It is necessary to promote the use of soil generated by excavation of shield works as a recycled resource.
The generated soil is a construction by-product, and it is necessary to reuse it as a resource as much as possible based on the "Recycling Law" (1991).
There are the following methods to utilize the waste construction sludge.
① Use by yourself
② Paid sale
③ Utilization of recycling system (recycling designation system, recycling certification system)
Construction sludge may be recycled by intermediate treatment of construction sludge in order to contribute to waste control and environmental protection.In this case, it is necessary to carry out a content test of harmful substances and perform intermediate treatment according to the quality specified as the material, the required shape, etc. and the construction equipment of the shield.
When performing intermediate treatment, it is necessary to select the optimum treatment method in consideration of soil conditions, underground transportation method, shaft transportation method, shaft site area, disposal site conditions, etc. Procedures must be carried out for equipment such as dehydration treatment facilities that have the processing capacity required for notification.
The soil generated by the shield work must be properly treated and disposed of.
Of the materials discharged during the shield work, mud-like materials with high water content and fine particles are treated as inorganic sludge.Waste must be properly treated and disposed of in accordance with the "Waste Management Law".In general, a muddy state means a state in which a standard dump truck cannot be piled up and no one can walk on it. In this state, the cone index is approximately 200 kN as an index showing the strength of soil. / M2 or less, or uniaxial compression strength is about 50 kN / m2 or less.
In addition, when the contractor self-treats, he / she must comply with the treatment standards stipulated in the Waste Disposal Law.In addition, in the case of consignment processing, the consignment standards must be observed, such as confirmation of the permission of the consignee's industrial waste treatment business, conclusion of a consignment contract in writing, and issuance of an industrial waste management form (manifest).
* Example of muddy water circulation method
(Muddy water shield method, reverse circulation method)
(Reference: "Tunnel Standard Specification-Shield Construction Method Established in 2006", Japan Society of Civil Engineers)
(Environmental impact assessment)
Overview of the Japan-Korea Tunnel