Instant detection method of grouting effect in deep mine goaf

In order to obtain the grouting effect and dynamically evaluate the treatment quality in the process of founda⁃ tion filling treatment of mine goaf，the grouting effect instant inspection method was studied for a deep strip mined out area in Jining，China.The multi⁃coefficient method was proposed to quantitatively and timely detect the grouting effect. Combined with the drilling and grouting data in the construction process，four coefficient indexes were given，and the index evaluation standard was determined.The results show that the larger the attenuation coefficient s of grouting a⁃ mount in the later sequence drilling，the worse the injectability of the goaf stratum is，the better the grouting filling effect is.The attenuation coefficient of grouting amount in sequence II should not be lower than 0.3，and that in se⁃ quence III should not be lower than 0.9.The larger the downward coefficient l of the total leakage height of circulating fluid in the subsequent drilling holes is，the smaller the residual void ratio of the grouting target layer in goaf is，and the better the grouting filling effect is. The total leakage height downward coefficient of the second sequence drilling should not be less than 0.15，and the downward coefficient of the total leakage height of the third se⁃ quence drilling should not be less than 0.20.The smaller the difference coefficient c of grouting amount in each grou⁃ ting unit，the lower the risk of weak grouting area and the better the grouting filling effect.The coefficient of difference should not exceed ± 0.15.The smaller the dispersion coefficient δ of grouting amount in the same drilling sequence in⁃ dicates that the better the grouting process control effect and the higher the grouting filling quality.The dispersion coef⁃ ficient should not exceed 1.2.The reliability of the multi⁃coefficient index method is verified by the quality inspection after construction.The multi⁃coefficient index method is combined with each other and the detection results of each in⁃ dex are verified each other，which accurately reflects the grouting effect in the construction process.Using the instant analysis results，the grouting technology and its parameters can be dynamically optimized and adjusted in the process of grouting construction，so as to strengthen the process quality control of grouting construction and improve the quality of grouting treatment.