Study On Formation Process And Influence Factor Of Frozen Temperature Field In Deep Clay Layer

Since China applied the artificial freezing method for the first time in Kailuan Linxifeng well in 1955,the freezing method has been widely used in many coal fields as a special method for effectively crossing deep topsoil and drilling wellbore in loose aquifers.At present,for the deep topsoil over 450 m,there is still no theoretical guidance for the design of the frozen wall strength,the frozen wall is mainly studied by field measurement and numerical simulation.In this paper,the field test data and FLAC3D software numerieal simulation comparison verification method are used to study the development process of the freezing wall temperature field of the frozen tube with or without deflection conditions and the influence of different factors.The results show that the measured values of the measured temperature and the simulated value are basically the same as the freezing time,which is approximately logarithmic,and eventually stabilizes,the deflection of the freezing tube has a greater influence on the temperature of the temperature measuring hole,and the spacing is reduced,the temperature of the small temperature measuring hole is lowered,and the distance between the rows is increased;the time interval of the frozen wall intersection is the middle circle hole,the outer ring hole and the inner ring hole,the numerical simulation does not consider the influence of the hydraulic field and the heat exchange with the outer boundary,when the freezing pipe is not skewed,the simulated value of the frozen wall intersection time is slightly smaller than the measured value,when the freezing pipe is skewed,the freezing wall crossing time is extended one to two weeks when there is no skewing,the influence of the freezing pipe deflection on the frozen wall crossing time is better big;the simulated value of the average temperature of the frozen wall is basically the same as that of the measured value,when the freezing pipe is not skewed,the average temperature of the frozen wall is slightly smaller than that of the frozen pipe,the maximum difference is 0.88“C,the influence of the deflection of the freezing pipe on the average temperatxire of the frozen wall smaller;when the freezing pipe is unbiased,the freezing front expansion speed is relatively uniform,and the formation process of the freezing wall is relatively regular,when the freezing pipe is skewed,the difference in the expansion speed of the frozen front is different,and the formation process of the frozen wall is disordered,forming a closed unfrozen pressurized water tank of different sizes;the effective thickness of the frozen wall has a large different in the circumferential distribution,and the difference is 0,83 m,the deflection of the freezing pipe has a great influence on the effective thickness of the frozen wall in different directions;the measured value of well temperature is-2.0??-4.0 ?,the simulated value is uniform at-4.5 when the freezing pipe is not skewed,and the circumferential temperature distribution is uneven when the freezing pipe is skewed,the difference is large,the highest temperature is-2.92?,the lowest temperature is-7.12?,the difference is 4.2 ?,the average temperature is-4.13?,the deflection of the freezing pipe has little effect on the average temperature of the well,and has a great influence on the circumferential temperature,there is a relatively weak area along the circumferential direction,and the freezing pipe deflection should be avoided during the construction process;the effect on the freezing effect is the salt water temperature,the initial temperature of the soil,the thermal conductivity,the specific heat,the lower the brine temperature and the initial temperatUre of the soil,the higher the thermal conductivity,and the smaller the specific heat,the better the freezing efFect.Figure[52]table[17]reference[77]...