Abstract: To study the effectiveness of the treatment method of soaking mud cake in a dispersant solution and the disintegration characteristics of cutterhead mud cake, undisturbed mud cake from the soft rock portion of the shield section of the Shenzhen railway transit line 13 is made into several samples with different sizes. A laboratory disintegration test is conducted on the mud cake samples under different test conditions using a self-improved disintegrator. The influence of the dispersant solution, solution volume fraction, mud cake site, initial water content, and dry-wet cycle on the disintegration characteristics of the mud cake is analyzed. The test results show the following: (1) Mud cake disintegration mainly goes through three stages, i.e., initiation, development, and stabilization. (2) The effect of the dispersant solution on the mud cake is adaptive in nature and is related to the concentration of the solution. Furthermore, the concentration of the solution on the promotion of the disintegration has a specific threshold. (3) The mud cake scale is related to dispersant treatment. (4) The initial water content of the mud cake has a significant influence on its disintegration characteristics. For mud cake having high moisture content, it is suggested to take necessary measures to reduce the initial water content to 5% or less according to the field application effect. (5) Dry-wet cycle can accelerate the destruction of the internal structure of the mud cake. The difficulty in processing mud cake can be reduced after three iterations of the dry-wet cycle.

Key words: shield cutterhead, mud cake, laboratory disintegration test, dispersant solution, size of mud cake, initial water content, dry-wet cycle