| Vacuum preloading method has obvious advantages in improving bearing capacityand deformation characteristics of soft clay foundation. Currently, study mainlyfocused on reinforced area soil, while deformation of un-reinforced area soil isbringing us serious engineering accident occasionally, such as house-tilt,pipeline-rupture, embankment-destruction and so on. Therefore it has practicalsignificance to study deformation mechanism and influence range of un-reinforcedarea soil. With help of theoretical methods and ABAQUS numerical simulation, adetailed analysis is conducted in un-reinforced area soil deformation laws withvacuum preloading, getting the main conclusions as follows:(1) Lateral deformation of un-reinforced area comes from the role of negativepressure seepage field, reinforced area horizontal contraction and lateral unloading,while the first one plays the most critical role.(2) Based on Barron consolidation equation, an analytical solution for finalconsolidation is developed with consideration of lateral and vertical seepage.According to empirical relationship of soil displacements, maximum horizontaldisplacement and overall distribution can be estimated from final analytical solution.(3) In the vacuum preloading process, surface subsidence is the maximum valueand has a rapid growth in initial period. Horizontal displacement and pore pressurehas similar variation with time lag.(4) According to numerical simulation results, reducing the length of plasticdrain board can significantly improve the reinforcement effect of shallow soil. Shotboard, long-short board, graded board and other construction forms can be putforward to improve soil reinforcement effect.(5) Setting a row of piles can significantly reduce the maximum horizontaldisplacement in non-reinforced area. Optimal location of piles is within4m toreinforcement boundary, where it achieve the desired effect that gripe maximumhorizontal displacement in non-reinforced area. |
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