Abstract:

The soil properties under small strain are tested through advanced stress path triaxial test system (STDTTS+UNSAT) equipped with high precision local displacement tensor. Using three dimensional numerical simulations, the influence of tunneling on traverse settler was studied by the models of small strain and Mohr-Coulomb separately. Some conclusions are drawn. Firstly, there is high modulus of soil under small strain and modulus degrades with the increase of strain. When logarithm coordinates are applied to describe shear strain, the rule of shear modulus decaying with shear strain can be expressed by reversed S-shaped curve with two inflexion points; and the function of the curve is deduced. Secondly, rules of the results by both models are similar. Finally, both the maximum subsidence displacement and the width of traverse settler by using small strain model are accorded with practical project. While there is an incompatible problem by using the common models, that is, only the maximum subsidence displacement or the width of traverse settler is reasonable. The comparative analysis is made to validate the indispensability of small strain consideration, as well as the reasonability and feasibility of the second development model.

Key words: small strain, second development, high modulus, nonlinearity, traverse settler