J of Korean Tunn Undergr Sp Assoc 15(1)25-31(2013) eissn: 2287-4747 http://dx.doi.org/10.9711/ktaj.2013.15.1.025 pissn: 2233-8292 지하철터널유지관리계측센서의총손망실율산정연구 우종태 1 * 1 정회원, 경복대학교건설환경디자인과교수 A study on estimation of the total loss and damage ratio of maintenance monitoring sensor of subway tunnel Jong-Tae Woo 1 * 1 Dept. of Construction and Environmental Design, Kyungbok University, Professor ABSTRACT: In this study, the total loss and damage ratio of maintenance monitoring which is installed and operated in the domestic and foreign tunnel structure is researched and analyzed for estimating the loss and damage ratio of maintenance monitoring sensor of subway tunnel. The total loss and damage ratio at the elapsed time of 5-6 years after installation is 14.2% in the Seoul metro line no.5,6 and 7, 14.8% in the section 1 of the Seoul metro line no.9, 13.9% in the Channel tunnel of England and all of them are close to 15%. Therefore, it is reasonable to reflect that the total loss and damage ratio of maintenance monitoring sensor of subway tunnel is estimated provisionally 15% on design, and hence the study of the loss and damage ratio with the number of elapsed years in long-term by the measurement category will be needed. Keywords: Tunnel structure, Maintenance monitoring sensor, The total loss and damage ratio, The Seoul metro line no.5,6,7, and 9, Channel tunnel 요지 : 본논문은지하철터널유지관리계측센서의총손망실율을산정하기위해국내와국외의지하철터널구조물에설치되어운영중에있는유지관리계측센서의손망실현황을조사하고분석을실시하였다. 지하철터널유지관리계측센서설치후 5~6 년경과된시점을기준하여총손망실율은서울지하철5,6,7 호선에서 14.2%, 서울지하철 9호선 1단계구간에서 14.8%, 영국의 Channel tunnel 에서 13.9% 로모두 15% 에근접하게나타났다. 따라서지하철터널유지관리계측센서의총손망실율은잠정적으로 15% 로설정하여설계에반영하는것이타당한것으로판단되며, 향후장기간의경과년수에따른계측항목별손망실율연구가필요할것으로판단된다. 주요어 : 터널구조물, 유지관리계측센서, 총손망실율, 서울지하철 5,6,7,9 호선, Channel tunnel 1. 서론 최근들어건설계측기술은 IT산업및정보통신기술의급격한발달로거의모든건설현장에서적용이일반화되고있다. 또한사회기반시설의효율적인안전감시및유지관리를위해지하철, 도시철도, 일반및고속철도, 도로, 전력구, 통신구, 공동구등의터널 *Corresponding author: Jong-Tae Woo E-mail: jtwoo@kbu.ac.kr Received November 26, 2012; Revised December 18, 2012; Accepted January 11, 2013 구조물에유지관리계측시스템의도입과적용이증가되고있다 (Lee et. al., 2000; Woo J. T., 2009b). 일반적으로건설공사에서의계측은공사중계측과유지관리계측으로구분하고있다. 공사중계측은주로설계의불확정성요소등을보완하고설계의타당성을규명함으로써시공의안전성을확인하고경제성을확보할목적으로수행된다. 유지관리계측은공사중계측단계에서계측치가대부분수렴된상태를확인하고, 목적물인철근콘크리트구조물이시공되므로이미완공된구조물에대하 Copyright c2013, Korean Tunnelling and Underground Space Association This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativescommons.org/license/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
우종태 여공용중에지속적으로구조물의안전성확인과최적의유지관리가되도록객관적이고연속적인공학적판단자료를제공하여효율적이고경제적인구조물유지관리에기여하는것을목적으로수행되고있다 (Woo et. al., 2012a). 본논문은 1995년국내지하철터널유지관리계측센서가최초설치된서울지하철 5, 6, 7호선과 2006년설치된서울지하철 9호선 1단계구간의손망실율을분석하였으며, 국외의경우 1986년설치된영국의 Channel tunnel과 1995년설치된미국보스톤항의 Red line subway tunnel의손망실율을분석하여지하철터널유지관리계측센서의총손망실율을산정하고자연구를수행하여터널유지관리계측기술발전에기여하고자한다. 2. 건설계측센서의손망실율 ( 할증률, 고장률 ) 용어검토 국어사전에서손실 ( 損失 ) 이란축나거나잃어버리거나하여손해를보는것을말하며, 망실 ( 亡失 ) 이란잃어버리는것을의미한다. 고장 ( 故障 ) 이란기계나기구따위가정상적으로움직이지못하게된것을말한다 (Dong-a Publishing Co., 2010). 건설계측에서많이쓰이고있는손망실 ( 損亡失 ) 이란용어는국어사전에는없는용어이나, 취급부주의나기기적인결함으로인해정상적인작동이되지않은상태를의미하는용어로광범위하게사용되고있다. 건설계측에서 Redundancy( 여유분, 잉여분 ) 라는용어도자주사용되고있는데, 여유 ( 餘裕 ) 란넉넉하여남아있다라는뜻이며, 잉여 ( 剩餘 ) 는쓰고난나머지를뜻하는용어로손망실 ( 고장 ) 을고려한계측기기의추가수량을의미하는용어와는의미상차이가있는것으로보여사용에는적정하지않은용어로판단된다. 손망실율과유사한개념으로건설공사표준품셈에서는재료의할증률 ( 割增率 ) 이란용어가사용되고있 다. 이는시방서및도면에의하여산출된정미량 ( 正未量 ) 에재료의운반, 절단, 가공및시공중에발생되는손실량에가산해주는비율을말한다 (Woo et. al., 2012b). 건설계측에서센서 (Sensor) 또는게이지 (Gauge) 란대상의상태에관한측정량을신호로변화하는계의최초의요소로서계측기기에포함되며, 계측기기 (Measurement hardware) 는재료의감지소자에의해물리적에너지를전기또는빛에너지로변환하여자료의정보처리가되도록하는센서및게이지등을총괄하는용어를말하며, 계측시스템은계측자료획득시스템과계측자료전송시스템을포함하여계측에필요한모든장치및운용시스템을말한다 (Woo et. al., 2008). 건설계측기기의손망실원인중계측기기의성능불량, 설치시오류및보호불량, 작업자나시공장비의부주의에의한계측기기및연결케이블의손상등이확인된경우에는비교적책임소재가명확하나, 현장관리자가파손되는순간을직접목격하지못하였거나, 예상치못한과도한변형및응력발생으로계측불능상태가된경우에는책임소재가명확하지않아계측기기의재설치비용부담문제로마찰이발생하거나심지어는인위적인계측데이터를만드는일이발생할수도있다 (Nam S. S., 2000; Back et. al., 2002). 건설계측기기가최초설치시정상적으로작동되다가분명한이유없이계측값이이상치를나타내거나불안정한경우에는더욱마찰의대상이될수있다. 대부분의건설계측기기는열악한환경에설치되므로조건이양호한실내에서와달리내구수명이단축될뿐만아니라기술의한계로인하여고장이발생할수있다. 따라서건설계측에서일반적으로사용되는손망실율은할증률또는고장률과같은용어로사용이가능하다고판단되며, 합리적인손망실율 ( 할증률, 고장률 ) 을산정하여건설공사표준품셈에서재료에대한할증률개념으로활용이된다면건설계측으로인한이해당사자사이의마찰이상당부분해소되고원활한계측관리가수행될것으로기대된다. 26
지하철터널유지관리계측센서의총손망실율산정연구 3. 서울지하철터널유지관리계측센서의총손망실율분석 3.1 서울지하철 5, 6, 7 호선터널유지관리계측센서의총손망실율 서울지하철 5, 6, 7 호선건설공사도심지역공사구 간에대한터널유지관리계측센서의손망실율은 Table 1, 2와같으며, 1995년부터국내최초로터널유지관리계측센서가설치되었으며, 2000년 3월조사시점기준하여계측센서설치경과년수는 5~6 년이다. 유지관리계측센서는총 591개로구성비율은터널의라이닝응력계 54.7%, 터널의철근응력계 27.4%, 터널의토압계 9.5%, 터널의간극수압계 6.4%, 터널 Table 1. Summarization chart on loss and damage ratio of tunnel maintenance monitoring sensor of Seoul metro line no. 5, 6 and 7 (Standard for 2000. 03 : elapsed 5-6 years) (Unit: word count) Division Total Ratio Normal and damage and damage ratio Ranking led location Total 591 100.0 507 84 14.2 - - Earth pressure Tunnel natural 56 9.5 50 6 10.7 3 ground Piezo 38 6.4 36 2 5.3 5 Tunnel natural ground Rebar stress 162 27.4 142 20 12.3 2 Tunnel structure Lining stress Tunnel 323 54.7 268 55 17.0 1 structure Optical fiber Tunnel 12 2.0 11 1 8.3 4 sensor structure Table 2. and damage ratio of tunnel maintenance monitoring sensor of Seoul metro line no. 5, 6 and 7 by section (Nam S. S., 2000) (Standard for 2000. 03 : elapsed 5-6 years) (Unit: word count) Section Earth pressure l ation ratio Piezo Lining stress Rebar stress Optical fiber sensor Total l ation ratio l ation ratio l ation ratio l ation ratio l ation ratio 5-15 3 0 0 3 0 0 6 1 16.7 6 5 83.3 - - - 18 6 33.3 5-18 5 1 20.0 5 0 0 12 6 50.0 12 5 41.7 12 1 8.3 46 13 28.3 6-4 14 2 14.3 - - - 67 22 32.8 - - - - - - 81 24 30.0 6-5 4 0 0 4 1 25.0 12 0 0 12 0 0 - - - 32 1 3.1 6-6 10 2 20.0 - - - 84 19 22.6 3 0 0 - - - 97 21 22.0 6-9 4 1 25.0 4 0 0 12 0 0 12 0 0 - - - 32 1 3.0 6-10 - - - - - - 90 7 7.7 90 9 10.0 - - - 180 16 9.0 7-19 - - - - - - - - - 8 0 0 - - - 8 0 0 7-20 - - - 2 0 0 3 0 0 4 0 0 - - - 9 0 0 7-21 - - - 4 0 0 12 0 0 - - - - - - 16 0 0 7-23 - - - - - - - - - 6 1 16.6 - - - 6-16.6 7-24 16 0 0 16 1 6.2 25 0 0 - - - - - - 57 1 1.8 7-25 - - - - - - - - - 4 0 0 - - - 4 0 0 7-26 - - - - - - - - - 5 0 0 - - - 5 0 0 Total 56 6 10.7 38 2 5.3 323 55 17.0 162 20 12.3 12 1 8.3 591 84 14.2 Total loss and damage ratio = (loss and damage number / installation number) 100 = (84 / 591) 100 = 14.2% Rank 3 5 1 2 4-27
우종태 의광섬유센서 2.0% 이다 (Nam S. S., 2000). 총손망실율은 14.2% 이며, 공구별로손망실율은최소 0.0% 에서최대 33.3% 로큰차이를보였으나, 1995년 8월부터 9월까지 1개월간영등포 (5-15공구) 에서마포구간 (5-18) 이집중호우로인한우수유입으로터널전체가침수되어이로인한계측센서의손망실이큰것으로판단된다. 총손망실율은 14.2% 이며, 계측센서별손망실율은터널의라이닝응력계 17.0%, 터널의철근응력계 12.3%, 터널의토압계 10.7%, 터널의광섬유센서 8.3%, 터널의간극수압계 5.3% 순서로나타났다. 3.2 서울지하철 9 호선 1 단계구간터널유지관리계측센서의총손망실율 서울지하철 9호선건설공사 1단계구간에대한터널유지관리계측센서의손망실율은 Table 3, 4와같으며, 2006년부터유지관리계측센서가설치되었으며, Table 3. Summarization chart on loss and damage ratio of tunnel maintenance monitoring sensor of Seoul metro line no.9 on 1 stage by section (Standard for 2011. 08 : elapsed 5-6 years) (Unit: word count) Division Total Ratio Normal and damage and damage ratio Ranking led location Total 655 100.0 558 97 14.8 - - Earth pressure 18 2.7 17 1 5.6 6 Tunnel natural ground Piezo 66 10.1 53 13 19.7 3 Tunnel natural ground Rebar stress 148 22.6 132 16 10.8 4 Tunnel structure Lining stress 294 44.9 270 24 8.2 5 Tunnel structure Segment stress 73 11.1 45 28 38.4 1 Shield tunnel Concrete stress 56 8.6 41 15 26.8 2 Box structure Table 4. and damage ratio of tunnel maintenance monitoring sensor of Seoul metro line no.9 on 1 stage by section (Standard for 2011. 08 : elapsed 5-6 years) (Unit: word count) Sec tion Earth pressure lation ratio Piezo lation ratio Concrete stress lation ratio Rebar stress lation ratio Lining stress lation ratio Segment stress lation ratio Total lation ratio 901 8 1 12.5 8 1 12.5 0 0 0.0 61 4 6.6 48 0 0.0 0 0 0.0 125 6 4.8 902 0 0 0.0 2 2 100 16 6 37.5 16 0 0.0 5 1 20.0 0 0 0.0 39 9 23.1 903 10 0 0.0 4 1 25.0 0 0 0.0 10 2 20.0 20 1 5.0 0 0 0.0 44 4 9.1 904 0 0 0.0 2 0 0.0 8 2 16.7 8 2 16.7 0 0 0.0 0 0 0.0 18 4 22.2 905 0 0 0.0 0 0 0.0 10 1 10.0 5 1 20.0 0 0 0.0 0 0 0.0 15 2 13.3 906 0 0 0.0 12 2 16.7 4 0 0.0 34 5 14.7 60 7 11.7 0 0 0.0 110 14 12.7 907 0 0 0.0 0 0 0.0 4 3 75.0 4 2 50.0 0 0 0.0 0 0 0.0 8 5 62.5 908 0 0 0.0 0 0 0.0 8 3 37.5 4 0 0.0 0 0 0.0 0 0 0.0 12 3 25.0 909 0 0 0.0 0 0 0.0 0 0 0.0 0 0 0.0 0 0 0.0 73 28 38.4 73 28 38.4 910 0 0 0.0 6 2 33.3 0 0 0.0 0 0 0.0 45 1 2.2 0 0 0.0 51 3 5.9 911 0 0 0.0 4 0 0.0 6 0 0.0 6 0 0.0 20 1 5.0 0 0 0.0 36 1 2.8 912 0 0 0.0 12 2 16.7 0 0 0.0 0 0 0.0 62 7 11.3 0 0 0.0 74 9 12.2 913 0 0 0.0 14 2 14.3 0 0 0.0 0 0 0.0 24 4 16.7 0 0 0.0 38 6 15.8 914 0 0 0.0 2 1 50.0 0 0 0.0 0 0 0.0 10 2 20.0 0 0 0.0 12 3 25.0 total 18 1 5.6 66 13 19.7 56 15 26.8 148 16 10.8 294 24 8.2 73 28 38.4 655 97 14.8 Total loss and damage ratio = (loss and damage number / installation number) 100 = (97 / 655) 100 = 14.8% Rank 6 3 2 4 5 1-28
지하철터널유지관리계측센서의총손망실율산정연구 2011년 8월조사시점기준하여계측기기설치경과년수는 5~6년이다. 유지관리계측센서는총 655개로구성비율은터널의라이닝응력계 44.9%, 터널의철근응력계 22.6%, 쉴드터널의세그먼트응력계 11.1%, 터널의간극수압계 10.1%, 박스구조물의콘크리트응력계 8.6%, 터널의토압계 2.7% 이다 (Woo J. T., 2009a, 2010b). 총손망실율은 14.8% 이며, 공구별로손망실율은최소 2.8% 에서최대 62.5% 로큰차이를보였으며, 2006년 7월부터약 15일간 908공구구간이집중호우로안양천제방이유실되어터널전체가침수로인한계측기기의손망실이큰것으로판단된다. 총손망실율은 14.8% 이며, 계측센서별손망실율은쉴드터널의세그먼트응력계 38.4%, 박스구조물의콘크리트응력계 26.8%, 터널의간극수압계 19.7%, 박스구조물의철근응력계 10.8%, 터널의라이닝응력계, 8.2%, 터널의토압계 5.6% 순서로나타났다. 3.3 서울지하철 5, 6, 7, 9 호선터널유지관리계측센서의총손망실율비교분석 서울지하철 5, 6, 7호선건설공사도심지역공사구간에대한터널유지관리계측센서의 1995년설치후 5~6년이경과된 2000년 3월기준총손망실율은 14.2% 이며, 공구별로손망실율은최소 0.0% 에서최대 33.3% 로큰차이를보였다. 서울지하철 9호선 1단계구간에대한터널유지관리계측센서의 2006년설치후 5~6 년이경과된 2011 년 8월기준총손망실율은 14.8% 이며, 공구별로손망실율은최소 2.8% 에서최대 62.5% 로큰차이를보였다. 위의분석내용을보면계측센서설치후 5~6년이경과된서울지하철 5, 6, 7, 9호선터널유지관리계측센서의총손망실율은 14.2~14.8% 로약 15% 에근접한값을보이며, 향후장기간의경과년수에따른손망실율연구가필요할것으로판단된다. 4. 국외터널유지관리계측센서의손망실율분석 4.1 Channel tunnel (Euro tunnel) Channel tunnel은총연장 50.45 km, 해저깊이평균 45 m, 단면크기는주터널직경 7.6 m, 서비스터널직경 4.8 m, 건설기간은 1986년에서 1994년까지약 7년이소요되었다. 터널유지관리계측은총 14단면으로주터널에 7단면, 서비스터널에 6단면, 주터널과서비스터널을연결하는횡갱에 1단면이며, 1986년에 231개진동현식변형률계를세그먼트라이닝에설치하여 1990년까지 5년경과후손망실수량은 32개로손망실율은 13.9% 를보였고, Channel tunnel 유지관리계측센서의손망실율은 Table 5과같다 (Meller.S, 1990). 4.2 Red line subway tunnel 미국보스톤항의 Red line subway tunnel은연장 366 m, 굴착깊이 19.7 m이며, 굴착단면은단선병렬터널로외경 6.7 m, 콘크리트라이닝내경 5.0 m이다. 지하철터널유지관리계측센서는다양한종류를설치하였는데 1995년에 200개의진동현식변형률계 Table 5. and damage ratio of tunnel maintenance monitoring sensor about Channel tunnel (Standard for 1990 : elapsed 5 years) VWSG : Vibrating Wire Strain Gauges Division lation number and damage number and damage ratio Segment lining stress 231 32 13.9 and damage ratio (loss and damage number / installation number) 100 = (32/231) 100 = 13.9% 29
우종태 Table 6. and damage ratio of tunnel maintenance monitoring sensor about Red line subway tunnel (Standard for 1997 : elapsed 3 years) Division lation number and damage number and damage ratio Total 839 34 4.1 - Concrete lining stress (Vibrating Wire Strain Gauges) 200 10 5.0 4 Crack 506 8 1.6 5 Liquid level gauge 106 9 8.5 3 Liquid density gauge 19 5 26.3 1 Flow 8 2 25.0 2 and damage ratio (loss and damage number / installation number) 100 = (34/839) 100 = 4.1% Rank 를콘크리트라이닝에설치하였고, 1997년까지약 3년경과후손망실수량은 10개로손망실율은 5.0% 를보였고, Red line subway tunnel 유지관리계측센서의손망실율은 Table 6와같다 (Feldman et al., 1999). Channel tunnel과 1995년설치된미국보스톤항의 Red line subway tunnel의손망실율을분석하여지하철터널유지관리계측센서의총손망실율을산정하고자연구를수행하였으며, 연구결과는다음과같다. 4.3 국내와국외터널유지관리계측센서의손망실율분석 Channel tunnel 유지관리계측은 231개진동현식변형률계를 1986년에콘크리트라이닝에설치하였고, 1990년까지 5년경과후손망실수량은 32개로손망실율은 13.9% 를보여서울지하철 5, 6, 7, 9호선의총손망실율 14.2~14.8% 과유사하게 15% 에근접한값을나타냈다. 따라서터널유지관리계측센서의총손망실율은 15% 로설정하는것이타당한것으로판단되며 (Woo J. T., 2010a), 향후장기간의경과년수에따른추가적인손망실율연구가필요할것으로판단된다. 5. 결론 본논문은 1995년국내지하철터널유지관리계측센서가최초설치된서울지하철 5, 6, 7호선과 2006년설치된서울지하철 9호선 1단계구간의손망실율을분석하였으며, 국외의경우 1986년설치된영국의 1. 건설계측에서일반적으로사용되는계측센서의손망실율은할증률또는고장률과같은용어로사용이가능하다고판단되며, 합리적인손망실율 ( 할증률, 고장률 ) 을산정하여건설공사표준품셈에서재료에대한할증률개념으로활용이된다면건설계측으로인한이해당사자사이의마찰이상당부분해소되고원활한계측관리가수행될것으로기대된다. 2. 서울지하철 5, 6, 7호선건설공사도심지역공사구간에터널유지관리계측센서설치후 5~6 년경과된시점을기준하여총손망실율은 14.2% 로나타났다. 3. 서울지하철 9호선건설공사 1단계구간에터널유지관리계측센서설치후 5~6년경과된시점을기준하여총손망실율은 14.8% 로나타났다. 4. 국내서울지하철 5, 6, 7, 9호선의총손망실율은 14.2~14.8% 이며, 국외 Channel tunnel의손망실율은 13.9% 로모두 15% 에근접한값을나타냈다. 따라서터널유지관리계측센서의총손망실율은잠정적으로 15% 로설정하는것이타당한것으로 30
지하철터널유지관리계측센서의총손망실율산정연구 판단된다. 5. 현장타설콘크리트라이닝응력계의손망실율은 국내가 8.2~17.0% 이나, 국외는 5.0% 이며, 세그 먼트콘크리트라이닝응력계의손망실율은국내 가 38.4% 이나, 국외는 13.9% 로큰차이를보여 이는시공수준의차이및국산계측기기의내구성 문제등의영향으로판단된다. 6. 향후장기간의경과년수에따른추가적인손망실 율연구와국내및국외의계측센서에대한계측항 목별손망실율연구가필요할것으로판단된다. 감사의글 이논문은 2011년정부 ( 교육과학기술부 ) 의재원으로한국연구재단의지원을받아수행된기초연구사업일반연구자지원사업기본연구지원사업 ( 유형Ⅱ, 과제번호 2011-0009456) 으로 건설및터널계측기술의공학적응용을위한핵심요소기술개발 의 2012 년 2차년도연구과제 ( 과제번호 2012-0002684) 인 건설계측기기의손망실비율산정연구 의일부내용이며, 이에감사를드립니다. 참고문헌 1. Back, K.H., Oh, Y.S., Kim, Y.J., Kim, Y.G. (2002), A study on efficiency of tunnel maintenance monitoring, Journal of Korean Tunnelling and Underground Space Association, Vol. 4, No. 4, pp. 355-369. 2. Dong-a Publishing Co. (2010), Dong-a New Korean Dictionary. 3. Feldman., A.I., Buechel, G.J. (1999), Instrumentation program for Boston red line tunnel, 5th International Symposium on Field Measurements in Geomechanics, pp. 95-100. 4. Lee, D.H., Han, I.Y., Kim, G.S., Jin, S.W. (2000), Case studies on applications of convergence measurement system at the stages of tunnel construction and maintenance, Journal of Korean Tunnelling and Underground Space Association, Vol. 2, No. 3, pp. 59-69. 5. Meller, S. (1990), Monitoring of channel tunnel instrumentation, Gage Technique Ltd., pp. 1-31. 6. Nam, S.S. (2000), Case studies on the damage ratio of monitoring sensor, Korean Geotechnical Society Spring Conference at Information Technical Committee. 7. Woo, J.T., Lee, R.C. (2008), Construction monitoring engineering, Goomi Publishing Co., pp. 15-25. 8. Woo, J.T. (2009a), Final report of recently technical maintenance monitoring in the section 1 of the Seoul metro line no.9, Seoul Metropolitan Infrastructure Headquarters, pp. 1-6. 9. Woo, J.T. (2009b), A study on comparison of a ground water influx quantity in Seoul subway tunnel, Journal of Korean Tunnelling and Underground Space Association, Vol. 11, No. 4, pp. 353-359. 10. Woo, J.T. (2010a), A study of the present state analysis and development plans about construction monitoring and monitoring industry, Journal of Korean Society of Civil Engineers, Vol. 30, No. 2D, pp. 163-169. 11. Woo, J.T. (2010b), Analysis techniques toward monitoring Seoul city subway line no.9 maintenance monitoring by the joint study with Industry-University - Institute, Korea Institute for Structural Maintenance and Inspection Spring Conference, pp. 40-43. 12. Woo, J.T., Lee, K.I. (2012a), A study on establishment of measurement and analysis frequency of maintenance monitoring in tunnel, Journal of Korean Tunnelling and Underground Space Association, Vol. 14, No. 2, pp. 117-129. 13. Woo, J.T., Park, J.H., Ji, H.S. (2012b), Estimation of construction, Kimoondang Publishing Co., pp. 47-58. 31