Experiment Study on Proportioning of Similar Materials in Weak Surrounding Rocks of Rich-Water Faults

To optimize the construction scheme of water-rich faults in long tunnels and ensure the safety of construction, mud and water inrush test must be performed. The orthogonal design method is used to perform a proportioning test, and similar materials for the mud and water inrush test are developed. Subsequently, the relationship between material parameters and control factors are quantitatively analyzed using a numerical method. Through range analysis, the influence rule and correlation of each factor on the material parameters are obtained. Through variance and multivariate regression analysis, it is found that the main control factor is crucial for controlling the corresponding parameters. In addition, based on multivariate regression analysis, a new empirical formula (regression model) is fitted and the residual analysis of the obtained model is performed. The results show that the regression model is normal. The maximum relative error of the fitting test data was used to remove the permeability coefficient, except for 16.7554% (< 20%), the remainder were less than 3%. This indicated that the test data were reasonable and the empirical formula reliable. The empirical formula can be used to determine the ratio of similar materials in soft surrounding rocks of water-rich faults quickly.