Research On Temperature Field And Frost Heaving Stress And Judging Technology In Closure Process Of Inclined Shaft That Freezing Along The Axial

The sealing property of the freezing wall in rich water layer is critical for security of subsequent freezing wall excavation and shaft wall pouring. Once inclined shaft freezing wall is not closed, this maybe cause the gushing-sand and even flooded wells. Whether the frozen wall is closed or and how to determine the closure of the frozen wall is particularly important for inclined shaft,which adopt the scheme of inclined hole freezing. For inclined hole freezing hole’s inclined shaft, decentralization of the freezer and heat convection of saline water is distinguished from the vertical freezing hole, which is bound to cause the changes of freezing temperature field and stress field of frost heave.Therefore, the thesis will carry out research about inclined shaft freezing temperature field and stress field of frost heave by combining methods of numerical simulation and physical experiment. Research findings can provide the basis for the future construction of freezing shaft.Firstly, numerical simulation is carried out. According to the common parameters of inclined shaft, the scheme of freezing hole layout and the three-dimensional inclined shaft model of double coil freezing tube is established.The displacement field, temperature field and frost heaving stress field of the frozen wall under typical parameters are analyzed by setting different thermal strain coefficient to simulating moisture transfer of sand soil.Combined with characteristic point cooling process, the variation characteristics of the frost-heaving stress of feature points have been analyzed. In addition, the influence of moisture content, the depth, the distance between the inner and outer ring and freezing time on freezing wall displacement field and stress field of frost-heave are considered separately.Secondly, according to the similarity criterion,physical simulation experimental research for double-circle freezing pipe’s inclined shaft has been designed. Physical experiment has simulated the formation conditions of the freezing pipe through two sand soil aquifers.In the experiment,the variation laws of the temperature field and freezing-heave stress field in rich water sand layer have also been qualitatively analyzed,which can provide a basis for closure judgement of inclined well of the frozen wall.Finally, by comparing the results of the numerical simulation with the results of physical simulation, the scientific nature of the two kinds of research methods is verified. Combined with the change law of temperature field,frost heaving force,pore water pressure from numerical simulation and physical test before and after the frozen wall sealing,Considering the current method and applicability to judgging closure,puts forward a applicable to frozen frozen wall slope inclined hole closed circle method determination methods, the method of judging the closure of frozen wall of inclined shaft by Inclined hole freezing scheme is put forward.