Development and infiltration behavior of environmental polymer slurry for slurry shield tunneling

With the promotion of the green development and low carbon concept, there is a need to find more efficient, degradable and eco-friendly alternatives to slurry. In this study, a novel polymer slurry of HPAM slurry was developed, and the microscopic structure of novel polymer slurry and viscosity improving mechanism were revealed through the electrochemical reaction analysis. The basic physical properties were investigated, and a suitable and optimal mixing proportion of the HPAM slurry was determined using orthogonal experiments of 9 factors and 4 levels. Besides, the infiltration tests of novel polymer slurry into saturated sand were carried out using self-developed slurry infiltration device, the results indicated that the novel polymer slurry can form a flat and dense filter cake and short infiltration zone, and has the advantages of fast filter cake forming rate, high filter cake quality and excellent support effect compared to the traditional bentonite slurry, indicating the excellent air-tightness and pressure maintaining performances of novel polymer slurry. Meanwhile, the novel polymer slurry can reduce the amount of bentonite used by 67 %. This is attributed to the fact that the new polymer slurry can fully fill the pores between the sand particles in the stratum, establishing a spatial network structure between the sand particles, which indicated the engineering applicability of this slurry. The findings in this paper could offer guidance for the preparation and selection of the eco-friendly slurry used in slurry shield in the future.