IMPROVING OF SOFT CLAY SOIL AROUND TUNNEL OPENNING USING STONE COLUMNS AND ITS EFFECT ON THE BEHAVIOR OF TUNNEL LINING | ||||
| JES. Journal of Engineering Sciences | ||||
| Article 2, Volume 39, No 5, September and October 2011, Page 947-963 PDF (634.51 K) | ||||
| Document Type: Research Paper | ||||
| DOI: 10.21608/jesaun.2011.129375 | ||||
 View on SCiNiTO | ||||
| Author | ||||
| Mostafa Abdou Abd El-Naiem | ||||
| Civil Engineering Department, Assiut University, Assiut, Egypt | ||||
| Abstract | ||||
| The increasing demand for new infrastructure developments has recently led to an escalating trend to develop sites with inadequate ground conditions that were previously considered uneconomical to develop. These situations have posed challenged that geotechnical engineers are meeting by cultivating innovative techniques like stone columns to overcome soft clay soil conditions. Among the various methods for improving in situ ground conditions, stone columns are considered one of the most versatile and cost-effective ground improvement techniques. Stone columns reinforce cohesive soils and densify granular soils in order to increase bearing capacity and decrease total and differential settlement. The accuracy of the results obtained depends on the knowledge of the input data for the tunnel and the surrounding soil. Many geotechnical challenges are expected to occur related to soft clay soil stability and tunnel lining. One of these problems is expected to occur related to tunnel lining stability and surrounding soil is the high values of settlement due to compressibility of soft layer when it lies around or below tunnel lining. This present study aims to improve the behavior of tunnel lining and eliminate the effect of soft clay layer on this behavior by using vertical stone columns. This study is carried out by using Finite Element Method. The tunnel lining is meshed with two dimensional elements, called BEAM 6 element. The soil and stone columns are meshed with another two dimensional elements called LST, (Linearly Varying Strain Triangular Element). In this study, the main parameters were taken into consideration are the position and properties of stone columns. It can be concluded that using of stone columns in tunnel opening zone has strong effect on the improving behavior of tunnel lining. For application of this study, data of Cairo Metro Tunnel- Line 2, was chosen. The results of this study were compared with the initial values obtained from case of does not include stone columns. | ||||
| Keywords | ||||
| IMPROVE; SOFT CLAY; LAYERED SOIL; STONE COLUMNS; TUNNEL; FORCES; DEFORMATION; F.E.M | ||||
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