Behavior of geotextile-reinforced embankment on soft ground | |
| Author | Pham Van Long |
| Call Number | AIT DISS. no. GE-96-01 |
| Subject(s) | Shear strength of soils--Testing Strains and stresses |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. GE-96-01 |
| Abstract | This study deals with the behavior of a geotextile reinforced embankment on soft ground which focused on following aspects: i) the interaction parameters between soil and geotextile reinforcement, ii) the localized mobilization of geotextile reinforcement force associated with slip failure, iii) the performance behavior of geotextile-reinforced embankment on soft Bangkok clays, and iv) the closed-form solution for rotational stability analysis of reinforced-embankment on soft foundation. Large direct shear tests have been conducted to investigate the shear resistance at the soil-geotextile interface. Back-analyses of the test data using finite element method (FEM) have been carried out for validation of the deformation parameters of backfill soil and soil-geotextile interface that cannot be determined directly from direct shear tests. A new method considering the non-uniform distribution of shear stresses along the reinforcement, the softening behavior at the interface, and the confinement-dependent behavior of geotextile stiffness has been proposed in this study. The purpose of this relates to the soil-geotextile interaction behavior from pullout tests, including the local shear stress-shear displacement at the pullout interface and the in-soil tension-strain of the geotextile reinforcement. Moreover, an extrapolation scheme for eliminating the slippage at the clamped end has been provided. Large direct shear tests with inclined geotextile reinforcement together with the finite element modelling have been carried out to study the localized mobilization of geotextile reinforcement forces in the vicinity of the slip surface. The localized strain in geotextile reinforcement associated with slip failure has been found to be a function of the in-soil stiffness and the corresponding inclination factor of the reinforcement. The results obtained herein can be used to estimate the limiting strain together with the orientation of the reinforcement at the onset of slip failure. The validation of this finding has been verified by comparing the results of back-analyses and the measured data from various test embankments. The performance behavior of a geotextile-reinforced embankment on soft Bangkok clay has been evaluated based on the interpretation of the test embankment data, the theoretical analyses using both finite element method (FEM) and conventional limit equilibrium method (LEM). Extensive parametric studies have also been performed in order to compare the results of stability analyses obtained by FEM and LEM and to validate the assumptions related to the magnitude and orientations of the reinforcement force used in circular slip analysis. Both the test embankments data and the results of theoretical analyses consistently suggested the two-step failure mechanism of high-strength geotextile reinforced embankments on a soft foundation. The method for estimating the limiting strain and the orientation of geotextile reinforcement corresponding to this failure mechanism has been given. The solutions for rotational stability analysis have been derived for the general case of an embankment on soft ground having a dry or wet tensile crack, counterweight berms, distributed load on the embankment crest, and different effects and directions of the reinforcement force. The solutions are presented in the form of simple equations that can be used conveniently in practical designs with a few hand calculation. Finally, the suggestions for improved design method considering the compatible deformations between soil and geotextile reinforcement have been made. |
| Year | 1997 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. GE-96-01 |
| Type | Dissertation |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical Engineering (GE) |
| Chairperson(s) | Bergado, Dennes T.; |
| Examination Committee(s) | Balasubramaniam, A.S.;Noppadol Phien-Wej;Wijeyewickrema, Anil C.;McGown, Alan; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 1997 |