Excavation in sand

The example of the excavation is taken over from PLAXIS manual; the problem is simulated with sand hypoplasticity model. Soil parameters of the sand correspond to the Hochstetten sand from Tab. 4.1; the intergranular strain parameters used are in Tab. 4.2. The sand is in a medium dense state with $e_0$=0.85.

Fig. 5.1 shows total displacements. Fig. 5.2 shows the normalised length of the intergranular strain tensor. The normalised length of the intergranular strain tensor varies between 0, which indicates the soil being inside the elastic range, and 1, corresponding to the state swept-out of the small-strain memory. In the case of the normalised length of the intergranular strain being equal to 1 the soil behaviour is governed by the basic hypoplastic model. Indeed, Fig. 5.2 shows that this is the case of an excavation, the soil below the bottom of the excavation and behind the wall is outside the small-strain-stiffness range. Fig. 5.3 shows mobilised friction angle, indicating emerging failure mechanism.

Figure: Excavation in sand - total displacement.

Figure: Excavation in sand - normalised length of the intergranular strain tensor.

Figure: Excavation in sand - mobilised friction angle.

Input file for this example may be downloaded in Sec. 8.