Unified Analytic Elasto-plastic Solution Of Deep Circular Hydraulic Tunnel With Effects Of Liner-grout-rock Ground Water

As a common utility in underground engineering,deep circular hydraulic tunnel shares loads,like rock in-situ stress,seepage force and other external loads,by lining-grouting-rock mass together.For the purpose of safety,it is necessary to take lining-grouting-rock mass-underground water as whole stress balance system for the elastoplastic stress analysis in detail throughout the design and excavation as well as operating periods of deep tunnel.At present,only the influence of single factor,like the property of lining,seepage force,strain-softening,etc.,is considered in the elasto-plastic solution for a deep circular hydraulic tunnel.Therefore,based on the twin and triple shear unified strength theory,to develop elasto-plastic analytical solution for exploring the distribution of stress field with consideration of the interaction between lining-grouting-rock mass and underground water and the effect of intermediate stress as well as the order of major principal stress under combination of different loads and to realize the visualization of elastoplastic analysis in this paper.The main research contents and findings are presented as follows:(1)To develop twin-shear unified analytical solution for elasto-plastic stress of a deep circular hydraulic tunnel.Under axisymmetric plane strain conditions,the lining,grouting and rock mass are assumed to be elasto-plastic and governed by the twin-shear unified strength theory.In terms of the excavation and operating periods of deep circular hydraulic tunnel and considering the cases of elasto-plastic interface occurs in lining,grouting and rock mass,respectively,the twin-shear unified analytical solutions for elastoplastic stress of deep circular hydraulic tunnel are presented with consideration of grouting and no grouting between lining and rock mass.(2)The triple-shear unified strength theory is used to present unified analytical solution for elasto-plastic stress of a deep circular hydraulic tunnel.Under axisymmetric plane strain conditions,the lining,grouting and rock mass are assumed to be elastoplastic and governed by the triple-shear unified strength theory.In terms of the excavation and operating periods of deep circular hydraulic tunnel and considering the cases of elasto plastic interface occurs in lining,grouting and rock mass,respectively,the triple–shear unified analytical solutions for elasto-plastic stress of deep circular hydraulic tunnel are presented with consideration of grouting and no grouting between lining and rock mass..(3)Parameter analysis was conducted for both the twin-shear and triple-shear unified analytical solution.In terms of twin-shear and triple-shear unified analytical solution for elasto-plastic stress of a deep circular hydraulic tunnel with consideration of grouting,parameter analysis was conducted for the case of elasto-plastic interface occurs in lining under tunnel excavation period,elasto-plastic stress distribution laws of deep circular hydraulic tunnel were identified.(4)Visualization system for elasto-plastic analysis of a deep circular tunnel.Under the user requirements,the visualization system can performance well for elasto-plastic analysis of a deep circular tunnel both in excavation and operating periods.The visualization system for elasto-plastic analysis of a deep circular tunnel includes parameter inputting and saving module,calculating the plastic zone radius and elastic-plastic stress module as well as the results displaying and saving module.Based on the theory of groundwater seepage and the assumption of radial stable seepage of deep circular tunnel,to develop visualization software for calculating seepage pressure acting on the lining,grouting circle and surrounding rock mass around deep circular tunnel.