Optimization and application of backfill grouting material for submarine tunnel

The impacts of composition and mixture ratio of backfill grouts on the anti-floating ability and workability cannot be ignored in the submarine tunnel engineering. The orthogonal tests were adopted to design a new hardened cement-lime grouting material (HCLGM) and its physical properties were examined. The results show that the shear strength, density, consistency and bleeding rate of HCLGM are largely influenced by the water-binder ratio while the setting time is mainly affected by the cement-fly ash ratio. The recommended mixture ratio for grouting material was determined by linear regression analysis method which is sand of 16.3%, cement of 6.6%, slaked lime of 13.4%, fly ash of 26.5%, bentonite of 4.8% and water of 32.4%. The proposed HCLGM was used in a practical engineering case and contributed to the antifloating capacity of tunnels. (C) 2020 Elsevier Ltd. All rights reserved.