CLC number: TU4
On-line Access: 2024-08-27
Received: 2023-10-17
Revision Accepted: 2024-05-08
Crosschecked: 2018-03-07
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Hai-zuo Zhou, Gang Zheng, Xiao-xuan Yu, Tian-qi Zhang, Jing-jin Liu. Bearing capacity and failure mechanism of ground improved by deep mixed columns[J]. Journal of Zhejiang University Science A, 2018, 19(4): 266-276.
@article{title="Bearing capacity and failure mechanism of ground improved by deep mixed columns",
author="Hai-zuo Zhou, Gang Zheng, Xiao-xuan Yu, Tian-qi Zhang, Jing-jin Liu",
journal="Journal of Zhejiang University Science A",
volume="19",
number="4",
pages="266-276",
year="2018",
publisher="Zhejiang University Press & Springer",
doi="10.1631/jzus.A1700517"
}
%0 Journal Article
%T Bearing capacity and failure mechanism of ground improved by deep mixed columns
%A Hai-zuo Zhou
%A Gang Zheng
%A Xiao-xuan Yu
%A Tian-qi Zhang
%A Jing-jin Liu
%J Journal of Zhejiang University SCIENCE A
%V 19
%N 4
%P 266-276
%@ 1673-565X
%D 2018
%I Zhejiang University Press & Springer
%DOI 10.1631/jzus.A1700517
TY - JOUR
T1 - Bearing capacity and failure mechanism of ground improved by deep mixed columns
A1 - Hai-zuo Zhou
A1 - Gang Zheng
A1 - Xiao-xuan Yu
A1 - Tian-qi Zhang
A1 - Jing-jin Liu
J0 - Journal of Zhejiang University Science A
VL - 19
IS - 4
SP - 266
EP - 276
%@ 1673-565X
Y1 - 2018
PB - Zhejiang University Press & Springer
ER -
DOI - 10.1631/jzus.A1700517
Abstract: Extensive research has investigated the bearing capacity of footings placed on leveled ground improved by deep mixed (DM) columns. However, few studies have focused on the effects of the embedment on the bearing capacity of footings on ground reinforced with DM columns. In geotechnical engineering practice underestimation of the limit load has occurred in China because of the increased use of conventional design methods for reinforced ground with embedment. In this investigation, a numerical model using a rigorous limit analysis tool, known as discontinuity layout optimization (DLO), is established. An equivalent area model is employed with an appropriate stress concentration ratio. Subsequently, a set of design charts of bearing capacity coefficients is produced with a special focus on the bearing capacity coefficient Nq and the failure mechanism. The results show that three failure patterns exist in the composite ground reinforced by DM columns. For cases without embedment, the bearing capacity coefficient Nc increases with the area replacement ratio to a certain value due to the occurrence of general shear failure mechanism. The bearing capacity coefficient Nγ decreases with the area replacement ratio, as the equivalent frictional strength of the reinforced region is reduced. When the embedment is considered, the failure mechanism of composite foundation has a significant influence on the coefficient Nq. Specifically, increase of column length leads to a larger value of Nq when block failure is observed. When a general shear failure pattern occurs, the effect of additional column lengths on the coefficient Nq can be neglected.
[1]Aboshi H, Ichimoto E, Enoki M, et al., 1979. The compozer–a method to improve characteristics of soft clays by inclusion of large diameter sand columns. Proceedings of the International Conference on Soil Reinforcement: Reinforced Earth and Other Techniques.
[2]Abusharar SW, Han J, 2011. Two-dimensional deep-seated slope stability analysis of embankments over stone column-improved soft clay. Engineering Geology, 120(1-4):103-110.
[3]Bouassida M, Porbaha A, 2004. Ultimate bearing capacity of soft clays reinforced by a group of columns: application to a deep mixing technique. Soils and Foundations, 44(3):91-101.
[4]Bouassida M, Jelali B, Porbaha A, 2009. Limit analysis of rigid foundations on floating columns. International Journal of Geomechanics, 9(3):89-101.
[5]Broms BB, 1991. Stabilization of soil with lime columns. In: Fang HY (Ed.), Foundation Engineering Handbook. Springer, Boston, USA, p.833-855.
[6]Broms BB, 2000. Lime and lime/columns. Summary and visions. Proceedings of the 4th International Conference on Ground Improvement Geosystems, p.43-93.
[7]Bruce DA, 2001a. An Introduction to the Deep Mixing Methods as Used in Geotechnical Applications, Volume III: the Verification and Properties of Treated Ground. Report No. FHWA-RD-99-167, the National Academies of Sciences, Engineering, and Medicine, USA.
[8]Bruce DA, 2001b. Practitioner’s guide to the deep mixing method. Proceedings of the Institution of Civil Engineers– Ground Improvement, 5(3):95-100.
[9]Cai YQ, Xu CJ, 2002. Consolidation behavior of cement- and lime/cement-mixed column foundations. Journal of Zhejiang University-SCIENCE, 3(5):507-512.
[10]Chai JC, Shrestha S, Hino T, et al., 2015. 2D and 3D analyses of an embankment on clay improved by soil-cement columns. Computers and Geotechnics, 68:28-37.
[11]Chai JC, Shrestha S, Hino T, et al., 2017. Predicting bending failure of CDM columns under embankment loading. Computers and Geotechnics, 91:169-178.
[12]Dehghanbanadaki A, Ahmad K, Ali N, 2016. Experimental investigations on ultimate bearing capacity of peat stabilized by a group of soil-cement column: a comparative study. Acta Geotechnica, 11(2):295-307.
[13]Duan Y, Zhang YP, Chan D, et al., 2012. Theoretical elastoplastic analysis for foundations with geosynthetic-encased columns. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 13(7):506-518.
[14]Enoki M, Yagi N, Yatabe R, et al., 1991. Shearing characteristic of composite ground and its application to stability analysis. In: Deep Foundation Improvements: Design, Construction, and Testing. ASTM International, USA.
[15]Fattah MY, Shlash KT, Al-Waily MJM, 2011. Stress concentration ratio of model stone columns in soft clays. Geotechnical Testing Journal, 34(1):50-60.
[16]Han J, 2015. Principles and Practice of Ground Improvement. John Wiley & Sons, USA.
[17]Hanna AM, Etezad M, Ayadat T, 2013. Mode of failure of a group of stone columns in soft soil. International Journal of Geomechanics, 13(1):87-96.
[18]Horpibulsuk S, Miura N, Koga H, et al., 2004. Analysis of strength development in deep mixing: a field study. Proceedings of the Institution of Civil Engineers–Ground Improvement, 8(2):59-68.
[19]Huang J, Han J, 2009. 3D coupled mechanical and hydraulic modeling of a geosynthetic-reinforced deep mixed column-supported embankment. Geotextiles and Geomembranes, 27(4):272-280.
[20]Juran I, Guermazi A, 1988. Settlement response of soft soils reinforced by compacted sand columns. Journal of Geotechnical Engineering, 114(8):930-943.
[21]Karstunen M, 1999. Alternative ways of modelling embankments on deep-stabilized soil. Proceedings of the International Conference on Dry Mix Methods for Deep Soil Stabilization, p.221-228.
[22]Kitazume M, Yamamoto M, 1998. Stability of group column type DMM ground. Report of Port and Harbour Institute, 37(2):3-28.
[23]Kitazume M, Terashi M, 2002. The Deep Mixing Method– Principle, Design and Construction. Coastal Development Institute of Technology, Japan.
[24]Kitazume M, Yamamoto M, Udaka Y, 1999. Vertical bearing capacity of column type DMM ground with low improvement ratios. Proceedings of the International Conference on Dry Mix Methods for Deep Soil Stabilization, p.245-250.
[25]Kitazume M, Okano K, Miyajima S, 2000. Centrifuge model tests on failure envelope of column type deep mixing method improved ground. Soils and Foundations, 40(4):43-55.
[26]Leshchinsky B, 2015. Bearing capacity of footings placed adjacent to c′-φ′ slopes. Journal of Geotechnical & Geoenvironmental Engineering, 141(6):04015022.
[27]Liu W, Albers B, Zhao Y, et al., 2016. Upper bound analysis for estimation of the influence of seepage on tunnel face stability in layered soils. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 17(11):886-902.
[28]Okumura T, 1996. Deep mixing method of Japan. Grouting and deep mixing. Proceedings of the 2nd International Conference on Ground Improvement Geosystems, p.879-887.
[29]Omine K, Ochiai H, Bolton MD, 1999. Homogenization method for numerical analysis of improved ground with cement treated soil columns. Proceedings of the International Conference on Dry Dry Mix Methods for Deep Soil Stabilization, p.161-168.
[30]Porbaha A, 1998. State of the art in deep mixing technology: part I. Basic concepts and overview. Proceedings of the Institution of Civil Engineers–Ground Improvement, 2(2):81-92.
[31]Porbaha A, Bouassida M, 2004. Bearing capacity of foundations resting on soft ground improved by soil cement columns. International Conference on Geotechnical Engineering, p.172-179.
[32]Priebe HJ, 1995. The design of vibro replacement. Ground Engineering, 28(10):31.
[33]Rashid A, Safuan A, 2011. Behavior of Weak Soils Reinforced with Soil Columns Formed by Deep Mixing Method. PhD Thesis, University of Sheffield, UK.
[34]Rashid ASA, Black JA, Kueh ABH, et al., 2015. Behaviour of weak soils reinforced with soil cement columns formed by the deep mixing method: rigid and flexible footings. Measurement, 68:262-279.
[35]Rashid ASA, Black JA, Kueh ABH, et al., 2017. Bearing capacity charts of soft soil reinforced by deep mixing. Proceedings of the Institution of Civil Engineers–Ground Improvement, 170(1):12-25.
[36]Sexton BG, Mccabe BA, Castro J, 2013. Appraising stone column settlement prediction methods using finite element analyses. Acta Geotechnica, 9(6):993-1011.
[37]Smith C, Gilbert M, 2007. Application of discontinuity layout optimization to plane plasticity problems. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 463(2086):2461-2484.
[38]Smith C, Gilbert M, 2013. Identification of rotational failure mechanisms in cohesive media using discontinuity layout optimization. Geotechnique, 63(14):1194-1208.
[39]Tan SA, Tjahyono S, Oo KK, 2008. Simplified plane-strain modeling of stone-column reinforced ground. Journal of Geotechnical and Geoenvironmental Engineering, 134(2):185-194.
[40]Tan TS, Goh TL, Yong KY, 2002. Properties of Singapore marine clays improved by cement mixing. Geotechnical Testing Journal, 25(4):422-433.
[41]Terzaghi K, 1943. Theoretical Soil Mechanics. Wiley, New York, USA.
[42]Wu Y, Diao H, Liu J, et al., 2016. Field studies of a technique to mitigate ground settlement of operating highways. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 17(7):565-576.
[43]Yapage NNS, Liyanapathirana DS, Kelly RB, et al., 2014. Numerical modeling of an embankment over soft ground improved with deep cement mixed columns: case history. Journal of Geotechnical and Geoenvironmental Engineering, 140(11):04014062.
[44]Ye GB, Zhang Z, Han J, et al., 2013. Performance evaluation of an embankment on soft soil improved by deep mixed columns and prefabricated vertical drains. Journal of Performance of Constructed Facilities, 27(5):614-623.
[45]Yin JH, Fang Z, 2010. Physical modeling of a footing on soft soil ground with deep cement mixed soil columns under vertical loading. Marine Georesources and Geotechnology, 28(2):173-188.
[46]Zhang Z, Han J, Ye G, 2014. Numerical investigation on factors for deep-seated slope stability of stone column-supported embankments over soft clay. Engineering Geology, 168(2):104-113.
[47]Zheng G, Zhou HZ, Diao Y, et al., 2015. Bearing capacity factor for granular pile composite ground in saturated soft clay. Chinese Journal of Geotechnical Engineering, 37(3):385-399 (In Chinese).
[48]Zhou HZ, Diao Y, Zheng G, et al., 2017. Failure modes and bearing capacity of strip footings on soft ground reinforced by floating stone columns. Acta Geotechnica, 12(5):1089-1103.
[49]Zhou HZ, Zheng G, Yin X, et al., 2018. The bearing capacity and failure mechanism of a vertically loaded strip footing placed on the top of slopes. Computers and Geotechnics, 94:12-21.
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