kigam 1 overview of geological situation for a possible t2kk detector site 2006. 07. 14 chang-ha ryu...
TRANSCRIPT
KIGAM 1
Overview of geological situation for a possible T2KK detector site
2006. 07. 14
Chang-Ha Ryu
Geotechnical DivisionKorea Intitute of Geoscience & Mineral Resources (KIGAM)
韓 國 地 質 資 源 硏 究 院
2nd International Workshop on a Far Detector in Korea for the J-PARC Neutrino Beam
July 13 - 14. 2006, International Conference Hall, SNU
KIGAM 2
General procedure
Preliminary data collection - preliminary assessment - preliminary geotechnical characterization
Feasibility study - engineering classification of rock mass - feasibility assessment of tunneling problems & alternatives
Detailed site characterization
Stability analyses
Final design and construction
Feedback loop
KIGAM 3
Requirements
Area between 2.0 and 2.5 degree off-axis beam ( < 1 deg. ?) Depth: ~ 1,000 m (uniform overburden in all direction) Size of underground research module: 50 m (dia.) x 280m (l)
cylindrical opening
Long term safe operation Effective (economic) construction Research module in good rock mass
KIGAM 4
JPARC
Off-axis angle
2.5deg.off-axis beam @Kamioka
2.0 deg. off axis2.0 deg. off axis
2.5 deg. off axis2.5 deg. off axis
Requirements_Location
KIGAM 6
Overview of General Geology
Throughout the country, mountains are not high, rarely exceeding 1,200 meters, but they are found almost everywhere. The terrain is rugged and steep, and only near the west and southwest coasts are extensive flat alluvial or diluvial plains and more subdued rolling hilly lands.
Korea consists largely of the Precambrian rocks, such as granite gneisses and other metamorphic rocks. The Gyeongsang Supergroup is distributed across a wide area within the Gyeongsang-do province which is one of the area of our concerns.
The Gyeongsang Supergroup is composed of the Sindong and Hwayang groups and the Bulguksa Intrusives. The biotite granite intruded in the Gyeongsang Supergroup is called Bulguksa Granite.
Hwayang Group widely distributed throughout the Gyeongsang-do province, consists of conglomerates, sandstone, shale, and volcanic rock such as andesite, basalt, rhyolite, and tuff, especially in the upper part of the group.
KIGAM 7
Site Consideration 1
Overburden: 1 km deep
Preferrable site: mountain, mine, tunnel
Easy slope topograpy requires
- excavation of long tunnel to satisfy gradient condition
- shaft, inclined shaft
too costly !
KIGAM 8
Mine Site
Advantages of utilizing abandoned mine
Reduce costs Minimize environmental impacts Minimize complaints from residents and
environmentalist Easy to get approval and
to get support from local government Easy to get information on geological conditions
KIGAM 9
URLs for Astrophysics Research_Mine SiteSoudan URLOld iron mine in MinesotaDepth : 710m (2,080mwe)Exp. Lab. : 15m x 13m x 82m
Boulby Mine Lab. - UK Location : Boulby mine, ClevelandDepth : 1,100m
CUPP Lab. - Finland Location : Outokumpu mine, PyhasalmiDepth : 90~970m (current)
SNO (Sudbury Neutrino Observatory) – CanadaLocation : Creighton mine, SudburyDepth : 2,039m
KIGAM 10
URLs for Astrophysics Research_Tunnel Site
LSC-SpainLSC-Spaininside Somport tunnel (Spain – France), Canfrancinside Somport tunnel (Spain – France), CanfrancDepth : ~ 900mDepth : ~ 900m
LNGS (Gran Sasso National Lab.) – Italybesides Gran Sasso tunnel (Teramo – Rome)Depth : 1,400m Experiment halls : L=100m, H=18m,
KIGAM 17
Bohyeon San (1124m)
Site Consideration_2005
Bohyeon San in Youngcheon ~1,045 km, 2.0o off, 1124 m highNational Astronomy Observatory on top
KIGAM 18
Possible Site: <1 degree off-axis
Guryongpo in Pohang (Gyeongbuk Province) < 1,000 km < 1.0o off, no mountains (sea level)
Toham San in Gyeongju 1,000 km 1.0o off, ~500 m high mountains (National Park)
KIGAM 19
Description of Geology
EON YANG Sheet:
High mountaineous districts includes the peaks of Gajisan(1240m), Shinbulsan(1208m), in the western part, underlain by andesite, granite, and other rocks
GI GAE Sheet:
Southern marginal portion of the Taeback Mountain Range; the highest peak 960m(Giryoungsan); Bohyounsan(839m), Suseokbong(820m), Chimgoksan 725m, Unjusan 807m; the area is underlain by Cretacous sedimentary, volcanic and plutonic rocks- granite, granodiorite, andesite, rhyolite …
KIGAM 21
Other Sites
SHINSHEUNG Sheet: Noreong mountain range, many peaks attain heights of betw
een 400-760m; Sinseon-bong(763m), Choowolsan; gneiss, granite, sedimentary and volcanic rocks
MIRYANG Sheet There are comparatively high peaks of Togoksan(855m), Yo
msubong(816m), Muchoksan(700m), Chontaesan(631m), Kumosan(760m), Hyangrobong(727m), Manosan(670m) etc.
The geology of the area is composed of Yuchon Group and Bulguksa Intrusive rocks. The Yuchoon group is divided into andesitic rocks (andesite, ruff), and rhyolitic rocks (rhyolite, tuff); Miryang andesite is distributed on a large scale.
KIGAM 22
Possible Site: <1 degree off-axis
Geological map – Guryogpo/Yeonil Sheet
1:50,000 geological maps of these area: unavailable
Geological data and some detailed site information available
high speed rail way construction roadway construction
KIGAM 23
Mines
1 1 Gyeongnam-do
1 4 1 1 Gyeongbuk-do
2 2 Jeonnambuk-do
1 3 8 Chungnam-do
4 4 Chungbuk-do
2 2 1 Gyeonggi-do
3 7 6 5 3 1 5 Gangwon-do
D C B A D C B A
Metal, Non-metal mine Coal mine Province
EX) List of Metal Mines in MUJU-gun (source: KIGAM Mine DB)가옥 , 강창 , 고길 , 금령 (2), 길산 , 동왕 (1), 무주 , 봉소(2), 삼가 (1), 삼가 (3), 삼가리 , 삼봉 (3), 삼성 (3), 세창 (2), 승륭 , 쌍봉 (1), 쌍봉 (2), 쌍봉 (3), 영성 , 오동 , 오산 (2), 월성 , 적상 , 전일 (1), 제국 (1), 창덕 (1), 태성 , 태정
Abandoned Mines
* Possibility of utilization: A>B>C>D (source: KIGAM report, 2004)
Mine layout, Samga mine
KIGAM 24
Abandoned Quarry near Miryang
Location: Gyeongsangbuk-do Cheongdo-gun Rock type: AndesiteUni-axial compressive strength: 1,500 ~ 1,600 kgf/cm2
~ 1.5 km
quarry
tunnel
KIGAM 26
Concluding Remarks
Possible sites - mountain area - need to investigate mines thoroughly, and then find new site
Geological conditions - favorable - if poor but no other choice, solve by engineering - more detailed geotechnical characterization needed to reduce potential risks for construction
KIGAM 27
Concluding Remarks
Factors affecting the stability of tunnels
- stress fields
- mechanical properties of rock: strength, E …
- structural characteristics: joints, faults
- groundwater conditions
- method and quality of excavation
- support of rock strata
- size and shape of tunnel, underground chamber