on the wall of boreholes using BIP System showed that a long numbers of open crucks was in the zone of I m from the wall and hair crucks tend to increase in the zone of 1 to 3.5 m from the wall. These results showed the looze zone was the renge of I to 3.5 m around the openings. 4.From the results of cell velocity by the Seismic Geotomography and of P-wave velocity change with depth on the boring core samples, the loose zone was estimated less than 2meters thick. On the basis of results of above-mentioned examinations, it is considered that the loose zone exsists in the renge of 2 to 3 m around the openings キーワード（英）： - 記事区分： - 区分 　　　委員会論文集