Risk evaluation method for shield clogging based on interface adhesion force

In order to accurately predict the risk of cutterhead clogging and provide the basis for preventing and controlling cutterhead mud cake in the tunneling of high clay stratum, the laboratory tests are conducted by using the self-designed soil-metal interface pull-out test device and the improved direct shear test device. The variation rules of the normal and tangential adhesion forces of different soil samples under different consistency indexes are analyzed through the laboratory tests. Based on the test results, a five-grade shield clogging risk zone map for adhesion force is proposed and used to evaluate the conditioning effects of the strongly weathered mixed granite residue. The results show that the normal adhesion first increases and then decreases with the increase of the consistency index, and the increase of the montmorillonite content decreases the peak line consistency index of the normal adhesion. The friction angle and tangential adhesion of the whole samples remain at a low level when the consistency index is less than 0.6. When the consistency index is greater than 0.6, the tangential adhesion of the pure clay sample increases with the increase of the consistency index, and the tangential adhesion of the sandy soil sample has a peak value near the consistency index of 0.9, and then decreases. The shield clogging risk zone map for adhesion force can reflect the path of the change of shield clogging risk in the process of soil conditioning, and the effects of soil conditioning can be evaluated.