An improved soil abrasion testing method for shield tunnelling based on LCPC

The Labroatoire Central de Ponts et Chaussées (LCPC) test is a commonly used method to test the abrasivity of soil, however, the existing LCPC tests have some shortcomings in evaluating the abrasivity of shield tunnel soil, such as the high effective breakage rate of soil particles and large changes in particle size distribution during testing. In view of this, a circular steel sheet is used to replace the original rectangular steel sheet, and a comparative test is carried out. The test results show that the improved circular steel sheet significantly reduces the effective breakage rate of soil samples compared with the rectangular steel sheet, and improves the stability of particle size distribution in the LCPC test. The wear of the circle steel sheet in the test process is mainly abrasive wear, which effectively eliminates the impact wear and is more in line with the characteristics of shield tunnel engineering. The analysis shows that the conversion relationship between the two LCPC abrasivity coefficients is LAC_矩=0.93LAC_圆 when abrasive wear is the main wear. The improved testing method accurately evaluates the abrasivity of the pebble layer crossed by the shield tunnel sections Youanmen-Niujie of Beijing Subway Line 19 and 3# Fengjing-Caoqiao of the Beijing Daxing International Airport Line. This study improves the accuracy of the LCPC test method in evaluating the soil abrasion of shield tunnel.