Numerical Analysis of Raft Foundation on Marine Clay Ground with Consideration of The Groundwater Level Variations

The research’s objectives measure the vertical displacement (or settlement) of the marine clay ground under the Raft foundation as the groundwater levels (GWL) change at different depths. The experimental method with the Vietnam Standards (TCVN) and simulation method by the PLAXIS 3D software (or Finite element method) is done to determine the ground settlement. The study results describe the maximum settlement obtained at 20.77 cm at 22.3 m of the GWL depths with a loading is 800 kN/m ² . Moreover, the Total deformation Modulus K _deformation of 44.38 kN/m ² with the Cohesion force K _cohesion of 40.2 kN/m ² , and Young elastic Modulus, K _Yeelastic of 200.78x10 ² kN/m ² from 15.3m to 19.5m of GWL depths; whereas the Shear resistance K _{shear resistance} obtains 124.1 kN/m ² with loading 200 (kN/m ² ) according to vertical displacement K _dis of 0.052 cm at 14.8 m depth. In comparison with simulated results indicate the maximum settlement is 150.7 cm with Cohesion force C _simu of 32.2 kN/m ² , Young modulus E _simu of 141.2 x10 ² kN/m ² where the active and passive pore water pressures obtain 227 kN/m ² at 7.3 m of depth with a settlement K _simudis of 25.180 cm. In conclusion, these results supply useful references to Geology and Civil engineering in the future.