Studies On Lining Water Leaking Mechanism And Grouting Governing In Operational Tunnels

With the rapid development of national economy,there is a large number of major infrastructure constructions in fields of traffic and hydroelectric engineering in China.Nowadays,China's tunnel construction has beening the largest scale,fastest development speed and highest construction difficulty all over the world.Due to tunnel geology conditions,geo-stress influence and construction deficiency,most tunnels have problems like water leakage,lining cracking,cavities.These problems have a serious impact on the safety and durability of tunnel structure and they threaten the healthy operation of tunnels,even the safety of passing cars and pedestrians.Therefore,the study on lining water leaking mechanism and its control techniques have great theoretical significances and engineering values.So far,water leaking mechanism of tunnel lining is not clear all over the world,and there is no fine detection method for water leakage and no effective evaluation method for the control of water leakage by grouting.Thus,water leakage control of tunnel lining has become the limitation of tunnel construction development and tunnel healthy operation.Therefore,by theoretical analysis,numerical simulation,major physical model test as well as field test,a systematic research of lining water leaking mechanism and its control techniques in operational tunnels has been studied.The main research results are as follows:(1)A possibility research of destruction of tunnel lining in the rich water broken rock masses is studied using discontinuous method.From the aspects of the timing and depth of lining support,the depth of grouting reinforcement area,the effect of grouting reinforcement and drainage conditions,the influence on tunnel lining stressing state and cracking situations is revealed.(2)The mechanism of leakage of fault channel tunnel lining is studied using finite element method,and the effects of faults with different dip angles and penetrances on the strained condition and cracking of tunnel lining are revealed.Based on resemble theory of fluid-solid coupling,a 3D model test system of tunnel lining water leakage disease is developed.By large-scale model test,for the case of tunnel passing through faults,the deformation,force condition,destruction of surrounding rock and lining,as well as water leaking features and causes are revealed.Moreover,the influence of water draining on lining pressure release is studied.(3)The grout diffusion mechanism of single-penetrating crack and non-penetrating crack is studied.After researches of grout migration patterns and mechanism of grout-rock coupling and splitting,single-penetrating crack grouting model and single non-penetrating crack grouting model are established,thus the deformation and grouting sealing mechanism of single-penetrating and non-penetrating crack are revealed.Experiment on reinforcing effect of different grouting materials on different angles of fractures is carried out,and finite element models of tunnel lining with cracks before and after grouting are developed.Numerical simulation is carried out and the evolution law of surrounding rock stress and displacement before and after grouting is revealed.(4)Based on geology radar detection,fine detection of tunnel lining deficiency and disease and evaluation method of grouting reinforcement are proposed.Through systematic forward modelling and numerical simulation imaging test,combination of reflection image,migration image and spectrum analysis is applied for recognizing the deficiency and disease like water leakage channels.By establishing the geology radar detection interpretation criteria for typical lining diseases,an evaluation criteria and method of grouting reinforcement for lining water leakage disease.In the end,based on 'reflection image,migration image and spectrum analysis',an integrated fine detection method for tunnel lining deficiency and disease and evaluation of grouting reinforcement is established.(5)Based on the Kaiyuan tunnel on the main east-west line Lvyou road in Jinan,the statistics and division of tunnel water leakage type is proposed.Applying the integrated analysis based on 'reflection image,migration image and spectrum analysis'for tunnel lining deficiency and disease fine detection and evaluation method for grouting reinforcement,an accurate recognition and positioning of lining cracking,cavity and water leakage.Through application of rubber water-stop and metal flow diverter,the problem of water leakage caused by choked drainage system and lining cracking can be solved.The grouting material of the kaiyuan tunnel was established according to laboratory results and field test,simultaneously,the governance principles and plans were formulated and implemented.The research results have successfully applied in the sealing of 122 lining water leakage in Kaiyuan tunnels and they ensure the integrity of tunnel structure and its safe operation.