| Based on the actual project of Jinan Tai’an expressway,based on a large number of tunnel karst treatment data and engineering practice,using the methods of theoretical analysis,numerical simulation and summary,this paper studies and analyzes the influence of karst filling type,water filling cave size and water pressure,grouting ring reinforcement thickness and permeability coefficient on the external water pressure and seepage field of tunnel lining,On the basis of the above research results,the prevention and control technology of tunnel karst is studied.The main research contents and conclusions are as follows(1)Based on the xiaofosi tunnel of Jinan Tai’an expressway,the influence of the type of karst filling,the size of water filled cave and the water pressure on the distribution of external water pressure and seepage law of tunnel lining is revealed by numerical calculation.(2)According to the characteristics of karst tunnel seepage law with many influencing factors and complicated influencing rules,the numerical simulation method is used to reveal the distribution law of tunnel water pressure and the internal force response of lining structure under the conditions of different thickness and permeability coefficient of grouting circle around the tunnel.With the increase of the thickness of grouting ring,the lining water pressure decreases,which leads to the internal force value of the lining generally decreases,so increasing the thickness of grouting ring is conducive to the structural safety;with the gradual decrease of the permeability coefficient of grouting ring,the lining water pressure decreases,and the safety coefficient of tunnel lining structure increases,so the gradual decrease of the permeability coefficient of grouting ring,that is,the improvement of the grouting water plugging effect,is conducive to the structural safety.(3)Based on the actual working state of karst tunnel lining structure and the status quo of disease prevention and control,the prevention principle of water and mud inrush in karst tunnel and the treatment principle of karst water in water rich karst cavity are studied,and the prevention technology of tunnel water rich karst is further studied.First,the scale,water volume,water pressure and other key factors of karst cavity are fully considered,and the water abundance degree of karst cavity is graded.Then,combined with the karst geological characteristics and the actual working state of tunnel lining structure,the scale countermeasures,filling countermeasures and water countermeasures are formulated according to local conditions,so as to realize the standardized treatment of karst.Figure[45]table[20]reference[53]... |
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