Research On The Distribution Of Temperature Field Of Froze Shaft Wall With Deep Water-abundant Sandstone Layer In Cretaceous

With the rise of a new wave of construction wells in the western region,a large number of engineering practices have concluded that the artificial freezing method is a special construction method that effectively penetrates the deep rich water-rich bedrock of the Cretaceous.According to a large number of references,although people have mastered some basic physical and mechanical properties of the Cretaceous rocks,they have not systematically studied them in depth,especially regarding the study of the temperature field of the frozen wall of the Cretaceous sandstone layers.In the background of the 910m freezing wind shafting project,the medium-grained sandstone layer at-632m of the Luohe Formation in the Cretaceous was selected as the research object,and the temperature field of the frozen wall before and after excavation,under excavation,and under the influence of hydration heat was systematically studied.The law of change.In terms of theoretical research,the theoretical concepts of temperature field and freezing temperature field are expounded;the main influencing factors of freezing temperature field are discussed;and the basic equations of freezing temperature field are deduced and established on the basis of basic theories of thermodynamics and energy conservation principle.The theory of temperature field model for the wellbore before excavation,after excavation and in the heat affected stage of hydration.In ANSYS numerical simulation,ANSYS software was used to numerically simulate the temperature field of the frozen wall before excavation under single-loop,single-tube freezing,single-loop,and multi-tube freezing,and the obtained different freezing times(ie,8d,30d,83d)were obtained.,148d,204d,256d)under the temperature field change curve and the radial temperature change curve and the temperature change curve from the center of the freezing pipe and the different positions of the well center were analyzed,and the system was summarized in the single ring,the single tube freezing and the single ring The distribution law of the frozen wall temperature field before the excavation was frozen in the multi-tube freezing method,and the changing laws of the frozen front speed and the thickness of the frozen wall with the freezing time were obtained.At the same time,the single-loop,multi-tube frozen excavation was established using the ANSYS software.The numerical simulation model of the temperature field of the outer borehole wall and the frozen wall affected by the hydration heat influence phase passes through the outer layer of the obtained different time(ie,1.5d,3d,10d,67d)after casting the outer wall borehole concrete.The analysis of the temperature field curves of the borehole wall and the frozen wall and the analysis of the radial temperature change curve summarizes the distribution characteristics and interior of the"two-wall" radial temperature field under the influence of heat of hydration under single-loop and multi-tube freezing conditions.Point temperature variation.In terms of on-site measurement,based on the analysis and analysis of on-site monitoring data of temperature of cryogenic brine,temperature of temperature measurement hole in different locations,and radial temperature of frozen wall and outer wall of borehole during freezing and excavation and pouring of concrete in the borehole wall,The system summarizes the changes of the temperature field,thickness,and average temperature of the frozen wall with time,and the law of melting and refreezing of the frozen wall over time before excavation,after excavation and under the influence of hydration heat.Finally,the feasibility of ANSYS numerical simulation was validated by the comparison of temperature simulations and field measurements.