Structural test at the laboratory scale for the utilization of stabilized fine-grained soils in the subgrades of High Speed Rail infrastructures: Analytical and numerical aspects

• The stress states in the capping layer of several HSRs structures have been modeled.
• Results are compared with stress paths induced by several laboratory fatigue tests.
• A test is highlighted and a design dedicated to treated/stabilized soils is proposed.

The utilization of insitu fine-grained soils treated with lime and/or hydraulic binders as subgrade in common infrastructures of civil engineering is a sustainable upgrading process for natural materials with low mechanical performances. In the case of the projects of High Speed Rail (HSR), the expected life of structures and the stresses caused by traffic have led to ask about the fatigue mechanical behavior of these stabilized materials. Therefore, for the design of HSR structures, a characterization of these performances must be defined with a suitable test. Fatigue tests referenced from the literature are studied in comparing the stress paths induced by these tests with those obtained in the HSR capping layer. An appropriate fatigue test for the design of HSR structures is presented and the dimensions of the test-pieces are validated using Finite Element Method (FEM).