© ÖGG.The main structure of the Poligon station, which is situated on route of Üçyol-Üçkuyular line as part of Izmir subway development works consists of diaphragm wall. Under the diaphragm wall, a tunnel is planned for docking the train to the station. Several old buildings with 8-10 stories are located near by the station structure. Many of which are not suited to new earthquake legislation. Condition of bed of tunnel is an alternation of claystone and sandstone, which consist of very weak and very strong units. Therefore, fore-support design was realized in this highly complex work environment in order to save the construction equipment and re-excavate T2 tunnel without damaging the structure of the station, substructure and surrounding buildings. In general, design system proposed here includes classical support systems, chemical injection and micro-cement injection. In this study, field studies for cross-failure at İzmir Subway Poligon Station, measurements, assessments, excavation and support design, which are suggested to re-excavate T2 tunnel are explained in detail.