Department of Civil Engineering LOAD SETTLEMENT BEHAVIOUR OF JUTE GEOTEXTILE REINFORCED SUBGRADE OF RURAL ROAD USING ABAQUS Sudip K. Roy Ambarish Ghosh Ashis Kumar Bera Sandip Chakraborty Department of Civil Engineering Bengal Engineering and Science University, Shibpur Howrah – 711103 June, 2013

Why Numerical Analysis?

SELECTION OF NUMERICAL TOOL

LITERATURE REVIEW Researchers Research Area/ Findings S. Pirabarooban, M. Zaman, R. A. Tarefder. (2003) FEM results show that the ABAQUS-based model can adequately account for cyclic loading and other factors and, as such, it can be used effectively to evaluate the rutting potential of in-service pavement. K. Nesnas, M. Nunn. (2004) A response model (3D) is generated in ABAQUS to predict top down cracking R. Zafar, W. Nassar and A. Elbella. (2005) In this study the finite element software ABAQUS is used to study stress redistribution due to the presence of earth pressure cell (vertical stress-measuring instrument) in the pavement layers W.G. Buttlar, G. H. Paulino, and S. H.Song. (2006) Numerical examples and an implementation using the user material subroutine UMAT of the finite element software ABAQUS are also provided to illustrate the benefits of using graded elements in pavement analysis.

LITERATURE REVIEW Researchers Research Area/ Findings Tabakovic, Amir; McNally, Ciaran; Sorelli, L. G.; Gibney, Amanda; Gilchrist, M. D. (2006) A damage mechanics model has been developed in order to compare the behaviour of RAP (Recycled Asphalt Pavement), The damage model was implemented within the ABAQUS finite element code using a UMAT subroutine Grace G. Abou-Jaoude, Ziad G. Ghauch A 3D Finite Element model of the pavement involving a linear viscoelastic constitutive model for HMA materials and non-uniform tire contact stresses is developed using ABAQUS 6.11 to investigate the effectiveness of several design strategies involved in long-life, perpetual pavement design A.M.Khaki, E. Azadravesh. (2010) A 3D FE model is generated by ABAQUS for evaluating the effects of joint opening on load transfer efficiency in concrete pavements Rahman M.T , Mahmud K, Ahsan S. (2011) In this study, a 3D finite element model of flexible pavement is developed using ABAQUS for better prediction of mechanical behaviour and pavement performance subjected to various traffic factors.

LITERATURE REVIEW Researchers Research Area/Findings B. Sukumaran, V. Kyatham, A. Shah, D.Sheth. (2004) The stress-strain response of the various soils is simulated using an elasto-plastic model and von Mises strength criteria available in finite element code ABAQUS. The empirical relationship between CBR and resilient modulus is investigated based on the results obtained from the three dimensional finite element analyses. Gholam Ali Shafabakhsh, Abbas Akbari. (2013) 3D modelling with help of finite element computer code ABAQUS has been used to determine the role of different parameters of passenger, commercial and military airplane’s main gear s which cause the major failures to the rigid runway pavements. Gholam Ali Shafabakhsh, Mana Motamedi, Afshin Family. (2013) This research, at first, tends to investigate influence of changing asphalt pavement thickness in vertical strain using finite element software (ABAQUS) and finally, the results related to the finite element, were compared with experimental data.

ABAQUS A Finite element Software Robustness in numerical solution strategy for soil nonlinearity, Capable of solving most geotechnical problems, Involving two- and three-dimensional configurations, Soil and structural elements, Wide range of material property can be used Total and effective stress analysis, Consolidation analysis, Seepage analysis, Static and dynamic analysis, etc.

ABAQUS Huang et al. (2006) carried out finite element analysis to study the consolidation behaviour of an embankment on soft ground. Hadi and Bodhinayake (2003) carried out finite element analysis of road emabankment in ABAQUS. Kuo and Chou (2004) developed and analyzed a three dimensional model for flexible pavement using ABAQUS software

Jute Geotextile Application Bera et al. ( 2009 ) carried out series of unconfined compression strength tests of fly ash reinforced with jute geotextile. Chattopadhyay and Chakraborty ( 2009 ) studied the application of JGT as facilitator in drainage. Sahu et al. ( 2004 ) carried out model footing test to determine the behaviour of JGT reinforced soil bed and to asses aging effect of soil along with degradation of JGT with time

Fig.1 Unreinforced Road Section Rajar hat Test Track A trial stretch road section: Data Given: CBR=3% (assumed) ESAL=60000 to 100000 Unreinforced Road Section As per IRC: SP: 72-2007, Subgrade Strength as per CBR=3%; it is Poor. Premix Carpet = 20 mm WBM (Grade-II) = 75 mm WBM (Grade-III) = 100 mm GSB(Grade-II) =150 mm Fig.1 Unreinforced Road Section

Rajar hat Test Track Fig.2 Unreinforced Road Section ( Reduced GSB )

Rajar hat Test Track Fig 3.Reinforced Road Section with JGT (20kN/m)

Rajar hat Test Track Fig 4.Reinforced Road Section JGT (25kN/m)

Rajar hat Test Track Fig 5.Reinforced Road Section with Geosynthetics

Unreinforced road section Problem Description Unreinforced road section Unreinforced Road Section ( Reduced GSB ) Reinforced Road Section with JGT (20kN/m)

Fig.6 Unreinforced road section (UR GSB 100 ) Geometry of the Model Fig.6 Unreinforced road section (UR GSB 100 )

Fig.7Unreinforced road section (UR GSB 175 ) Geometry of the Model Fig.7Unreinforced road section (UR GSB 175 )

Fig.8 JGT ( 20kN/M ) Reinforced road section (GSB 100 ) Geometry of the Model Fig.8 JGT ( 20kN/M ) Reinforced road section (GSB 100 )

Material property Material Model used Density (kN/m3) Elastic Modulus (MPa) Poisson’s ratio Friction angle (Degree) Dilation angle Cohesion (kPa) WBM Linear Elastic 15.2 19 0.4 NA GSB 14.5 20 Sand 15.5 15 0.3 JGT 80 Subgrade Mohr-Coulomb model 13.95 10 2 30 Existing soil layer Mohr- Coulomb model 14.0 12

LOAD Static Load & Boundary Condition Fig. 9 Load and Boundary condition applied to the model (Reinforced section, JGT100)

Cyclic load and Time Stepping

INTERACTION

Meshing Criteria ( a ) UR GSB 100 ( b )REINFORCED Fig.10 Mesh model

Results and Discussions Deformed Shape Fig.11 Deformed shape for UR GSB 100

Results and Discussions Deformed Shape Fig.12Deformed shape for UR GSB 175

Results and Discussions Deformed Shape Fig.13 Deformed shape for JGT Reinforced Section

Results and Discussions Deformed Shape JGT Fig.14 Deformed shape for JGT Reinforced Section

Results and Discussions Deformed Shape Fig.15 Deformed and Undeformed shape for JGT Reinforced Section

Results and Discussions Fig.16 Tensile stress ( ) & Compressive stress ( )

Results and Discussions Fig.17 Typical Load settlement plot at subgrade unreinforced ( UR GSB 100 ) road section ( by using cyclic loading)

Results and Discussions Fig.18 Typical Load settlement plot at subgrade Reinforced road section ( Cyclic loading )

Results and Discussions Effect of JGT on rut depth of road section Fig.19Load (Static) vs. Rut depth (mm)

Results and Discussions Effect of JGT on rut depth of road section Fig.20 Rut depth (mm) for the three models ( Subgrade top )

Results and Discussions Effect of JGT on rut depth of road section Fig.21 Comparison between rut depth for unreinforced ( URGSB 100 ) and reinforced model after 8 hours vehicle movement at an interval of 45 second

Results and discussions Effect of JGT on stresses developed of Subgrade top

Conclusions With the introduction of JGT reinforcement in between subgrade and granular base layer the values of rut depth decreases significantly. Cyclic loading developed larger rut depth compared to static loading irrespective of types of road section. Stress developed on the subgrade top in case of JGT reinforced road section is much lesser than road section without reinforcement. ABAQUS software can effectively analyse the any types of road sections ( Reinforced & Unreinforced ). By using this software researcher may observe any types of load ( compressive/ tensile ), directions, deformations at any point.

References Bera, A.K., Chandra, S.N., and Ghosh, A. ( 2009 ) “ Unconfined compressive strength of fly ash reinforced with jute geotextiles”, Geotextiles and Geomembranes, 27 ( 5 ), pp. 391-398. Bhasi.A. Rajagopal, K.(2010) “Finite Element Analysis of Geosynthetic reinforced pile supported embankments.” SIMULIA Customer Conference. Chattopadhyay, B.C., and Chakraborty, S. ( 2009 ) “ Application of jute geotextiles as facilitator in drainage”, Geotextiles and Geomembranes, 27 ( 2 ), pp. 156-161. Hadi,N.S. and Mukammad. Bodhinayake, B.C. (2003) “Non-linear finite element analysis of flexible pavements” Elsevier, Advances in Engineering Software , 34, pp.657–662. Helwany, S. Dyer, J. and Leidy, J. (1998) “Finite element analysis of flexible pavement.” , Journal of transportation engineering, September/October, pp.491- 499. Helwany,S.(2007) “Applied soil mechanics with Abaqus application”, John Wiley & Sons. Kuo, C.M, Chou, F.J. (2004). “Development of 3-D Finite Element model for Flexible Pavements” Journal of the Chinese Institute of Engineers, 27, ( 5 ), 707-717. Sahu, R.B., Hazra, A.K.and Som, N. ( 2004 ) “ Behaviour of geojute reinforced soil bed under repetitive loading- a model study” BCC iInternational Conference on Geosynthetics and Geoenvironment Engineering, Bombay

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