늪지 및 계곡수와 터널공사의 상관성 분석 : 경부고속철도 천성산구간 원효터널 중심으로 = Analysis of Correlation Between Tunnel Works and Swamp/Valley Streams

다국어 초록 (Multilingual Abstract)

The Wonhyo Tunnel on KTX railroad line is a section of latest concerns from domestic environmental NGOs, which focus on potential destruction of ecosystem or the like due to ever-depleted swamp water and valley streams at about 300m upward from the tunnel under construction.
In order to investigate possible effects of tunnel works upon swamp and valley streams, this study first analyzed promising mechanisms for keeping riverhead at swamps through drilling survey and physical exploration to find out possible causes of swamp, its physical properties and more.
Second, this study determined the range affected by ground water sink when carrying out tunnel works by enhancing leaky sections with grouting and the like according to tunnel plan.
Third, this study analyzed the results of monitoring before and during work to determine possible associations between tunnel works and swamp/valley streams.
As a result, out of all swamps in the vicinity of the tunnel, it was found that Mujechi 1st and 2nd swamps have been getting smaller in their area little by little since 50 years ago primarily under the influence of eroded streams around lower swamp and even ever-increasing annual mean temperature.
As the result of monitoring about swamp before work, it was found that swamp water depends absolutely on amount of rainfall.
Besides, the results of monitoring during work also didn’t show any leakage generated in the tunnel during and after excavation works with regard to a wheat field swamp in the most vicinity of the tunnel (80m away).
On the other hand, it was found that the range affected by ground water sink in tunnel section without grouting process amounted to about 100m around the tunnel, which indicates that such ground water sink has no significant impact upon most of swamps near the tunnel.
As the result of testing by two well tracer test around swamps, it was noted that swamp water didn't run out from the bottom of swamp even with adjacent ground water level sunk in factitious ways.
And the results of physical survey showed that swamp kept saturated even in dry season when ground water level becomes lower than the bottom of swamp.
Therefore, even supposing that ground water level becomes sunk due to tunnel works, it is estimated that the water level of swamps would be still kept owing to impervious layer(peat beds).
This study also covered monitoring about the water level of valley stream before work in terms of the valleys scattered around Wonhyo Tunnel.
As a result, it was found that the amount of valley water is absolutely influenced by rainfall. And the results of monitoring during work showed that the valley water at Bosam town in the vicinity of tunnel entry did not vary in its volume even after tunnel excavation works.
Finally, this study covered hydraulic test about Gancheon valley section, which is very low in height (about 20m lower than tunnel) out of valleys distributed around Wonhyo Tunnel, and thus is likely to get an inflow of valley water into the tunnel via adjacent fault zone.
As a result, it was found that the amount of valley water inflow into the tunnel upon grouting works reached 0.15%～0.2% of valley water flow during winter(dry) season. Hence, it is estimated that valley water amount would be still kept owing to be very little inflow of valley water into the tunnel.

목차 (Table of Contents)

• 제 1 장 서론 1
• 1.1 연구배경 및 목적 1
• 1.2 연구동향 2
• 1.3 연구범위 3
• 제 2 장 자연생태 및 지질특성 5
• 2.1 천성산구간 자연생태 5
• 2.2 경부고속철도 원효터널 13
• 2.3 지질구조 14
• 2.4 단층 및 파쇄대 18
• 2.5 터널 시공방법 30
• 제 3 장 늪지, 계곡부 조사 및 시험 35
• 3.1 늪지 및 계곡부 현황 35
• 3.2 시추조사 및 물리탐사 48
• 3.3 실내 및 실외시험 64
• 3.4 수리학적 안정성 해석 74
• 제 4 장 모니터링 및 터널굴착 분석 82
• 4.1 모니터링 현황 82
• 4.2 공사전 모니터링 83
• 4.3 공사중 모니터링 88
• 4.4 터널굴착시 지하수 유출 94
• 제 5 장 늪지 및 계곡수에 대한 터널공사의 영향 99
• 5.1 터널굴착이 늪지에 미치는 영향 99
• 5.2 터널굴착이 계곡수에 미치는 영향 105
• 제 6 장 결론 108
• 참고문헌 110
• Abstract 112