ABSTRACT

Supply facilities have to be buried due to urban development from rapid population growth and a lack of land; therefore, vertical shaft construction has increased for utility tunnels. Because utility tunnels are installed in urban areas, there can be critical problems from faulty construction. Conventional construction methods used in most vertical shafts cause a decrease in the groundwater level which is one reason for ground settlement. Therefore, construction methods have been researched that take into consideration the ground settlement of vertical shafts, and the ring cut method was developed. This method first penetrates an outer section of the shaft to prevent soil inflow and extends the seepage line. Using this method, ground settlement caused by construction is expected to decrease. This study performed 2-dimensional stress-seepage coupled numerical feasibility tests to analyze the effective penetration depth of the ring cut method. Settlement and seepage were measured to evaluate its performance. The obtained data will be used to optimize the newly developed method.