XU Q F, JIN Z, LAI L J,et al.Study on the effect of servo strut control on retaining structure deformation and adjacent tunnel displacement induced by deep excavation[J].Journal of Henan Polytechnic University(Natural Science) ,2026,45(4):58-66.

doi:10.16186/j.cnki.1673-9787.2026030013

Received:2026/03/11

Revised:2026/05/14

Published:2026/06/17

Study on the effect of servo strut control on retaining structure deformation and adjacent tunnel displacement induced by deep excavation

Xu Qingfeng1, Jin Zheng1, Lai Lingjie2,3, Chen Ziyi2, Ying Hongwei2

1.Hangzhou Electric Power Design Co.， Ltd.，Hangzhou  310014， Zhejiang， China;2.Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering， Hohai University， Nanjing  210098， Jiangsu， China;3.Zhejiang Province Institute of Architectural Design and Research， Hangzhou  310008， Zhejiang， China

Abstract: Objectives The influence of servo strut control on the displacement of adjacent existing tunnels during deep excavation was analyzed.  Methods A two-dimensional finite element numerical model， based on a deep excavation project in soft soil in Hangzhou， was established. The small-strain hardening constitutive model was used to simulate soil behavior. The deformation mode of the retaining wall after applying the active deformation control technology using reinforced concrete double-waling servo struts was studied， along with its influence on the displacement and deformation of an adjacent existing shield tunnel. The influence zone of tunnel displacement induced by excavation was delineated and compared with that under the conventional wall deformation mode without servo struts.  Results The simulation results show that when the servo strut technology is applied with a relatively large strut force threshold， the retaining wall deforms in an S-shape， which is significantly different from the conventional inward convex deformation mode. Under servo strut control， shallow adjacent tunnels experience horizontal displacement away from the excavation， while tunnels located at greater depths still undergo horizontal displacement toward the excavation along with the wall. The maximum horizontal displacement still occurs near the excavation bottom close to the wall. When the tunnel is shallow， settlement occurs near the wall and slight heave occurs farther away； the tunnel deformation is dominated by horizontal convergence. When the tunnel is deeply buried， the tunnel deformation is mainly characterized by vertical convergence.  Conclusions The servo strut control technology is significantly effective in controlling the displacement of tunnels located very close to the excavation， but its effectiveness is limited for tunnels that are farther away and shallowly buried.

Key words:servo strut;excavation;metro tunnels;deformation patterns