Effect of Water Content on the Abrasivity of Granular Soils in Soft Ground Tunneling Applications

摘要

This paper presents an experimental study of tool wear and abrasivity of granular soils using a testing system specifically designed for the evaluation of wear in soft ground tunneling applications. In the testing system, a propeller which is fitted with steel covers with different hardness is rotated at 60 rpm in granular soil samples in a chamber under ambient pressures of up to 10 bar. The developed system can quantitatively assess the abrasive characteristics of soils through the measurement of weight loss on the special covers of the propeller, accounting for soil gradation, mineral composition, sphericity and roundness, water content, and tool hardness. Preliminary test results indicate that water content has significant impact on tool wear and soil abrasion. For the tests conducted, it is observed that tool wear first increases with water content until the water content reaches about 7-10%; beyond this range, higher water content reduces tool wear.