Abstract: Mud film forming support is an important protection method in the construction process of shield belt pressing and opening, etc. The supporting effect mainly depends on slurry materials. In order to effectively utilize the natural red layer weathered soil as raw material for mud film formation, and reduce the cost of artificial materials and reduce its negative impact on the environment, we independently developed a fully transparent and high-pressure filter cake airtightness test device by taking the natural red layer weathered soil as materials and drawing lessons from the process of mud film formation. The Orthogonal tests of mud film formation and airtightness of weathered soil are carried out.without adding any other materials. The mud film forming mode, impact factors, evaluation on application effect, formation time and damage criterion of red layer weathered soil are studied. The results show that the airtight properties of filter cake made from the weathered soil of red-bed are similar to that of common artificial bentonite slurry materials. The application feasibility and reliability of mud film formation using red layer weathered soil are preliminarily verified. It is helpful to promote the development of low-cost, green film-forming technology to provide new support for film formation construction technology.

Key words: red layer weathered soil, film formation, airtightness test, optimum ratio, experimental study