Study On Vertical Structural Stability Of Super-deep Bored Shaft Submerged In Slurry

Based on the energy method principle and the object of main shaft and ventilation shaft for Banji mine coal in Anhui province in this thesis, the vertical structural stability of the two bored shaft are analysed and calculated. Moreover,based on the Newmark numerical integration principle, the corresponding program for the stability of shaft is edited, the stability of shaft in different force conditions are explored,and the influence of stability under the righting force imposed on the top of shaft is mainly studied. By the initial engineering practice test,the calculation model,calculation method and calculation results are feasibility in the thesis, some theory references for the practical problem which needs to be urgently solved are provided. The main product are stated below:(1) Based on the investigation of deep bored shaft construction at home and abroad and in combination with the actual practice,considered the shaft as a end lap fixed-top free compressed bar analysing its stability,the results of calculation is closer to the practice.(2) Analysis for the stability of main shaft and ventilation shaft for Banji mine in Anhui province in the paper,the analytical method and Newmark numerical calculation program are used respectively. According to the calculation results,both the main shaft and the ventilation shaft can keep their stability,which are in agreement with the results of field monitoring.(3) Checking calculation for the flexural intensity and rigidity of welding seam between the shaft internode,and then the specific requirements for the thickness and the quality of the welding seam are provided.(4) This thesis discussed the factors which can influence the vertical stability of shaft,then further conclusions are arrived that the shaft's dead weight and balance water are unfavorable to the stability,and the slurry is beneficial to the stability .And what's more, some methods and measures are put forward for maintain the super-deep bored shaft's vertical structural stability. (5) Improving the stability of shaft,we can do it from design and construction. Practice shows that the measures that strengthen the thickness and the quality of welding seam,improved the consistency of slurry,monitored the righting colsely and rectify carefully, cleared the sediment making the bottom of shaft embedded firmly,cemented the shaft with the early-strength cement slurry and so on are efficient for the stability of shaft.