| Soil adhesion is the phenomenon that clay adheres to the solid surface.In shield tunneling,the soil excavated by the cutter will adhere to the metal surface of the shield machine,the clay clogging problem will occur when the soil is extruded and consolidated.The clay will accumulate around the cutter,reduce the penetration of the cutter and lead to uneven wear,which will seriously reduce the shield tunneling efficiency and even cause construction safety problems.This thesis mainly studied the interface adhesion mechanism of soil and shield machinery and the influence law of different factors.The study was achieved by literature investigation,theoretical analysis,laboratory test,and case analysis.This thesis also made an effort in reducing the adhesion and summarized the engineering disposal methods of clay clogging.The research results can be applied to shield tunneling in various clay soil,provide theoretical basis and technical support for solving the problem of clay clogging in construction.The main research contents and research results are as follows:(1)This thesis introduced the model of interface adhesion,and the soil adhesion system from the properties of soil and metal.The cause of adhesion,the theoretical model of adhesion and the factors that affect adhesion were analyzes.(2)Four common mineral soil samples and one soil sample from construction project were used to carry out indoor tests through self-made interface adhesion pull-out test equipment.The influence of sample moisture content,soil sample type,metal surface properties,pressure magnitude,compression time and drawing speed were obtained.(3)The effect of high pressure and high temperature on the adhesion between the clay and the metal was studied through the sealed adhesion test equipment.(4)The results of the adhesion test and the existing engineering clogging potential diagram were combined to assess judge the clay clogging risk.A preliminary study was conducted on the method of reducing the adhesion between the soil and the metal through adhesion tests.The prevention and disposal measures of common clay clogging problems are classified and discussed based on engineering cases. |
