Taking the Wuxi-Taicang Expressway Huishan Xincheng Tunnel underpassing the Wuxi Metro Line 1 viaduct (between Yanqiao Station and Xibei Canal Station) as an engineering example, the influence of tunnel foundation pit excavation on adjacent subway elevated is studied. Based on the Moore-Coulomb constitutive model, a three-dimensional finite element model was established by the combination of entity-structure composite elements, combined with elastic theory calculations and measured data of similar projects, and the influence of tunnel foundation pit construction on the surrounding soil and adjacent elevated bridge deformation was analyzed. Combining the deformation of the two, the corresponding viaduct protection measures and foundation pit support schemes are proposed, and the following conclusions are obtained: 1) The maximum horizontal displacement of the viaduct is 2.45mm, the maximum vertical displacement is 2.83mm, and the foundation pit retaining piles are obtained through numerical calculations. The maximum horizontal displacement is 5.43mm, and the maximum vertical displacement is 7.00mm, all of which have passed the verification and meet the requirements of the specification. 2) Comparing the displacement data of the retaining pile obtained by the numerical simulation with the calculation data of the traditional elastic method and the actual monitoring data of a certain project, the displacement laws of the three are consistent. The displacement value of the pile bottom is relatively small. 3) When the distance between the pile foundation and the foundation pit of the viaduct is relatively close, the supporting form of row piles + internal support is used with local soil reinforcement, which has a large foundation pit supporting rigidity and has a good effect on the protection of important structures.

Yu Lei, Lv Zhijia, Liu Yi, Zhang Juhua. Analysis of influence of excavation of small clear distance foundation pit on adjacent viaduct pile foundation. Academic Journal of Architecture and Geotechnical Engineering (2024) Vol. 6, Issue 4: 123-136. https://doi.org/10.25236/AJAGE.2024.060419.

[1] Ding Huaxing, Xie Jun, Chen Shougen. Research on the Deformation Effects of Newly-built Interchange Stations Below Existing Metro Stations[J]. Shanxi Architecture, 2021, v.47(24):84-87.

[2] Huang Wenbin, Wang Yuan, Sun Guofeng. Deformation calculation and monitoring analysis of the influence of excavation of foundation pit on adjacent subway viaduct[J]. Guangdong Civil Engineering and Construction, 2021, v.28;No.346(12):46-50.

[3] Peng Zhijia, Liu Wentao, Hu Linhao, Liu Shuanding, Mo Linfei. Research on the Mechanical Characteristics of Deep Foundation Pit Support Structure of Metro Station under Unbalanced Loads[J]. Roadbed Engineering, 2021, No.218(05):198-202.

[4] Rui Yongqin, An Yue, Wang Zhenhua, Yu Xiaosha. Numerical simulation of the construction mechanics characteristics of the foundation pit group under the bridge adjacent to the high-speed subway connecting line[J]. Journal of Shenyang Jianzhu University (Natural Science Edition), 2021, v.37; No.194

[5] Xu Guoyuan, Huang Siyuan. Calculation analysis of the influence of foundation pit excavation on the deformation of the underlying shield tunnel[J]. Journal of Chongqing Jiaotong University (Natural Science Edition), 2021, v.40;No.236(09):78-85

[6] Wang Hao, Liu Shuangqiao, Song Zhi, Cheng Kang, Zhou Hao, Cui Yaozong. Design and selection of super large and deep foundation pits adjacent to subway under complex environment and weathered rock conditions[J]. Construction Technology (Chinese and English), 2021, v.50 ; No.588(17):135-140.

[7] Yang Gongbiao. The mechanism of interaction between shallow tunnel and adjacent stratum cavity and its influence on stratum deformation[D]. Beijing Jiaotong University, 2021.

[8] Dai Bingqiang, Liu Yinchang, Zhou Guoliang, Yang Dongliang. Research on characteristic response of adjacent structure of deep excavation in loess[J]. Journal of Nanchang Institute of Technology, 2021, v.40; No. 153(04):41-47.

[9] Einstein H H. Risk and risk analysis in rock engineering [J]. Tunneling and Underground Space Technology, 1996, 11(2):141-155.

[10] Nilsen B, Palmstsm C, Stille H . Quality Control of a Sub-sea Tunnel Project in Complex Ground Conditions. Proc of ITA World Tunnel Congress Oslo, 1999:137-145.

[11] Heinz Duddeck. Challenges to tunneling engineers[J].Tunneling and Underground Space Technology, 1996, 11(1):5-10.

[12] Nie Xiaowei, Zhang Yuqing, Yang Dingcai.A risk assessment method based on AHP and fuzzy theory [J]. Beijing Electronic Science and Technology Institute, 2005, 13(2):44-49.

[13] Zhou Shuming, Pan Guodong. Risk Analysis and Control of Underwater Tunnel[J]. Chinese Journal of Underground Space and Engineering, 2012.8

[14] Gao Shufeng.Analysis of Risk Assessment of Yanshan Tunnel on Zhangtang Railway[J]. Construction Risk and Management, 2012.s1.038

[15] Song Haoran, Zhang Dingli.Research on Risk Assessment and Countermeasures of Dalian Bay Subsea Tunnel [J], Journal of Beijing Jiaotong University, 2013, 37(4) 

[16] Lin Zhi, Chen Wen, Chen Si.Study on the Operational Risk Assessment Method of Cross-sea Tunnel Based on Scenario Analysis[J].Engineering Construction, 2018, 50(90);5-11.

[17] Wu Senyang, Hu Xuebing.Study on the evaluation of highway tunnel operation safety grade[J]. Chinese Journal of Underground Space and Engineering, 2018(14):363-370.

[18] Li Yuanyuan. Analysis of the Influence of Foundation Pit Excavation on the Stress and Deformation of Existing Small Clear Distance Tunnels[J]. Jilin Water Resources, 2021, No.473(10):33-37.