Similarity analysis and verification of slurry fracturing on shield tunnel face using centrifugal modeling

The geotechnical centrifuge test can restore the real stress field in the small-scale model, and provides an effective research method for investigating the slurry fracturing phenomenon of the shield tunnel face. There are several factors involved in shield slurry fracturing include the interaction between soil, slurry, tunnel and other factors, especially the existence of various fluids makes the dimensional analysis, test parameter scaling and data interpretation more complicated in the model test. How to determine a reasonable similar ratio is the key prerequisite for the success of the centrifugal model test. In this paper, on the basis of elucidating the basic physical process of slurry fracturing of shield tunnel face, a model test similarity analysis method based on dimensionless numbers is proposed. The similarity test design system of "tunnel-soil-slurry" based on Butterfield dimensional analysis method was established to apply to geotechnical centrifuges for simulating shield slurry fracturing. This system guarantees the similarity between the model system and the prototype system in terms of size, material, dimensionless number, time, etc., so that the real physical process of shield slurry fracturing can be accurately restored. Finally, the similarity criterion proposed in this paper is further verified by carrying out the slurry fracturing centrifuge model test of the shield excavation face. The research results have certain reference significance for the similarity analysis of the physical simulation of slurry fracturing.