Soft Foundation Strengthening Effect and Structural Optimization of a New Cement Fly-ash and Gravel Pile-slab Structure


1 School of Civil Engineering, Hubei Polytechnic University, Hubei, China

2 Department of Civil and Earth Resources Engineering, Kyoto University, Kyoto, Japan


Reducing the settlements of soft foundation effectively is a critical problem of high-speed railway construction in China. The new CFG pile-slab structure composite foundation is a ground treatment technique which is applied on CFG pile foundation and pile-slab structure composite foundation. Based on the experience of constructing Beijing-Shanghai high-speed railway in China, the settlement-controlling effect, the settlement distribution laws and three key influence factors for structural form of new CFG pile-slab structural foundation are studied by using physical model tests and numerical simulations. The research results in this study indicate that the piles and soil bearing capacities of the new CFG pile-slab structure can be put into full play because of the “load distributing” function of slabs. The settlement reducing effect of the new CFG pile-slab structure is remarkable and can meet the requirements of high-speed railway construction. The affected area of engineering load has a depth over 18.75 m and horizontal length of 7.5 m nearing the embankment slope toe. The parametric study provides the optimalizing structural form for best settlement-controlling effect. The physical model test results show good concordance with the numerical simulation results. The combination of physical model tests and numerical simulations justifies the use of this model in geotechnical engineering practices.


1.     Zhan, Y.-x., Yao, H.-l. and Jiang, G.-l., "Design method of pile-slab structure roadbed of ballastless track on soil subgrade", Journal of Central South University,  Vol. 7, No. 20, (2013), 2072-2082.
2.     Abusharar, S.W., Zheng, J.-J. and Chen, B.-G., "Finite element modeling of the consolidation behavior of multi-column supported road embankment", Computers and Geotechnics,  Vol. 36, No. 4, (2009), 676-685.
3.     Chen, R., Chen, Y., Han, J. and Xu, Z., "A theoretical solution for pile-supported embankments on soft soils under one-dimensional compression", Canadian Geotechnical Journal,  Vol. 45, No. 5, (2008), 611-623.
4.     Okyay, U., Dias, D., Billion, P., Vandeputte, D. and Courtois, A., "Impedance functions of slab foundations with rigid piles", Geotechnical and Geological Engineering,  (2012), 1-12.
5.     Beer, M., Zhang, Y., Quek, S.T. and Phoon, K.K., "Reliability analysis with scarce information: Comparing alternative approaches in a geotechnical engineering context", Structural Safety,  Vol. 41, (2013), 1-10.
6.     Shooshpashaa, I., Mola-Abasia, H. and Amirib, I., "Evaluation of static and dynamic methods for determining the bearing capacity of the driven pipe piles", International Journal of Engineering,  Vol., No. 2, (2014), 27-35.
7.     Kermani, H., Behnamfar, F. and Morsali, V., "Seismic design of steel structures based on ductility and incremental nonlinear dynamic analysis", International Journal of Engineering-Transactions A: Basics,  Vol. 29, No. 1, (2015), 23-30.
8.     Huang, J. and Han, J., "Two-dimensional coupled hydraulic and mechanical modeling of geosynthetic-reinforced column-supported embankments", Comput Geotech,  Vol. 37, (2010), 638-648.
9.     Shen, Y. and Wang, H., "Optimization design on cfg-pile foundation with different cushion thickness in beijing-shanghai high-speed railway", Transportation Infrastructure Geotechnology,  Vol. 3, No. 1, (2016), 3-11.
10.   Moayed, R.Z., Izadi, E. and Mirsepahi, M., "3d finite elements analysis of vertically loaded composite piled raft", Journal of Central South University,  Vol. 6, No. 20, (2013), 1713-1723.
11.   Jiang, Y., Han, J. and Zheng, G., "Numerical analysis of a pile-slab-supported railway embankment", Acta Geotechnica,  Vol. 9, No. 3, (2014), 499-507.
12.   Messioud, S., Okyay, U.S., Sbartai, B. and Dias, D., "Dynamic response of pile reinforced soils and piled foundations", Geotechnical and Geological Engineering,  Vol. 3, No. 34, (2016), 789-805.
13.   Han, J., Bhandari, A. and Wang, F., "Dem analysis of stresses and deformations of geogrid-reinforced embankments over piles", International Journal of Geomechanics,  Vol. 12, No. 4, (2011), 340-350.
14.   Chen, Q.-n., Zhao, M.-h., Zhou, G.-h. and Zhang, Z.-h., "Bearing capacity and mechanical behavior of cfg pile composite foundation", Journal of Central South University of Technology,  Vol. 15, (2008), 45-49.
15.   Zhang, D., Zhang, Y., Cheng, T. and Yuan, J., "New analytic method for subgrade settlement calculation of the new cement fly-ash grave pile-slab structure", International Journal of Engineering-Transactions A: Basics,  Vol. 29, No. 10, (2016), 1364-1372.
16.   Ding-Bang, Z., Chuan-bob, Z., Yang-bob, L. and Jian-yia, Y., "Physical model test and numerical simulation study of deformation mechanism of wall rock on open pit to underground mining", International Journal of Engineering Transactions B Applications,  Vol. 27, No. 11, (2014), 1795-1802.
17.   Habib, A.F., Morgan, M. and Lee, Y.R., "Bundle adjustment with self–calibration using straight lines", The Photogrammetric Record,  Vol. 17, No. 100, (2002), 635-650.
18.   Xin, L., Shu-wen, L., Shu-gen, W. and Wei-zhong, R., "Application of digital close range photogrammetry in physical model deformation measurement of highway slope", Science of Surveying and Mapping,  Vol. 5, (2011), 078.
19.   Ding-bang, Z., Yi, Z., Tao, C., Yuan, M., Kun, F., Ankit, G. and Akhil, G., "Measurement of displacement for open pit to underground mining transition using digital photogrammetry", Measurement,  (2017), 132-140.