Abstract
The paper presents a model for the analysis of granular foundation beds reinforced with several geosynthetic layers. Such reinforced granular beds are often placed on soft soil strata for an efficient and economical transfer of superstructure load. The granular bed is modeled by the Pasternak shear layer and the geosynthetic reinforcement layers by stretched rough elastic membranes. The soft soil is represented by a series of nonlinear springs. The reinforcement has been considered to be extensible and it is assumed that the deformation at the interface of the reinforcements and soil are same. The nonlinear behavior of the granular bed and the soft soil is considered. Plane strain conditions are considered for the loading and reinforced foundation soil system. An iterative finite difference scheme is applied for obtaining the solution and results are presented in nondimensional form. The results from the proposed model are compared to the results obtained for multilayer inextensible geosynthetic reinforcement system. Significant reduction in the settlement has been observed when the number of reinforcement layer is increased. In case of inextensible reinforcements as the number of reinforcement layer is increased the settlement is decreased with a decreasing rate, but in case of extensible reinforcement the reduction rate is almost constant. Nonlinear behavior of the soft soil decreases as number of reinforcement layer is increased. The effect of the stiffness of the geosynthetic layer on the settlement response becomes insignificant for multilayer reinforced system, but the mobilized tension in the reinforcement layers increases as the stiffness of the geosynthetic layers increases.
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Abbreviations
- B :
-
half width of uniform surcharge load (m)
- E g :
-
tension modulus of the geosynthetic layers (N/m)
- E *g :
-
normalized E g (dimensionless)
- G j0 :
-
initial shear modulus of the granular fill layer 1, 2, 3, 4, respectively (N/m2)
- G * j0 :
-
normalized G j0 (dimensionless)
- H j :
-
thickness of the granular fill layer 1, 2, 3, 4, respectively (m)
- k s0 :
-
initial modulus of subgrade reaction for soft foundation soil (N/m3)
- L :
-
half width of geosynthetic-reinforced zone (m)
- N :
-
number of geosynthetic layer (dimensionless)
- q :
-
pressure intensity on the top granular layer (N/m2)
- q * :
-
normalized q (dimensionless)
- q s :
-
vertical reaction pressure of the soft foundation soil (N/m2)
- q *s :
-
normalized q s (dimensionless)
- q u :
-
ultimate bearing capacity of the soft soil (N/m2)
- q *u :
-
normalized q u (dimensionless)
- T j=1,2,3 :
-
mobilized tension in the top, middle and bottom geosynthetic layer, respectively (N/m)
- T * j=1,2,3 :
-
normalized T j=1,2,3 (dimensionless)
- T p :
-
pretension force applied to the geosynthetic layers (N/m)
- T *p :
-
normalized T p (dimensionless)
- w :
-
vertical displacement (m)
- W :
-
normalized w (dimensionless)
- x :
-
distance from centre of loading (m)
- X :
-
normalized x (dimensionless)
- θ:
-
slope of the membrane (degree)
- τ j=1,2,3,4 :
-
shear stresses in the granular layer 1, 2, 3, 4, respectively (N/m2)
- τ * j=1,2,3,4 :
-
normalized τ j=1,2,3 (dimensionless)
- τ uj=1,2,3,4 :
-
ultimate shear resistance of the granular layer 1, 2, 3, 4, respectively (N/m2)
- τ * uj=1,2,3,4 :
-
normalized τ uj=1,2,3,4 (dimensionless)
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Deb, K., Chandra, S. & Basudhar, P.K. Nonlinear analysis of multilayer extensible geosynthetic-reinforced granular bed on soft soil. Geotech Geol Eng 25, 11–23 (2007). https://doi.org/10.1007/s10706-006-0002-7
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DOI: https://doi.org/10.1007/s10706-006-0002-7