A 3D Numerical Approach to Assess the Temporal Evolution of Settlement Damage to Buildings on Cavities Subject to Weathering

Abstract

The goal of this paper is to show how a recently developed advanced chemo-hydro-mechanical (CHM)-coupled constitutive and numerical model for soft rocks can be applied to predict the temporal evolution of settlement damage to buildings on cavities subject to weathering. In particular, a Building Damage Index (BDI) and its evolution with time is proposed. The definition of the BDI is inspired by the work of Boscardin and Cording (J Geotech Eng 115:1-21, 1989) and uses the surface differential settlements obtained by finite element (FE) analyses to assess how far a building is from a non-acceptable service condition. By modelling the reactive transport of chemical species in 3D and using a coupled CHM constitutive and numerical model, it is possible to simulate weathering scenarios and monitor the temporal evolution of surface settlements making the BDI time dependent. This approach is applied to evaluate the damage evolution of two buildings lying on two anthropic caves in a calcarenite deposit belonging to the Calcarenite di Gravina Formation. Standard and advanced experimental tests are performed on the in situ material, and the results are used to calibrate the constitutive model. The soundness of both constitutive relationship and reactive transport solver is subsequently tested by simulating two laboratory-scale boundary value experiments. The first is a model footing test on dry and wet calcarenite, while the second is a small-scale pillar that, after the saturation-induced short-term water weakening, fails due to a long-term dissolution weathering process. Finally, both 2D and 3D coupled FE analyses simulating different weathering scenarios and corresponding settlements affecting the buildings above the considered cavities are presented. Particular attention is placed on assessing the BDI and its temporal evolution. Keywords

A stable mesh-independent approach for numerical modelling of structured soils at large strains

“…In the two cases with highest permeabilities, a punching-type failure mechanism appears. In the plastic bulb beneath the footing the material structure is completely degraded (the variable p t is much lower than the initial one), whereas all the rest of the soil mass remains in intact conditions; qualitatively, this in accordance with physical evidences for circular footings in soft highly porous rocks (Ciantia et al, 2018;Ciantia, 2018) The remeshing routines employed maintain a coarse mesh in most areas in elastic regime but decrease the element size in zones with plastic shearing. The remeshing is clearly visible in Figure 13, where the finite element mesh at the end of penetration is represented.…”

“…These models can represent the behavior of soft rocks (e.g. Lagioia and Nova, 1995;Ciantia and di Prisco, 2016;Ciantia et al, 2018), natural clays (e.g. Wheeler et al, 2003) or artificially cemented soils (e.g.…”

Editorial

“…For example, the separation of the tunnels under Berwick Street induced the formation of three hogging zones and consequent potential to cause a high level of damage to the properties (Figure 1). As detailed by Ciantia et al (2018) and Giardina et al (2019), synthetic aperture radar interferometry shows potential to augment in situ monitoring of building deformations.…”

Theory and Implementation of Constitutive Models for Geomaterials

“…The third set of parameters (ω, p t0 , B d , R) is used to model the mechanical degradation. Calibration of these parameters is made along post-peak (softening) response, taking into account all the considerations made by Nova and coworkers (Lagioia and Nova, 1995;Navarro et al, 2010;Rios et al, 2016;Ciantia et al, 2018).…”