Effects of Soil Conditioning on Tool Wear for Earth Pressure Balance Shield Tunneling in Sandy Gravel Based on Laboratory Test

Soil conditioning plays an important role in reducing soil abrasivity and wear of cutting tools in earth pressure balance shield tunneling, leading to service life extension of cutting tools. In this article, an experimental study to assess the abrasivity of conditioned soil with different conditioners, namely foam and slurry, was carried out using a soil abrasion tester. The abrasive characteristics of the tested soil samples were quantitatively assessed through the measurement of weight loss of the steel cubes fixed on the propeller. Preliminary test results indicate that both foam and slurry can modify the sandy gravel to a suitable state according to slump test and decrease soil abrasivity significantly. The torque, which reflects the interaction between the propeller and tested materials, is used to provide insights into the soil-tool contact. Potential relationships between tool wear and tool position are also investigated.