The tunnel excavation passed under the existing rail way has been increased in the process of improving the urban environment. These tunnel excavation has to make to be assured for the safety of the train operation and the stability of the tunnel excavation.
The KTX tunnel excavation which is builded a new tunnel under Kyungbusun rail way is reviewed upon the safety of the train operation and the stability of the tunnel excavation in this study.
The safety criterion of the train operation is determined through the investigation of the maintenance management standards of the railway track. The stability standards of the tunnel excavation is determined through the investigation of the structural stability for the shotcrete and the geotechnical stability. The crown settlement and the convergency of a tunnel are reviewed to check the tunnel stability. The absolute settlement of railway subbase and the differential settlement of railway track is reviewed for the line alignment and the face alignment of railway track. The safety of the train operation during the construction of new KTX tunnel is confirmed through the review of the 2 dimensional numerical analysis results.
The more the overlapped length between KTX tunnel area and Kyungbusun rail way increases, the absolute settlement of railway subbase and the differential settlement of railway track for the line alignment are increased. Also the overlapped length increases, the horizontal displacement and the differential displacement of railway track for the face alignment are increased. It is shown that the subbase settlement and the rail track settlement is estimated to be developed within the allowable settlement. The overlapped length decreases, the absolute settlement of railway subbase and the differential settlement of railway track for the line alignment are decreased. Also the overlapped length decreases, the horizontal displacement and the differential displacement of railway track for the face alignment are decreased. The more the lateral stress coefficient Ko increases, the railway subbase settlement is decreases and the horizontal displacement of railway track is increases. The railway subbase settlement and the horizontal displacement of railway track estimated in the closed invert tunnel section is smaller than that estimated in the non-closed invert tunnel section. This means that the closed invert tunnel section is better for the train operation safety and the tunnel excavation stability than in the non-closed invert tunnel section.