Stress Change Characteristics of the Existing Tunnel Surrounding Rocks by In-situ Expansion

doi:10.12068/j.issn.1005-3026.2023.04.015

Abstract

Abstract: In order to evaluate the stress disturbance degree and redistribution characteristics of the expansion and excavation of existing tunnels， taking the in-situ expansion project of the Nanling single-track railway tunnel as the research background， based on the classical elastic-plastic theory， and combined with the Mohr-Coulomb yield criterion， the calculation formulas of the surrounding rock diameter and circumferential stress change during the expansion process were deduced， and the influences of different formation conditions， initial stress， and equal-circle calculation methods on stress change were analyzed. The results showed that the second excavation causes the radial stress to decrease in varying degrees compared with that before the expansion， and the circumferential stress first decreases and then increases， and finally remains in the original stress state; the surrounding rock stress distribution state is closely related to the surrounding rock conditions， initial stress， equal-circle calculation methods， and the simplified calculation method of the equal-circle calculation of the sum of 1/4 height and span has good applicability to the calculation of the stress change of the surrounding rocks for the in-situ expansion of a single-line tunnel. The on-site measurement has verified the accuracy of the calculation formula of stress change， and provided a theoretical basis for the design of the excavation scheme of expansion tunnels and the optimization of the support parameters.

Key words: tunnel engineering; in-situ expansion; second disturbance; stress evolution; change characteristics; sensitivity analysis

CLC Number:

U218

SUN Da-zeng， ZHAO Wen， WANG Xin， BAI Qian. Stress Change Characteristics of the Existing Tunnel Surrounding Rocks by In-situ Expansion[J]. Journal of Northeastern University(Natural Science), 2023, 44(4): 565-572.

References

[1]Chen Z L，Chen J Y，Liu H，et al.Present status and development trends of underground space in Chinese cities:evaluation and analysis［J］.Tunnelling and Underground Space Technology，2018，71:253-270.
[2]Cui J Q，Broere W，Lin D.Underground space utilisation for urban renewal［J］.Tunnelling and Underground Space Technology，2021，108:103726.
[3]彭念.原位扩建隧道围岩力学响应机理研究［D］.重庆:重庆大学，2010.(Peng Nian.Research on mechanical response mechanism of surrounding rock of in-situ extension tunnel［D］.Chongqing:Chongqing University，2010.)
[4]Peng N，Zhang Y X，Wang C.Study on mechanical properties of surrounding rock during tunnel construction with in-situ expansion step excavation method［J］.Disaster Advances，2010，3(4):194-199.
[5]Nikadat N，Marji M F.Analysis of stress distribution around tunnels by hybridized FSM and DDM considering the influences of joints parameters［J］.Geomechanics and Engineering，2017，11(2):269-288.
[6]Gao C L，Zhou Z Q，Li Z H，et al.Peridynamics simulation of surrounding rock damage characteristics during tunnel excavation［J］.Tunnelling and Underground Space Technology，2020，97:103289.
[7]Zhao K，Bonini M，Debernardi D，et al.Computational modelling of the mechanised excavation of deep tunnels in weak rock［J］.Computers and Geotechnics，2015，66:158-171.
[8]黄伦海，钱七虎.公路隧道大断面改扩建施工开挖方案研究［J］.现代隧道技术，2016，53(5):145-153，160.(Huang Lun-hai，Qian Qi-hu.Study on excavation schemes for the redevelopment construction of highway tunnels with large sections［J］.Modern Tunnelling Technology，2016，53(5):145-153，160.)
[9]来弘鹏，徐学深，常瑞成，等.公路隧道扩建力学特征研究［J］.中国公路学报，2014，27(1):84-93.(Lai Hong-peng，Xu Xue-shen，Chang Rui-cheng，et al.Study on mechanical characteristics of highway tunnel expansion［J］.China Journal of Highway and Transport，2014，27(1):84-93.)
[10]张俊儒，史博然，汪家雷，等.塌方段原位扩建四车道公路隧道“回填-台阶法”施工力学及安全分析［J］.中国公路学报，2021，34(6):109-124.(Zhang Jun-ru， Shi Bo-ran，Wang Jia-lei，et al.Construction mechanics and safety analysis of“backfill-bench method”for in-site expansion of four-land highway tunnel in collapsed section［J］.China Journal of Highway and Transport，2021，34(6):109-124.)
[11]Jia Y L，Ouyang A H，Wang S Y，et al.Development and application of model test system for reconstruction and expansion of existing shallow single-hole tunnel into twin-arch tunnel［J］.Advances in Civil Engineering，2021，2021:6656165.
[12]Jia Y L，Xia Y X，Chen X D，et al.Force and deformation characteristics during the reconstruction and expansion of shallow single-tube tunnels into large-span multiarch tunnels［J］.Advances in Materials Science and Engineering，2019，2019:2783784.
[13]Yang S，Shi B R，Liu H.Study on construction mechanics of in-situ expansion of ultra-large flat tunnel in collapse section of an existing tunnel［J］.IOP Conference Series:Earth and Environmental Science，2020，570(2):022068.
[14]杨宾，林从谋，张在晨，等.隧道原位单侧扩挖围岩力学特性解析分析［J］.地下空间与工程学报，2018，14(6):1458-1465.(Yang Bin，Lin Cong-mou，Zhang Zai-chen，et al.Mechanical characteristics analysis of surrounding rock of unilateral expansion tunnels in situ［J］.Chinese Journal of Underground Space and Engineering，2018，14(6):1458-1465.)