New soil abrasion testing method for soft ground tunneling applications

► Soil abrasion has a major impact on soft ground mechanized tunneling but not well quantified in contract documents and source of delays and claims. ► Previous soil abrasion tests are reviewed and initial steps for developing a new soil abrasion index are discussed. ► The preliminary results of testing on various soils have been presented and showed a promise for future application in soft ground tunneling. Prediction of the tool wear and life, as well as secondary wear on machine components, in soft ground tunneling using shielded machines with a pressurized face has been a difficult task due to the lack of a universally accepted measurement system for soil abrasion. While some existing abrasion tests have been adopted in recent years to measure soil abrasion, these systems have inherent mismatches with the actual working conditions at the tunnel face. This paper reviews some of the background studies in this area and introduces the initial steps towards the development of a new soil abrasion testing system. The design and operational parameters for a proposed device that is under development for measuring a soil abrasion index are discussed and the preliminary results of testing on various soil samples are presented.