# Evaluate the bearing capacity of CFG pile by numerical method

• N B Umravia
• C.H. Solanki Professor, Applied Mechanics Department, Sardar Vallbhbhai National Institute of Technology, Surat
Keywords: Numerical analysis; Soft soils; CFG (Cement-Fly Ash Gravel) Pile; PLAXIS-2D; DM Deep mixing Column, Stress Distribution.

### Abstract

Numerical modeling by finite element method or by finite difference method is becoming popular. The numerical or statistical model cannot predict the actual in-situ behavior of soil under loading conditions. It is the accuracy of the mathematical tool, which plays a significant role in predicting the behavior of the model and helps in an experimental model. Geotechnical engineers face many difficult challenges when design structure over soft soils. These include lateral displacement and movement, potential bearing failure, Differential settlement, local and global instability. Cement fly-Ash Grave (CFG) piles with composite foundation are widely used for ground improvement technique. It would be help to reduce the Geotechnical difficult problem of structure over soft soil.  This paper aim is to the parametric study of CFG pile using the FEM method. This numerical analysis had carried out using FEM software PLAXIS 2D. In this paper study two dimensions axisymmetric model validated by Finite element approach (FE) using with different Diameters of a pile, length variation, strength of pile, Cohesive of Soft Soil. discussed were on based of FE models results; the pile stress under prescribed settlement  as well soil stress distribution under load and pile-soil stress concentration ratio of the CFG Piles for evaluate bearing capacity under the soft soil. The results indicate that the soil pressure distribution and stress on the pile is relatively to compare the load-deformation behavior with the model tests.

### References

Abusharar, S.W., Zheng, J.J., Chen, B.G. and Yin, J.H., 2009. A simplified method for analysis of a piled embankment reinforced with geosynthetics. Geotextiles and Geomembranes, 27(1), pp.39-52. 1
Agaiby, S.W. and Jones, C.J., 1995. Design of reinforced fill systems over voids. Canadian geotechnical journal, 32(6), pp.939-945. 8
Almeida e Sousa J. Tunnels in soils: “Behaviour and numeric modelling. Ph.D. thesis, University of Coimbra; 1998 [in Portuguese].
Balasubramaniam, A.S., Cai, H., Zhu, D., Surarak, C. and Oh, E.Y.N., 2010. Settlement of embankments in soft soils. Geotechnical Engineering, 41(1), p.61. 23
Chen, Q.N., Zhao, M.H., Zhou, G.H. and Zhang, Z.H., 2008. Bearing capacity and mechanical behavior of CFG pile composite foundation. Journal of Central South University of Technology, 15, pp.45-49.4
Chi, Y.J., Song, E.X., Jin, H. and GAO, W.X., 2003. Experimental study on stress distribution of composite foundation with rigid piles. ROCK AND SOIL MECHANICS-WUHAN-, 24(3; ISSU 84), pp.339-343.
Deng, L., 2014. CFG Pile Based Soft Foundation Treatment. In Applied Mechanics and Materials (Vol. 484, pp. 790-795). Trans Tech Publications.
Lijun Wu (2018) “Performance of Geosynthetic-Reinforced and Cement-Fly Ash-Gravel Pile-Supported Embankments over Completely Decomposed Granite Soil: A Case Study” Hindawi Advances in Materials Science and Engineering Volume, pp 1- 11.
Li, N., Han, X. (2001). Study on mechanism of cushion in composite pile foundation. China Civil Engineering Journal 34(2), 68–73
Pan, J., Liu, Z., Ji, J., Lu, Z., Li, T. (2001). The test research about the loading behavior of CFG piles composite foundation. Geol. Prospect. 4, 28
Vishal V. Pagar and Vijaykumar Sharma (2018), “Review of Existing Design Methods for CFG (Cement-Fly Ash- Gravel) Pile Supported Composite Foundation Embankment” IJETSR Volume 5, Issue 3, PP 799- 806
Venda Oliveira PJ. Embankments on soft clays – numeric analysis. Ph.D. thesis, University of Coimbra; 2000 [in Portuguese].
Venda Oliveira PJ, Correia AAS, Lemos LLJ. Numerical prediction of creep of an embankment over deep soil mixing columns. In: International symposium of deep mixing & admixture stabilization, Okinawa, Japan; 2009.
Venda Oliveira PJ, Lemos LJL. Numerical analysis of an embankment on soft soils considering large displacements. Comput Geotech 2011;38:88–93.
Venda Oliveira PJ, Lemos LJL, Coelho PALP. Behavior of an atypical embankment on soft soil: field observations and numerical simulation. J Geotech Geoenviron Eng (ASCE) 2010;136(1):35–47.
Yan Jiang; Gang Zheng; and Jie Han, F.ASCE (2017) “Numerical Evaluation of Consolidation of Soft Foundations Improved by Sand–Deep-Mixed Composite Columns International Journal of Geomechanics, © ASCE, PP 1 -12.
Zhang, B., Cui, S., Liu, Z., and Feng, F. (2016), “Field Tests of Cement Fly-Ash Steel-Slag Pile Composite Foundation,” Journal of Testing and Evaluation, PP 1-14.
Published
2018-10-05
Section
Articles