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A Numerical Approach for Determination of Soil Parameters by Pressuremeter Test

Keshmiri, Ehsan | 2015

1986 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 47327 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Ahmadi, Mohammad Mehdi
  7. Abstract:
  8. In-situ tests are strongly recommended in site investigations, since laboratory studies are not sufficient for precise determination of soil parameters. Effects of soil disturbance on laboratory studies questions the validation of obtained soil parameters. In the in-situ tests, soil experience less disturbance and these tests are conducted in stress levels resembling to soil initial horizontal and vertical stresses. Also more volume of soil is tested by in-situ tests in comparison to laboratory studies. Pressuremeter instrument was invented by Menard (1954). In this test, a flexible cylinder is expanded in the cavity under fluid pressure and the volume and stress changes of the cavity are measured continuously. Results of this test are applicable for estimation of mechanical soil properties. In this study, a literature review is done on the theoretical and empirical methods of interpretation of pressuremeter test.Then, numerical modelling of pressuremeter test in FLAC software is detailed. Effects of boundary conditions and constitutive models on cavity pressure expansion curve are assessed. After that, different theories of cavity expansion are compared to numerical modelling results and the efficiency of each method in determination of soil parameters is evaluated. More than 5000 numerical analyses of cavity expansion was performed in sand and by the aid of genetic algorithm, a relationship was proposed for estimation of sand parameters, particularly in-situ horizontal stress
  9. Keywords:
  10. Numerical Modeling ; Genetic Algorithm ; Pressuremeter Test ; Clay Parameters ; Sand Parameters

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