Study On The Influence Of Grouting Compactness On The Mechanical Properties Of Tunnel Lining Reinforced By Corrugated Steel Plate

The railway construction continues to extend to remote and mountainous areas,and when crossing mountain areas with complex terrain conditions,the tunnel entrance and exit are very easy to form shallow buried bias.In the construction process of bias tunnel,due to improper construction technology,there are existing defects in the lining,which may produce large deformation and even lead to tunnel collapse.At present,the deformation mechanism of existing tunnel lining is unknown,and it is urgent to carry out research on the stress and deformation law of lining structure under bias load,and further explore the reinforcement method of tunnel lining structure.Aiming at the complex diseases such as lining cracking,water leakage,spalling block and emptying during railway tunnel operation,this thesis takes the Shuohuang heavy-haul railway tunnel engineering as the research background,designs the working conditions with different grouting compactness through theoretical derivation,model test and numerical simulation,explores the bearing capacity law of the lining structure under corrugated steel plate reinforcement,and effectively guides the reinforcement of the lining structure of heavy-haul railway tunnel,which has important theoretical and engineering significance.The main research work and conclusions are as follows:(1)On the basis of reviewing the research results at home and abroad,the mechanical properties of corrugated steel plate-concrete composite structure under bias load are further studied,the composite cross-sectional characteristics of corrugated steel plate-concrete composite structure in model test are explored,and the reinforcement advantages brought by the composite structure to tunnel lining are clarified,which provides theoretical and technical support for practical application.It is found that the thickness of overlying concrete and the thickness of corrugated steel plate have a great influence on the stiffness of the composite structure,and the influence of bending stiffness is particularly obvious.(2)Carry out similar model tests of corrugated steel plate reinforcement tunnel lining,explore the differences in mechanical properties of different parts of the lining structure under bias load under different grouting compactness,effectively reveal the progressive failure law of tunnel lining,and provide reference for the selection of reinforcement technology in practical applications.The test shows that the peak of pressure,bending moment,axial force and displacement of four kinds of corrugated steel plate reinforcement lining and non-corrugated steel plate reinforcement lining are located at the shoulder when the bearing capacity reaches the maximum when the bearing capacity reaches the maximum,followed by the vault and arch foot.Under the action of the maximum bearing capacity of the spank,the pressure,bending moment,axial force and displacement relationship of five working conditions: corrugated steel plate reinforcement under grouting dense lining> corrugated steel plate reinforcement under arch shoulder grouting undense lining> corrugated steel plate reinforcement under arch grouting undense lining> corrugated steel plate reinforcement under vault grouting undense lining > Corrugated steel plate reinforced lining;Under the bias load of corrugated steel plate reinforced shoulder,the undense grouting of the vault has the greatest influence on the stability of the tunnel lining structure.(3)According to the indoor model test,numerical simulation verification was carried out,and the finite element model of corrugated steel plate-concrete composite structure was established by ABAQUS,the bearing capacity difference of tunnel lining under different reinforcement conditions was verified and summarized,and the stiffness of tunnel lining was inverted and analyzed based on the test deformation data.The results show that the displacement of the five working conditions under the maximum load pressure of the left arch shoulder: grouting dense lining> arch shoulder grouting is not dense lining> arch waist grouting is not dense lining> vault grouting is not dense lining> no reinforced lining;Under the shoulder bias load,the bearing capacity of the vault grouting undense lining in the range of 30°～45° decreases the fastest.