Force Calculation of Mechanical Model of Pile-anchored Support Structure Based on Elastic Foundation Beam Method
DOI:
https://doi.org/10.13052/ejcm2642-2085.3224Keywords:
Mechanical model, force calculation, elastic foundation beam, pile-anchor support, deep foundation pitAbstract
With the widespread use of deep foundation pit engineering in engineering construction, the force calculation problem about deep foundation pit support engineering has become a common problem in today’s engineering construction process. In this paper, based on the elastic foundation beam method, a simplified mechanical model of pile-anchored structure is proposed, and a systematic and practical calculation method is proposed for the force and deformation calculation of deep foundation pit support structure. The method simplifies the support structure as a vertically placed elastic foundation beam, the support, anchor and geotechnical body are replaced by a spring system, the spring stiffness of geotechnical soil can be calculated by the deformation modulus of geotechnical soil, and a systematic calculation method is proposed for the dynamic characteristics of the construction and structure of the foundation pit project; Based on the monitoring data of a deep foundation pit project, the calculation method of the simplified mechanical model proposed in this paper is verified, and the theoretical calculation value is compared with the field monitoring results; Single factor analysis is carried out on the detailed parameters of pile-anchor supporting structure to study the influence of cable prestress, cable dip Angle, pile diameter, pile length and other related parameters on the deformation and stress characteristics of supporting structure. Then the orthogonal combination of all factors is carried out to propose the optimization design. The results show that the maximum settlement deformation of the calculated value is 23.437 mm, and the maximum settlement deformation of the monitored value is 26.517 mm, and the difference between them is small. The maximum bending moment is 1210 kN⋅m after 150 kN and 250 kN horizontal prestressing is added to the second- and third-layer anchors respectively. After optimization, the maximum bending moment of pile row is 336.87 kN⋅m, and the maximum horizontal displacement of pile body is 16.505 mm, which is reduced by 11.97% compared with the original design.
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Sun Y, Xiao H. Wall displacement and ground-surface settlement caused by pit-in-pit foundation pits in soft clays[J]. KSCE Journal of Civil Engineering, 2021, 25(4): 1262–1275.
Zhu Guichun, Liu Xingxin, Han Wujuan. Study on force deformation and optimal design of pile-anchor support system for deep foundation pits[J]. Safety and Environmental Engineering, 2012, 19(1): 124–128.
He Meide, Le Guiping, Liu Jun, et al. Analysis of force and deformation characteristics of a foundation pit enclosure structure in Olympic Park[J]. Journal of Geotechnical Engineering, 2008 (S1): 582–587.
Yang T, Li Y, Zhai X. Seismic Performance Analysis of Reinforced Concrete Frame Structures Based on Computational Mechanics[J]. European Journal of Computational Mechanics, 2021: 99–120.
Yang Z. F., Zhu Y. P., Guo N., et al. Experimental study on the internal forces of pile-anchor support structures in deep foundation pits of subway stations[J]. Geotechnical Mechanics, 2014, 2.
Wang T, Wüchner R, Bletzinger K U. Assessment and practical application of mapping algorithms for beam elements in computational FSI[J]. European Journal of Computational Mechanics, 2016, 25(5): 417–445.
Li HW, Nie QK. Evolution of deformation and force state of pile-anchor support structure during deep foundation excavation[J]. Journal of Coal, 2011 (S2): 315–320.
Mallardo V, Ruocco E. A NURBS boundary-only approach in elasticity[J]. European Journal of Computational Mechanics, 2016, 25(1–2): 71–90.
Han S, Yang K, Wei X, et al. Analysis of the influence of inside and outside water level changes of foundation pit on stability of foundation[C]//2016 2nd International Conference on Architectural, Civil and Hydraulics Engineering (ICACHE 2016). Atlantis Press, 2016: 280–284.
Shen Y G, Li X Q, Du N J, et al. Research on Analysis and Control of Seepage Failure in Foundation Pit[C]//Advanced Materials Research. Trans Tech Publications Ltd, 2012, 368: 3171–3174.
Liu Yang. Design and stability study of pile-anchored support structure for deep foundation pit of Dingfuzhuang resettlement house in Beijing [D]. Jilin University, 2018.
Zhang D D. Coupled numerical simulation research on dewatering and land subsidence in deep foundation pit[C]//Applied Mechanics and Materials. Trans Tech Publications Ltd, 2013, 275: 1549–1552.
Qiu J, Li F. The Application of Foundation Pit Monitoring Technology to the Excavation[C]//MATEC Web of Conferences. EDP Sciences, 2015, 22: 04004.
Yang Guanghua. Practical calculation methods for deep foundation pit support structures and their applications [M]. Geological Press, 2004.
Wang Y, Fang X, Fei W, et al. Development and Application of BIM-based Foundation Pit Construction Simulation System[C]//IOP Conference Series: Earth and Environmental Science. IOP Publishing, 2021, 714(2): 022062.
Nie S M, Ren F. Study on risk management of deep foundation pit engineering[C]//Applied Mechanics and Materials. Trans Tech Publications Ltd, 2014, 638: 574–579.
Shao Quan, Xu Xuelian, Xu Song, et al. Three-dimensional numerical analysis of deformation influencing factors of combined pile-anchor bracing support structures in deep foundation pits[J]. Journal of Geotechnical Engineering, 2014, 36(zk2): 87–91.
Zhang J X, Dai J L, Liu B. Application of Comprehensive Evaluation Method to Foundation Pit Engineering[C]//Advanced Materials Research. Trans Tech Publications Ltd, 2012, 446: 1775–1780.
Yu Chenglong. Research on deformation characteristics and optimal design of a deep foundation pit pile anchor support structure in Changde [D]. Xiangtan University, 2019.
Jiao S H, Wang J A, Liu Y M. Exploration and Practice of Innovative Support System of Large-Scale Deep Foundation Pit in Beijing[C]//Advanced Materials Research. Trans Tech Publications Ltd, 2014, 838: 747–755.
Zheng Weifeng, Shao Longtan, Jia Jinqing. Stress distribution law and application of prestressed anchor rod anchorage section in deep foundation pit[J]. Journal of Liaoning University of Engineering and Technology: Natural Science Edition, 2008, 27(6): 862–865.
Gao X, Wang W. Analysis of influence of adjacent side length of deep foundation pit on pit angle effect[C]//IOP Conference Series: Materials Science and Engineering. IOP Publishing, 2019, 592(1): 012127.
Zhang C M. Applications of soil nailed wall in foundation pit support[C]//Applied Mechanics and Materials. Trans Tech Publications Ltd, 2013, 353: 969–973.
Zhang Qinxi, Chen Peng, Yin Wenbiao. Monitoring study on the foundation support project of China World Trade Center Phase III[J]. Journal of Rock Mechanics and Engineering, 2012, 31(11): 2319–2326.
Chen S, Cui J, Liang F. Case study on the deformation coupling effect of a deep foundation pit group in a coastal soft soil area[J]. Applied Sciences, 2022, 12(12): 6205.
Chen S, Cui J, Liang F. Centrifuge model investigation of interaction between successively constructed foundation pits[J]. Applied Sciences, 2022, 12(16): 7975.
