Extra-Long DSM Columns for Post-Collapse Stabilization of a Tunnel Constructed in Weak Ground
Geotechnical and Geological Engineering, cilt.44, sa.6, 2026 (ESCI, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 44 Sayı: 6
- Basım Tarihi: 2026
- Doi Numarası: 10.1007/s10706-026-03811-5
- Dergi Adı: Geotechnical and Geological Engineering
- Derginin Tarandığı İndeksler: Emerging Sources Citation Index (ESCI), Scopus, Applied Science & Technology Source, Compendex, Geobase, INSPEC, Natural Science Collection (ProQuest), Earth, Atmospheric, & Aquatic Science Collection (ProQuest), Engineering Source (EBSCO), Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Anahtar Kelimeler: Deep soil mixing, Failure, Finite element, Tunnel, Weak ground
- Gazi Üniversitesi Adresli: Evet
Özet
The Karaman-Ulukışla Railway Project in southern Türkiye includes the Karaman T-2 (Çakmak) Tunnel, which traverses weak clay units with medium to stiff consistency, reaching thicknesses of up to 60 m. During tunnel excavation, a significant failure occurred in weak ground, producing a circular surface subsidence with a diameter of approximately 40 m and a depth exceeding 1.2 m. This study investigates the failure mechanisms and assesses the feasibility, applicability, and performance of an unconventional deep soil mixing (DSM) ground improvement method using 60 m-long columns—an approach rarely implemented in practice. Two- and three-dimensional finite element models, calibrated with field and laboratory data, confirmed the agreement between observed deformations and computed results. The analyses demonstrated that DSM significantly enhanced ground rigidity, necessitating a reassessment of excavation classification and enabling a more cost-effective tunnel design. Following ground improvement with DSM columns, the tunnel support system was revised from C-3 to B-3. Monitoring during excavation with the B-3 system recorded a maximum deformation of 21 mm. This modification resulted in approximately 15% time savings and 25% cost savings in the DSM-improved tunnel section.