Outline of Japan-Korea Tunnel Plan-Environmental Assessment (Environmental Impact Assessment)-

Tunnel standard specification / shield method (groundwater countermeasures / prevention of oxygen deficiency)

Groundwater measures

If there is a risk of affecting groundwater due to construction work, a thorough investigation must be conducted and appropriate measures must be taken as necessary.



When the groundwater level lowering method, the pressure method, the chemical injection method, etc. are used together, or the mud-type shield near the well, etc., is spilled or backfilled, the groundwater may be affected.Therefore, it is necessary to investigate the groundwater utilization situation in the surrounding area before the construction starts and take appropriate measures against the impact that may occur.

Survey item

(XNUMX) Investigate the water level, water quality, flow direction, etc. of the surrounding ground and groundwater, and grasp the overall tendency (see Article XNUMX of the same).

(XNUMX) Investigate the existence of wells, ponds, and reservoirs in the vicinity and their usage status.In particular, carefully investigate wells for domestic and commercial water.

(1974) When injecting chemicals, conduct a survey based on the survey items of the former Ministry of Construction "Temporary Guidelines for Construction Work by Chemical Injection Method" (XNUMX).


① Adoption of auxiliary construction method
Water is blocked by appropriate auxiliary methods such as pressure air method, chemical injection method, freezing method, and impermeable wall to prevent the groundwater level in the surrounding area from dropping.In this case, in addition to the soil condition, the appropriate auxiliary construction method should be selected in consideration of the soil cover, the composition of the entire ground, and the environmental conditions such as the surrounding wells.

② Prevention of groundwater pollution by injecting chemicals
Chemical injection must be carried out while monitoring the condition of water pollution by providing side points around it.For details, refer to the former Ministry of Construction "Temporary Guidelines for Construction Work by Chemical Injection Method" (1974).

Prevention of anoxia

When work is carried out by the pneumatic method, it is necessary to conduct a survey in advance and take appropriate measures to prevent the influence of leakage of oxygen-deficient air, etc. on the surrounding area.



When work is carried out by the pressure construction method, oxygen-deficient air or harmful gas may leak to nearby wells, basements or other underground construction sites depending on the ground conditions, so appropriate investigations and countermeasures based on relevant laws and regulations Must be taken.In addition, if the stratum contains harmful gases such as methane and hydrogen sulfide, risk factors will increase, so it is necessary to take additional measures.

Related regulations

(24) "Rules for Prevention of Anoxia, etc .: Article XNUMX (Measures Related to Pressure Air Construction Method)" stipulates surveys, measurements, prevention measures, etc. when working by the pressure air construction method in places where there is a risk of oxygen deficiency.

(21) The "Industrial Safety and Health Law Enforcement Ordinance: Article XNUMX" stipulates the appointment of a work chief for work in areas where oxygen deficiency is dangerous, and requires measurement of the work environment.In addition, the place where oxygen deficiency is dangerous is specified in Appendix XNUMX of the Enforcement Ordinance.


① Preliminary survey and examination
As a result of soil and groundwater investigation (see Article XNUMX), if there is a risk of leakage of oxygen-deficient air, etc., investigation and examination for accident prevention such as investigation of obstacle properties within the affected area (see Article XNUMX) Must be done.

② Preventive measures
Measure the oxygen concentration in the air and ensure monitoring of wells, basements, and other locations within a XNUMXkm radius where there is a risk of leakage.If it is necessary to avoid the effects of exposure, take appropriate preventive measures and safety measures.
(Reference: "Tunnel Standard Specification-Shield Construction Method Established in 2006", Japan Society of Civil Engineers)

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