Prediction Of Ground Settlement By Peck-Fujita And Numerical Methods

Prediction of ground surface settlement in soft ground has significant importance because of dangerous effects of settlement on existing surface and subsurface structures. For metro project of Tabriz city, excavation of two parallel tunnels with external diameter of 6.88 m by the shield tunneling method is considered. These tunnels are located in cohesionless soils below the ground water table. In this paper, ground surface settlement troughs caused by construction of these twin tunnels were predicted by Peck-Fujita empirical method for single tunnel and were generalized to twin tunnel case by use of superposition principle. The distance between centerlines of tunnels was increased from 13.6 m to 28.6 m in six steps. Then these troughs were comparized with the results obtained from PLAXIS software in drained conditions. Good agreement between these two methods was representative of accuracy of proposed procedure for prediction of ground surface settlement trough in cohesionless soils.