Evaluation of advanced constitutive modelling for cemented clayey soils: A case history

Performance evaluation of a shallow foundation built on structured clays under seismic loading

“…Due to their relatively high compressibility, the two clayey layers play a crucial role in the settlement response of the silo to the applied loads. Previous numerical analyses of the same case study (D'Elia et al 1999;Burghignoli et al 2003) have already demonstrated the importance of using advanced constitutive models to properly describe the mechanical behaviour of the Avezzano cemented clayey soils. Simpler constitutive hypotheses, such as the Modified Cam-Clay (MCC) model (Roscoe and Burland 1968), were found to be unable to successfully capture the main features exhibited by the measured load-settlement curve of the sugar silo under working loads, as shown in Figure 3c.…”

Modelling the transverse behaviour of circular tunnels in structured clayey soils during earthquakes

“…Burghignoli et al [30], [31] and Burghignoli et al [32] for Avezzano Clay, a structured [30,32]. The response of the deposit in Avezzano to cyclic loads imposed by a silo shallow foundation has been investigated in the past by Burghignoli et al [30], et al [33], Burghignoli et al [34] and, more recently, Elia and…”

“…Figure 1 shows the comparison in terms of stress paths, stress-strain and pore pressure-strain response between the laboratory data from [32] and the numerical predictions obtained with RMW. For the same set of experimental data shown in the figure, the constitutive model has been calibrated following the work by [27,34], considering an initial degree of structure r0 equal to 5.2 and two rates of destructuration with damage strain (i.e. two values of the parameter k).…”

“…Figure 3 shows the geometry of the FE model adopted in PLAXIS 2D [28] along with the dynamic boundary conditions. As in previous works [27,34], a coefficient of earth pressure at rest K0 equal to 0.5 has been assumed in the generation of the geostatic stress state, using a unit weight of 18kN/m 3 Brady [43], maximum acceleration (amax) and maximum velocity (vmax). Both input motions have been filtered to prevent frequencies higher than 10Hz and scaled up to the same peak acceleration (PGA) of 0.30g, according to the seismic hazard analysis of the site presented by Elia and Rouainia [27].…”

“…for the clay. The G0 profile resulting from the equation proposed byViggiani and Atkinson [35] is shown in the same figure and compared with RC data on Avezzano Clay presented by Burghignoli et al[34]. The FE model has been discretised with a total number of 5088 15-noded plane strain triangular elements, with the mesh refined in the region around the tunnel to avoid mesh sensitivity due to the softening behaviour predicted by the RMW model.…”