Improvement of Organic Soil Using Jet Grout Columns

9th International Black Sea Coastline Countries Scientific Research Conference, Ankara, Türkiye, 10 - 11 Ağustos 2023, ss.176-183

The characteristics of peaty soils that are widely recognized include their high

compressibility and poor shear strength. The construction of any structure on these

cohesive soils requires careful consideration of stability and settlement, giving rise to

significant challenges. Geotechnical engineers have developed various strategies to

address these challenges in the past decade. These solutions encompass applications of

some remedial techniques such as vertical drains, preloading techniques, geosynthetics,

concrete piles, deep mixing columns, stone columns, and jet grout columns (JGC).

Contemporary

advancements in construction technology have led to significant progress

in enhancing the quality of soft soil. One such technique that has gained significant

popularity is jet grouting, which proves to be economically viable, technically efficient,

and widely adopted for reinforcing peaty soil. The structures constructed within the

boundaries of Kayseri Free Zone have encountered settlement issues attributed to the

presence of peat and organic soil layers. This study aims to examine the impact of

spacing between JGCs (Jet grout columns) on the performance of organic soil. The

researchers designed a square steel box to conduct undisturbed soil sampling and model

tests. The settlement of peat improved with end-bearing JGC was assessed using finite

element method (FEM), employing PLAXIS 3D software. A rigid-square plate was

subjected to vertical stress to simulate a single footing. The Mohr-Coulomb model was

applied in the analysis of JGC, whereas the soft soil model was employed to capture the

behavior of peat in the finite element simulation. The study's findings illustrated that the

improved soil showed a significant increase in bearing capacity, ranging from 3.5 to 4.0

times greater than its initial state. Furthermore, the settlement values obtained from the

software simulations were comparable to those observed in physical model tests.