Microspheres for Shield grouting material - Yanheal 380

In shield tunnel construction, the construction gap between the tunnel segments and the surrounding rock must be grouted to ensure early stability of the segments and connection with the surrounding rock. This helps control the tunnel excavation direction and ensures the final stability of the tunnel. After simultaneous grouting, the grout settles below the segments, and some grout is carried away by the circulating grout. Therefore, unfilled spaces remain in the upper part of the tunnel. Secondary grouting is required to fill these unfilled spaces. Using closed-cell perlite as a lightweight aggregate for secondary grouting perfectly solves this problem.