Abstract
In this era of modern time where due to rapid growth in population, expanding industrialization etc., within the same limited resources including the land resources enforces the mankind to use the land resources in an economical manner, leading to demand of use of areas having soft soils, dumping places, wetlands, landfill sites (after closure) and even to go for vertical expansion rather than horizontal in terms of multistory buildings, tall structures etc., leading to imposition of huge loads, which cannot be supported by the existing soil at such places. So as a ground improvement measure, the present paper focuses on introducing stiffening effect in the top region of the granular pile. Stiffening means replacing the conventional material of the granular pile in the top region up to a certain depth that is why calling it partial stiffening, by a material having better mechanical properties and thus not only providing the solution to the problem of bulging but also increasing the load-bearing capacity by reducing the settlements. Analysis of a partially stiffened group of two granular floating and end bearing granular piles has been numerically assessed and presented here. Normalized parameters like shear stress distribution along soil–granular pile interface, axial load distribution along soil–granular pile interface and percentage load transferred to the base are evaluated. The shear stresses are found to reduce at the top of GP in a group of two GPs and are transferred toward the base of the GP.
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Abbreviations
- GP:
-
Granular pile
- L :
-
Length of granular pile
- n :
-
Total number of elements of GP
- d :
-
Diameter of granular pile
- L/d :
-
Relative length of GP
- P :
-
Load on each granular pile of two pile groups
- E gp :
-
Deformation modulus of un-stiffened portion of GP
- E b :
-
Deformation modulus of base stratum
- E s :
-
Deformation modulus of soil
- νs, νgp and νb:
-
Poisson’s ratio of soil, GP and base stratum, respectively
- Kgp = (Egp/Es):
-
Relative stiffness of granular pile
- p b :
-
Pile base pressure
- z :
-
Depth of granular pile section taken from the top of granular pile
- z* (= z/L):
-
Normalized depth of GP
- s :
-
Spacing between center to center of the piles
- s/d:
-
Normalized spacing center to center between piles
- I sp :
-
Settlement influence factor at top
- τ :
-
Shear stress
- \(\tau_{{2{\text{F}}}}^{*} = \tau \left( {\pi dL} \right)/P\) :
-
Normalized shear stresses at various nodes of floating GP
- \(\tau_{{2{\text{E}}}}^{*} = \tau \left( {\pi dL} \right)/P\) :
-
Normalized shear stresses at various nodes of end bearing GP
- L s :
-
Length of the pile stiffened from the top of the pile
- η = Ls/L:
-
Relative length of stiffening
- χ :
-
Relative stiffness of granular pile
- ρ p :
-
Normalized displacement of nodes of GP along its length
- ρ s :
-
Normalized vertical displacement of soil
- S s :
-
Vertical soil displacement
- P*:
-
Normalized axial load = Pz/P
- P z :
-
Axial load at the depth z
- (Pb/P)2F × 100:
-
Percentage load transferred to the base in a group of two partially stiffened floating GPs
- (Pb/P)2E × 100:
-
Percentage load transferred to the base in a group of two partially stiffened end bearing GPs
- [IFs]:
-
A square matrix for soil displacement influence coefficient
- \(\left[ {_{1} {\text{IF}}^{s} } \right]\,{\text{and}}\,[_{2} {\text{IF}}^{s} ]\) :
-
A square matrix for soil displacement influence coefficient for self and adjacent GP, respectively
- εv and σv:
-
Axial strain and stress on an element, respectively
- Pit and Pib:
-
Axial force on top and bottom of an element, respectively
- σit and σib:
-
Axial stresses on top and bottom of an element, respectively
- σvi:
-
Average axial stress on the element
- MA, MB, MD:
-
Square matrices
- \(_{1} {\text{IF}}^{\text{sp}} \,{\text{and}}\,_{2} {\text{IF}}^{\text{sp}}\) :
-
Square matrices
- \(_{1} {\text{IF}}^{\text{spim}} \,{\text{and}}\,_{2} {\text{IF}}^{\text{spim}}\) :
-
Square matrices
- εvj and εvi:
-
Axial strain of jth and ith element, respectively
- εb:
-
Axial strain of the base of the GP
- Δ1 Δ2:
-
Square matrix
- κ :
-
A non-dimensional parameter for consideration of base stratum
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Sharma, J.K., Garg, V. (2020). Effect of Stiffening on Stress Distribution Along Soil–Granular Pile Interface. In: Latha Gali, M., P., R.R. (eds) Geotechnical Characterization and Modelling. Lecture Notes in Civil Engineering, vol 85. Springer, Singapore. https://doi.org/10.1007/978-981-15-6086-6_49
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DOI: https://doi.org/10.1007/978-981-15-6086-6_49
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