Development and performance evaluation of a novel anti-friction agent for H-beam extraction in soil mixing walls

Abstract

This study focuses on the development and assessment of an innovative anti-friction agent designed to reduce the extraction force required for H-beams in Soil Mixing Walls (SMW). The composition of the new formula for the anti-friction agent was determined using orthogonal experimental methods: vaseline (25 g), paraffin (300 g), rosin (65 g), polytetrafluoroethylene powder (9.75 g), ZDDP (10 g), benzoic acid (4 g), ammonium polyphosphate (2 g), alcohol ester-12 (1.5 g), and theaflavin (1.5 g). Performance evaluation of the new anti-friction agent is carried out through indoor model tests, on-site tests, and indoor bending experiments. The results indicate that compared to commonly used anti-wear agents in the field (Nanjing site anti-friction agent, Guangzhou site anti-wear agent), the new anti-wear agent can significantly reduce friction, by 16.4 % and 14.2 % respectively. The new material has little impact on the bending performance of composite structures before cement-soil failure, in contrast to the Nanjing anti-friction agent typically used in field applications. During on-site applications, if the H-beam coated with conventional anti-friction agent cannot be pulled out while the H-beamcoated with the new anti-friction agent can, then the cost of piles treated with the new anti-friction agent is reduced by 97 %. If both types of steel coated with anti-friction agents can be pulled out, then the cost of piles treated with the new anti-friction agent increases by 0.9 %.