Preparation and use of new green underwater coagulation grouting materials based on NSGA-II algorithm-A case study

Abstract

Karst geology can easily cause various adverse disasters, posing serious safety risks to tunnel construction and operation. In order to treat and fill karst caves, a new type of green underwater coagulation grouting material (GUCG) was developed in this paper. The grouting material uses shield tunneling mud as the basic material, and additives are selected according to the filling requirements of karst caves. Multiple regression analysis is conducted through preliminary mix design, experiments, and strength testing to evaluate the influence of each component of the additives on the strength of the new material. Then, the second generation non dominated sorting genetic algorithm (NSGA-II) was used to optimize the mix proportion of grouting materials, and the results showed that it has good strength and fluidity. Through large-scale underwater karst cave filling model experiments, it was found that the isolation layer formed by GUCG grouting can effectively block the contact between the lower layer of GUCG and water, maintaining the non dispersibility of the material. At the same time, the cementitious material of the isolation layer is not easily affected by water flow, which can effectively maintain the cohesion and fluidity of GUCG materials. Finally, based on engineering experience, a standardized construction process flow for GUCG was developed on site, which has been proven to have good economic efficiency in practice. Based on the above analysis, it can be concluded that GUCG is a safe, economical, fast, and environmentally friendly new material with good application prospects.