| Title |
Analysis of Long-Term Durability and Environmental Impact of Shield TBM Inorganic Thixotropic Backfill |
| Authors |
장성민(Jang, Seong Min );박진성(Park, Jin Seong);유용선(Ryu, Yong Sun);최병훈(Choi, Byoung hoon);정혁상(Jung, Hyuk Sang) |
| DOI |
https://doi.org/10.12652/Ksce.2025.45.1.0081 |
| Keywords |
무기질계 가소성 뒤채움재; 쉴드 TBM; 에트린자이트; LW 공법 |
| Abstract |
The study analyzes the performance of ITB (Inorganic Thixotropic Backfill) grout, which exhibits properties of reducing leaching and plasticity, through experimental research. It also compares this with the existing TBM backfill method, LW method. The results of unconfined compressive strength tests showed that the ITB grout, when dry curing, exhibited approximately 12 times higher strength than the LW method at the initial curing age (1 hour), and about 7 times higher strength when cured underwater. At the long-term curing age (1 year), it maintained a strength of over 3 MPa regardless of the curing method. Additionally, XRD tests indicated that Ettringite, which affects strength stability at long-term curing, was detected at about 8 % at the initial curing age but increased to over 40 % at the long-term curing age, indicating that ITB grout has excellent long-term durability. SEM-EDX tests revealed the growth of C-S-H gel and a significant amount of Ettringite compared to the LW method, confirming the favorable initial gelling action of ITB grout. The leaching tests showed no detection of harmful substances such as lead, cadmium, and hexavalent chromium, and the ecotoxicity tests indicated no mortality in test fish, with a pH of approximately 8.5. Based on these results, it is concluded that ITB grout is a method advantageous in terms of long-term durability and environmental performance compared to the LW method, making it suitable for use as a backfill material in shield TBM applications. |