Double-row pile (DRP) retaining systems have been widely used in deep excavations in China. Soil between the front and back-row piles (FBP soil) is often improved to decrease the displacement of DRPs in soft soil areas, but the improvement efficiency has rarely been researched. A large and deep excavation supported by a DRP retaining system is introduced, and the effect of FBP soil improvement is discussed by comparing the finite element analysis and the monitoring results. Then, a parametric study of DRP using the finite element method considering the small strain of soil is conducted to investigate the effect of FBP soil improvement. It was shown that the pile deflection and bending moment decrease when the FBP soil is improved. Moreover, the most efficient way to minimize the pile deflection and bending moment is to improve the FBP soil around the excavation level. The FBP soil improvement 2—4 m below the pile head is not very useful for reducing the pile deflection and can be eliminated when the pile displacement limit is not very strict.
聂东清1，翟之阳1，张威1，李志2
. Finite Element Analysis of Effects of Improvement of Soil Between Double-Row Piles[J]. Journal of Shanghai Jiaotong University(Science), 2024
, 29(5)
: 919
-929
.
DOI: 10.1007/s12204-022-2501-y
[1] PARK J S, JOO Y S, KIM N K. New earth retention system with prestressed wales in an urban excavation[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2009, 135(11): 1596-1604.
[2] SIM J, JEONG S, KIM K. The effect of stabilizing piles on a self-supported earth-retaining wall [J]. Marine Georesources & Geotechnology, 2016, 34(3): 265-279.
[3] ZHENG G, NIE D, DIAO Y, et al. Numerical and experimental study of multi-bench retained excavations[J]. Geomechanics & Engineering, 2017, 13(5): 715-742.
[4] LIU G B, WANG W D. Excavation engineering manual[M]. 2nd ed. Beijing: China Building Industry Press,2009 (in Chinese).
[5] KIM C, KWON J, IM J C, et al. A method for analyzing the self-supported earth-retaining structure using stabilizing piles [J]. Marine Georesources & Geotechnology, 2012, 30(4): 313-332.
[6] CAI Y Q, WANG L Z, CHEN Y M, et al. Cases of deep pit excavation with retaining structure formed from double-row pile in soft clay [J]. Journal of Building Structures, 1997, 18(4): 70-76 (in Chinese).
[7] ZHENG G, LI X, LIU C, et al. Analysis of double-row piles in consideration of the pile-soil interaction [J].Journal of Building Structures, 2004, 25(1): 99-106(in Chinese).
[8] ZHOU Y J, YAO A J, LI H B, et al. Correction of earth pressure and analysis of deformation for double-row piles in foundation excavation in Changchun of China[J]. Advances in Materials Science and Engineering,2016, 2016: 9818160.
[9] OU C Y, WU T S, HSIEH H S. Analysis of deep excavation with column type of ground improvement in soft clay [J]. Journal of Geotechnical Engineering,1996, 122(9): 709-716.
[10] SHEN S L, LUO C Y, XIAO X C, et al. Improvement efficacy of RJP method in Shanghai soft deposit [C]//U.S.-China Workshop on Ground Improvement Technologies 2009. Orlando: American Society of Civil Engineers, 2009: 170-178.
[11] TAN Y, WEI B, LU Y, et al. Is basal reinforcement essential for long and narrow subway excavation bottoming out in Shanghai soft clay? [J]. Journal of Geotechnical and Geoenvironmental Engineering, 2019, 145(5): 05019002.
[12] IGNAT R, BAKER S, KARSTUNEN M, et al. Numerical analyses of an experimental excavation supported by panels of lime-cement columns [J]. Computers and Geotechnics, 2020, 118: 103296.
[13] ZHOU Z Y, NIE D Q, ZHANG W. Effect of passive zone improvement on the stability of a double-row pileretained excavation [M]//Proceedings of GeoShanghai 2018 International Conference: Advances in Soil Dynamics and Foundation Engineering. Singapore: Springer, 2018: 536-542.
[14] OU C Y, CHIOU D C, WU T S. Three-dimensional finite element analysis of deep excavations [J]. Journal of Geotechnical Engineering, 1996, 122(5): 337-345.
[15] LEE F H, YONG K Y, QUAN K C N, et al. Effect of corners in strutted excavations: Field monitoring and case histories [J]. Journal of Geotechnical and Geoenvironmental Engineering, 1998, 124(4): 339-349.
[16] Shanghai Construction and Management Commission. Technical code for excavation engineering: DG/TJ 08- 61-2018 [S]. Shanghai: Tongji University Press, 2018(in Chinese).
[17] HORPIBULSUK S, LIU M D, LIYANAPATHIRANA D S, et al. Behaviour of cemented clay simulated via the theoretical framework of the Structured Cam Clay model [J]. Computers and Geotechnics, 2010, 37(1/2):1-9.
[18] KONGSUKPRASERT L, TATSUOKA F. Small strain stiffness and non-linear stress-strain behaviour of cement-mixed gravelly soil [J]. Soils and Foundations,2007, 47(2): 375-394.
[19] LANG L, LI F D, CHEN B. Small-strain dynamic properties of silty clay stabilized by cement and fly ash[J]. Construction and Building Materials, 2020, 237:117646.
[20] LIANG Z R, LI Z C, LIU J. Strength tests on soilcement mixed piles by triaxial stirring machine [J]. Chinese Journal of Geotechnical Engineering, 2010,32(S2): 475-478 (in Chinese).
