Model test study on efficiency of pressure gas reverse circulation shaft washing in large diameter shaft boring machine
SONG Yang
CHENG Hua
GUO Longhui
RONG Chuanxin
WANG Xiaoyun
Abstract：Aiming at the problem of low efficiency of drilling and washing shaft of shaft drilling sinking in Jurassic strata in western China,taking the central return air shaft drilling sinking in the western China Kekegai Coal Mine as the research background,based on the self-developed pressure gas reverse circulation shaft washing test device,the similar model test of pressure gas reverse circulation shaft washing was carried out.The orthogonal test and range analysis were used to explore the influence of factors such as bit speed,air pressure and air duct embedding coefficient and other factors on the effi-ciency of pressure gas reverse circulation shaft washing,and the parameter combination of efficient shaft washing was put forward.The results show that:① Through the results of orthogonal test and range analysis,the sensitivity order of the main influencing factors of shaft washing efficiency is as follows:bit speed＞air pressure＞air duct embedding coefficient.② Based on the results of the model test,the evaluation indexes of shaft washing efficiency are put forward,which are the debris removal rate and the rock carrying rate.Both of them increase sharply first and then decrease slightly with the increase of bit speed and air pressure,and are positively correlated with the buried coefficient of air duct.③ The displacement of washing fluid is negatively correlated with the rotation speed of the drill bit.The displacement of drilling cuttings increases first and then decreases with the increase of the rotation speed of the drill bit and the air pressure.④ Based on the model test results,the high-ef-ficiency shaft washing parameters are proposed:the bit speed is 8.6 r/min,the air pressure is 1.44 MPa,and the air duct embedding coefficient is 0.837.The research results can provide a useful reference for improving the low efficiency of drilling and shaft washing in Jurassic strata in western China.
Keywords：shaft boring machineshaft drillingpressure gas reverse circulation shaft washingmodel testrange analysis
Publication Date：2024-06-25
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：9( 59-67 )