| The freezing method has been widely used in the construction of subway connecting passages.During the construction process,there is a certain distance between the bottom end of the freezing pipe and the interface of the pipe segments,and the inner wall of the pipe fins has severe heat dissipation.This resulted in a freezing accident at the interface of the freezing pipe and the tunnel segment.In high-incidence areas,how to effectively deal with the problem of weak development of the frozen wall at the interface and eliminate the hidden engineering hazards that exist when the interface freezes needs to be solved urgently.In this paper,a combination of numerical simulation and physical simulation is used to propose a new type of frozen tunnel segment with freezing pipes.The development law of the freezing temperature field at the interface between the tunnel segment and the soil body with the freezing function is deeply investigated.First,a numerical simulation study of the freezing temperature field at the interface of the freezing tunnel segment and the soil is carried out.In the numerical analysis,the development law of the freezing temperature field under the typical parameters of the frozen concrete segment is obtained;Considering the position of the freezing pipe,the cross-sectional shape of the freezing pipe,the diameter of the freezing pipe,the distance between the freezing pipes,the initial ground temperature,the freezing pipe wall temperature,and different insulation conditions on the freezing temperature field,the single factor analysis and the multi-factor orthogonal experiment analysis are carried out,and the influence law of each single factor on the development of freezing temperature field and the degree of influence of each factor on the development law of freezing temperature field are obtained.On the basis of this research,the study obtained the development law of freezing temperature field under the typical parameters of frozen steel pipe slices and the development law of freezing temperature field at the interface of frozen concrete pipe slices and soil under the superimposed freezing action of the horizontal freezing pipe in the soil.Then,based on the theory of similarity,physical simulation experiments were carried out,and the freezing temperature field model test at the interface between frozen concrete segments and soil was carried out,and the development law of the freezing temperature field was obtained,and the fitting formula is obtained according to the freezing wall thickness and the average temperature development curve.Finally,the data obtained by numerical simulation and the data obtained by physical simulation are comprehensively compared and analyzed,and the similarities and differences of the freezing temperature field development law between the frozen concrete segment and the frozen steel pipe segment under the numerical simulation are compared,and the horizontal frozen pipe is considered.The similarities and differences in the development of the freezing temperature field between the superimposed freezing effect and the frozen concrete segment freezing separately,and the numerical simulation results of the frozen concrete segments and the model test results are compared and analyzed.The research content of this paper can provide reference for the future treatment of the weak surface at the interface between frozen soil and segment of the connecting channel constructed by the freezing method and the engineering application of this new type of tunnel segment with freezing function.The paper has 155 pictures,14 tables,and 71 references. |
