Influence of key parameters of cyclic loading on the behaviour of chemically stabilized soil unreinforced and reinforced with fibres

Abstract

In this work the effect of the number of cyclic loads on the mechanical behaviour of a chemically stabilised soft soil, reinforced with synthetic polypropylene fibres, and not reinforced, are analysed. This experimental study was carried out on a Portuguese soft soil collected in the Baixo Mondego area in the centre of the country. The laboratory work is based on the following tests: i) monotonic unconfined compression test (UCS), ii) cyclic unconfined compression test performed with different numbers of cycles (2500, 5000, 10000) and several frequencies (0.25, 0.5, 1.0, 2.0 Hz) for a load corresponding to 50% of the strength evaluated in the monotonic tests (UCS) and iii) monotonic UCS tests performed after the cyclic loading stage (UCSpc). The analysis is complemented with the study of the accumulated permanent axial deformation developed during the cyclic stage. The results show that the accumulated permanent  axial strain increases with the number of cycles, also the strength and stiffness after the cyclic loading stage increase their values.