Comparison of Soil Pressure Calculating Methods Based on Terzaghi Model in Different Standards

Abstract

Soil pressure calculation method for Trenchless pipe based on the Terzaghi Soil Arching Theory have been defined in Chinese national standard GB50332-2002, North America standard ASTM F1962-09 and European standard BS EN 1594-2009. At present, the calculation results from all of the three standards have shown discrepancies with the measured soil pressure. There is little research on the issue of discrepancies in each standard based on the same Terzaghi soil arching theory. The comparison has been made to investigate the differences among all the three standards. The conclusions can be made that the calculation in both GB50332 and ASTM F1962 ignores the cohesion and compressibility of the soil, using the same method to calculate sand soil and clay soil, and does not fully consider the effect of the internal friction angle of soils, which lead to a small impact of the soil properties on the arching factor. The BS EN 1594 standard considers the cohesion strength of soils and uses two different methods for pressure of sand soil and clay soil, respectively; The comparisons show that the cohesion strength has a significant impact on soil pressure, and that the former two standards showed a higher soil pressure than BS EN 1594 since both of them ignored the cohesion strength of soils.