Ph.D. Tezi Görüntüleme

Student: Mustafa VEKLİ
Supervisor: Prof. Dr. Mustafa AYTEKİN
Department: İnşaat Mühendisliği
Institution: Graduate School of Natural and Applied Sciences
University: Karadeniz Technical University, Turkey
Level: Ph.D.
Acceptance Date: 25/6/2009
Number of Pages: 197
Registration Number: Di696

      Use of stone columns in soft soils has emerged as a major ground improvement technique for the last three decades.

In this study, an investigation has been performed to see effect of stone columns placed in a slope in soft soil with a ratio of distance between stone column axis to their diameters (s/D) on slope stability, ultimate bearing capacity, settlement of the foundation rested on top of slope on a small scale laboratory model. Firstly, ultimate bearing capacity and settlement properties of soil were determined with no stone columns. Then, some values of soil were determined after the installation of stone columns with various ratios of s/D (distances between stone column centers/columns diameters). The ratios of (s/D) were 2, 3, 3.5 and 4. Tests carried out in the laboratory were simulated and numerically analyzed using Plaxis computer code which is software uses finite elements. From results of the tests and numerical analyses, bearing capacities of structure constructed on the soft soil with slope were increased; settlements were decreased after improvement with stone column. Furthermore, some increment at the bearing capacity, and some reduction at the settlements were occurred with the reduction of s/D ratios.

      To investigate effect of stone columns on the slope stability, a parametric study was carried out examining cases with single layer, double layer and presence of water in the reservoir side of the slope. Analyses in the study were performed by Plaxis for various slope angles, ratios of c/(H) and ratios of s/D. From the analyses performed, it was found that the stone columns redoubled 1.181.62 fold stability of slope as relative effect of different parameters. Factor of safety and improvement factor of safety (GİF) of slopes improved with stone column are given in Tables and Figures. It is thought of that tables and figures given in this study are helpful for engineers at the applications where required promptly to be begun and to be completed.

      Key Words: Stone column, Slope stability, Soil improvement, Finite elements, Laboratory model