PCA-KNN-based TBM construction surrounding rock comprehensive grading prediction method

The invention discloses a PCA-KNN-based TBM construction surrounding rock comprehensive grading prediction method, and the method comprises the steps: carrying out the training and learning of a plurality on obtained principal component variables and corresponding comprehensive surrounding rock grades by employing a k-nearest neighbor algorithm, and building a mathematic model of each index-comprehensive surrounding rock grade; extracting principal components from the detection data based on the training data and verifying the accuracy of the established model by using the established mathematical model; and obtaining influence factor index values near an unexcavated tunnel face, carrying out principal component analysis based on the average value, standard deviation and the like of the training data, obtaining corresponding principal components, and then carrying out TBM construction surrounding rock comprehensive grading prediction by using the obtained mathematical model. Accordingto the method, difficulti