OJCE  Vol.4 No.1 , March 2014
Experimental Study of Dynamic Characteristics on Composite Foundation with CFG Long Pile and Rammed Cement-Soil Short Pile
ABSTRACT

Based on the idea of optimization design of pile type, the two kinds of the typical pile type are selected, which containing flexibility pile (e.g. rammed cement-soil pile is for short RCSP), and rigid pile (e.g. cement-flyash-gravel pile is for short CFGP). The three kinds of the composite foundation are designed, which are CFGP, CFG long pile and CFG short pile (for short CFGLP-CFGSP), CFG long-short pile and rammed cement-soil short pile (for short CFGLP-RCSSP). Natural earthquake is simulated by using the engineering blasting; the dynamic characteristics and dynamic response of the composite foundation are studied through field test. CFGLP-RCSSP is closed to linear relation. The bearing capacity of the four composite foundation of the CFGP, CFGLP-CFGSP, and CFGLP-RCSSP in the site are 225 kPa, 179 kPa, and 197 kPa, separately increases 150%, 98.8% and 119% compared to the natural foundation. The vibration main frequency is mainly depended on properties of foundation soil and piles between vibration source and measuring point, pilling load value. Horizontal vibration main frequency greater than the vertical vibration main frequency and the vertical vibration main frequency close to the first-order natural frequency of composite foundation. With the pilling load increasing, the CFGLP-RCSSP pile composite foundation combined frequency decreased. Under the same blast energy, the acceleration peak on the CFG pile composite foundation is less than CFGLP-CFGSP the corresponding values, as the load increases, the peak acceleration gently. CFG pile composite foundation is favorable on seismic. The distribution of peak acceleration is consistent within 4 m from pile top in the CFGLP_RCSSP composite foundation. The maximum of the horizontal acceleration peak along the pile body occurs at a distance of pile top 4 m or the pile top, and that of vertical acceleration peak occurred at a pile top.


Cite this paper
Ding, J. , Cao, Y. , Wang, W. , Zhao, T. and Feng, J. (2014) Experimental Study of Dynamic Characteristics on Composite Foundation with CFG Long Pile and Rammed Cement-Soil Short Pile. Open Journal of Civil Engineering, 4, 1-12. doi: 10.4236/ojce.2014.41001.
References
[1]   (2002) GB50007-2002 Code for Design of Building Foundation(s). China Architecture Industry Press, Beijing.

[2]   Yoshio, S. (1983) Deep Mixing Chemical Method Using Cement as Hardening Agent. Symposium on Soil and Rock Improvement Techniques, Bangkok, 34-37.

[3]   Horii, N., Toyosawa, Y., Tamate, S. and Hashizume, H. (1998) Stability of Composite Ground Improved by Deep Mixing Method. Proceedings of 2nd International Conference on Ground Improvement Techniques, Singapore, 193-198.

[4]   Zheng, G. and Jiang, X.L. (1999) Research on the Bearing Capacity of Cement Treated Composite Foundation. Rock and Soil Mechanics, 3, 46-50.

[5]   Ma, H.L. (2003) Quantitative Analyses of the Influence of Pile Length and Other Factors on Capability and Modul of Cement Stabilized Soil Composite Foundation. Chinese Journal of Geotechnical Engineering, 11, 720-723.

[6]   Fu, J.H. and Song, E.X. (2000) Analysis of Rigid Pile Composite Foundation’s Working Performance. Rock and Soil Mechanics, 21, 335-339.

[7]   Wang, M.-S., Wang, G.-C., Yan, X.-F., et al. (2005) In-Situ Tests on Bearing Behavior of Multi-Type-Pile Composite Subgrade. Chinese Journal of Geotechnical Engineering, 27, 1142-1145.

[8]   Yan, M.L., Wang, M.S., Yan, X.F. and Zhang, D.G. (2003) Study on the Calculation Method of Multi-Type-Pile Composite Foundation. Chinese Journal of Geotechnical Engineering, 25, 352-355.

[9]   Ding, J.H. (2007) Reliability Analysis on the Bearing Capacity of Composite Foundation with Multi-Type Compound Piles. Engineering Mechanics, 25, 168-172.

[10]   Ding, J.H., Liu, F.R. and Du, E.X. (2008) Dynamic Characteristic Analysis on Composite Foundation with Soil-Cement Piles and CFG Piles. Fly-Ash Comprehensive Utilization, 6, 37-40.

[11]   Wang, W.Y., Zhao, T. and Meng, Y.J. (2012) The Numerical Analysis on Dynamic Characteristics of CFG Pile Composite Foundation under Blasting. Engineering Mechanics, 29, 150-155.

[12]   Wang, W.Y., Zhao, T. and Ding, J.H. (2011) Effects on Dynamic Characteristics and Response of Rammed Soil-Cement Pile Composite Foundation. Engineering Mechanics, 28, 187-191.

[13]   Wang, W.Y., Zhao, T. and Ding, J.H. (2010) Influence Factors of Dynamic Characteristics and Response of CFG Pile Composite Foundation. Chinese Journal of Geotechnical Engineering, S2, 115-118.

[14]   Zhao, T., Yang, C.M. and Wang, W.Y. (2010) The Dynamic Test Research on CFG Pile Composite Foundation under Blasting. Journal of Highway and Transportation Research and Development (Applied Technique), 7, 121-122.

[15]   Ding, J.H., Wang, W.Y., Zhao, T., et al. (2013) The Dynamic Characteristic Experimental Method on the Composite Foundation with Rigid-Flexible Compound Piles. Open Journal of Civil Engineering, 3, 94-98.
http://dx.doi.org/10.4236/ojce.2013.32010

 
 
Top