Research on the Relationship between Soil Shear Stress Level and Safety Factor

Abstract

At present, in the design of geotechnical structures, the allowable bearing capacity is mostly designed according to the safety factor specified in the design specification. However, there are two problems that have not yet been clearly explained in theory: (1) why is the safety factor listed in the standard is suitable for the design of geotechnical structures and (2) can the safety factor selected according to the specification guarantee the long-term stability of soil mass. In view of the above problems, according to the statistical law in the rheological properties of soil, the relationship between the shear stress level of the soil and the stability of the soil is studied, and the stable shear stress level of the soil is obtained. The research results show that the stable shear stress level of soil is the corresponding shear stress level under static earth pressure. This conclusion not only verifies the correctness of the theoretical finding that “the earth pressure on the structure develops toward the static earth pressure, and whether the ultimate safety of the geotechnical structure is related to its design bearing capacity is greater than the static earth pressure” in the design code of the retaining structure but also clarifies the source of the safety factor. By calculating the design bearing capacity of the geotechnical structure according to the static earth pressure, the geotechnical structure that maintains long-term stability can be designed, which provides a reliable method for the design of the permanent geotechnical structure.