Sains Malaysiana 46(11)(2017): 2231-2239

http://dx.doi.org/10.17576/jsm-2017-4611-25

Comparative Analysis of Load Responses and Deformation for Crust Composite Foundation and Pile-supported Embankment

(Perbandingan Analisis Respons Beban dan Kecemaran Asas Komposit Kerak dan Embankmen Disokong Longgokan)

YING WANG¹, YONGHUI CHEN^2*, ZHENHUA HU¹, QIANG FENG¹ & DESEN KONG¹

¹Shandong Provincial Key Laboratory of Civil Engineering, Disaster Prevention and Mitigation

Shandong University of Science and Technology, Qingdao 266590, China

²Geotechnical Research Institute, Hohai University, Nanjing 210098, China

Diserahkan: 8 Januari 2017/Diterima: 8 Jun 2017

ABSTRACT

Ground improvement using artificial crust composite foundation, consisting of stabilization of soft clay and composite foundation, is an effective technique for the treatment of deep soft soil layers under infrastructure embankments. In this study, the load responses and settlement performance of this improvement technique were investigated using two centrifuge model tests to compare the variations of the vertical deformation, pore water pressure, axial force of the piles and tensile stress at the bottom of the artificial crust in the crust composite foundation with those in pile-supported embankment. The results of centrifuge model tests showed that the load responses and settlement performance of artificial crust composite foundation was different from the pile-supported embankment, which displayed mainly that the final middle settlement of crust composite foundation can be reduced by about 15% compared with those of pile-supported embankment with the same length of pile and construction cost. The deformation of the crust with the characteristics of the plate was found based on the change of the tensile stress. Additionally, the excess pore water pressure in the crust composite foundation was lower owing to the stress diffusion effect of the crust during the loading period and the dissipation rate of excess pore water pressure was slower due to lower permeability of the crust at the same loading period. Eventually, the axial force of the middle piles was reduced. At the same time, the boundary stress was functioned with the crust, the axial force of the side piles was improved. The comparison of measured and calculated results was carried out using the stress reduction ratio, the result shows that the bearing capacity of the subsoil in the crust composite was improved.

Keywords: Artificial crust composite foundation; centrifuge model test; pile-supported embankment; soft clay; stabilization

ABSTRAK

Pembaikan tanah yang menggunakan asas komposit kerak tiruan, terdiri daripada penstabilan tanah liat lembut dan komposit asas, merupakan teknik yang berkesan untuk rawatan tanah lembut lapisan dalam di bawah infrastruktur benteng. Dalam kajian ini, beban tindak balas tindakan dan prestasi penempatan dalam teknik pembaikan ini dikaji menggunakan dua model ujian pengemparan untuk membandingkan perbezaan canggaan menegak, tekanan air liang, daya paksi cerucuk dan tekanan tegangan di bahagian bawah kerak tiruan dalam asas komposit kerak dengan cerucuk disokong benteng. Keputusan ujian model pengemparan menunjukkan bahawa beban tindak balas dan prestasi penempatan asas komposit kerak tiruan adalah berbeza daripada cerucuk disokong benteng, yang memaparkan asas penempatan tengah akhir, asas kerak komposit boleh dikurangkan kira-kira 15% berbanding dengan cerucuk disokong benteng dengan panjang cerucuk serta kos pembinaan yang sama. Canggaan kerak ini dengan ciri plat dijumpai berdasarkan perubahan tekanan tegangan. Di samping itu, tekanan air liang lebihan dalam asas komposit kerak adalah lebih rendah disebabkan kesan penyebaran tekanan kerak pada sepanjang tempoh bebanan dan kadar pelesapan tekanan air liang lebihan adalah lebih perlahan disebabkan oleh kadar resapan kerak yang lebih rendah pada tempoh beban yang sama. Kesimpulannya, daya paksi cerucuk di bahagian telah telah dikurangkan. Pada masa yang sama, tekanan sempadan berfungsi dengan kerak maka daya paksi cerucuk sisi bertambah baik. Perbandingan keputusan yang diukur dan dikira telah dijalankan menggunakan nisbah penurunan tekanan dan keputusan menunjukkan bahawa keupayaan galas tanah bawah dalam komposit kerak adalah bertambah baik.

Kata kunci: Asas komposit kerak tiruan; benteng disokong cerucuk; model ujian pengemparan; penstabilan; tanah liat lembut

RUJUKAN

Ariyarathne, P. & Liyanapathirana, D.S. 2015. Review of existing design methods for geosynthetic-reinforced pile-supported embankments. Soils and Foundations 55(1): 17-34.

Blanc, M., Thorel, L., Girout, R. & Almeida, M. 2014. Geosynthetic reinforcement of a granular load transfer platform above rigid inclusions: Comparison between centrifuge testing and analytical modelling. Geosynthetics International 21(1): 37-52.

BS 8006. 2010. Code of Practice for Strengthened/Reinforced Soils and Other Fills. British Standard Institution, UK.

Chen, R.P., Wang, Y.W., Ye, X.W., Bian, X.C. & Dong, X.P. 2016. Tensile force of geogrids embedded in pile-supported reinforced embankment: A full-scale experimental study. Geotextiles & Geomembranes 44(2): 157-169.

Chen, R.P., Chen, Y.M., Han, J. & Xu, Z.Z. 2008. A theoretical solution for pile-supported embankments on soft soils under one-dimensional compression. Canadian Geotechnical Journal 45: 611-623.

Erfen, H.F.W.S., Asis, J., Abdullah, M., Musta, B., Tahir, S., Pungut, H. & Mohd Husin, M.A.Y. 2017. Geochemical characterization of sediments around Nukakatan Valley, Tambunan, Sabah. Geological Behavior 1(1): 13-15.

Fagundes, D.F., Almeida, M.S.S., Thorel, L. & Blanc, M. 2017. Load transfer mechanism and deformation of reinforced piled embankments. Geotextiles & Geomembranes 45(2): 1-10.

Garnier, J., Gaudin, C. & Springman, S.M. 2007. Catalogue of scaling laws and similitude questions in geotechnical centrifuge modelling. International Journal of Physical Modelling in Geotechnics 7(3): 1-23.

Hewlett, W.J. & Randolph, M.F. 1988. Analysis of piled embankments. Ground Engineering 21(3): 12-18.

Huang, J. & Han, J. 2009. 3D coupled mechanical and hydraulic modeling of a geosynthetic-reinforced deep mixed column-supported embankment. J. Geotextile Geomembr. 27(4): 272-280.

Ishihara, K. 1993. Liquefaction and flow failure during earthquakes. Géotechnique 43(3): 351-451.

Ishikura, R., Yasufuku, N. & Brown, M.J. 2016. An estimation method for predicting final consolidation settlement of ground improved by floating soil cement columns. Soils & Foundations 56(2): 213-227.

Ishikura, R., Ochiai, H., Yasufuku, N. & Omine, K. 2007. Estimation of the settlement of improved ground with floating-type cement-treated columns. Proceedings of the 4th International Conference on Soft Soil Engineering, Vancouver. pp. 625-635.

Jelisic, N. & Leppänen, M. 2003. Mass stabilization of organic soils and soft clay. Proceedings of the 3th International Conference on Grouting and Ground Treatment, New Orleans, Louisiana. pp. 552-561.

Liu, W., Qu, S., Zhang, H. & Nie, Z. 2017. An integrated method for analyzing load transfer in geosynthetic-reinforced and pile-supported embankment. KSCE Journal of Civil Engineering 21(3): 687-702.

Ng, C.W.W. 2014. The state-of-the-art centrifuge modelling of geotechnical problems at hkust. Journal of Zhejiang University-Science A 15(1): 1-21.

Noor, M.J. & Ashraf, M.A. 2017. Accumulation and tolerance of radiocesium in plants and its impact on the environment. Environment Ecosystem Science 1(1): 13-16.

Rahman, M.M., Abdullah, R.B., Wan Khadijah, W.E., Nakagawa, T. & Akashi, R. 2014. Feed intake and growth performance of goats offered Napier grass (Pennisetum purpureum) supplemented with concentrate pellet and soya waste. Sains Malaysiana 43(7): 967-971.

Sharma, J.S. & Bolton, M.D. 1996. Centrifuge modelling of an embankment on soft clay reinforced with a geogrid. Geotextiles & Geomembranes 14(1): 1-17.

Stewart, M.E. & Filz, G.M. 2014. Influence of clay compressibility on geosynthetic loads in bridging layers for column-supported embankments. Geo-frontiers Congress 156(130): 1-14.

Taylor, R.N. 1995. Geotechnical Centrifuge Technology. London: Blackie Academic and Professional.

van Eekelen, S.J.M., Bezuijen, A. & van Tol, A.F. 2011. Analysis and modification of the British Standard BS8006 for the design of piled embankments. Geotextiles & Geomembranes 29(3): 345-359.

Viswanadham, B.V.S. & Mahajan, R. 2004. Modeling of geotextile reinforced highway slopes in a geotechnical centrifuge. In Geotechnical Engineering for Transportation Project, edited by Yegian, M.K. & Kavazanjian, E. Proceedings of Geo-Trans. pp.637-646.

White, D.J., Take, W.A. & Bolton, M.D. 2003. Soil deformation measurement using particle image velocimetry (PIV) and photogrammetry. Géotechnique 53(7): 619-631.

Yao, M.Y., Zhou, S.H. & Li, Y.C. 2004. Boundary effect analysis of centrifuge test. Chin Q Mech. 25(2): 291-296.

Yapage, N.N.S., Liyanapathirana, D.S., Kelly, R.B., Poulos, H.G. & Leo, C.J. 2014. Numerical modeling of an embankment over soft ground improved with deep cement mixed columns: Case history. Journal of Geotechnical & Geoenvironmental Engineering 140(11): 04014062.

Zhang, L., Zhao, M., Hu, Y., Zhao, H. & Chen, B. 2012. Semi-analytical solutions for geosynthetic-reinforced and pile-supported embankment. Computers & Geotechnics 44(44): 167-175.

Zheng, G., Jiang, Y., Han, J. & Liu, Y.F. 2011. Performance of cement-fly ash-gravel pile-supported high-speed railway embankments over soft marine clay. Marine Georesources & Geotechnology 29(2): 145-161.

Zhuang, Y., Ellis, E. &Yu, H.S. 2012. Three-dimensional finite-element analysis of arching in a piled embankment. Géotechnique 62(12): 1127-1131.

*Pengarang untuk surat-menyurat; email: jiang101215@163.com