An Attempt to Predict the Failure Time of Abandoned Mine Pillars

Castellanza, Riccardo; Gerolymatou, Eleni; Nova, Roberto

doi:10.1007/s00603-007-0142-y

Cited by 45 publications

(24 citation statements)

References 16 publications

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“…While advanced constitute relationships for calcarenites are now well established (Ciantia and di Prisco 2015), realistic hydrochemical weathering scenarios for underground cavities such as the ones reported by Ghabezloo and Pouya (2006) are harder to validate due to complexity of the processes involved. Nevertheless, in the absence of in situ experimental data on the hydro-chemical initial and boundary conditions, one may assume worst-case scenarios, that would in any case result more realistic than a classical stability analysis trough simultaneous homogenous strength reduction in all the whole domains (Castellanza et al 2008). Temporal evolution of surface settlements are then used to determine the corresponding evolution of horizontal strain and angular distortion at the base of the building used to employ the well-known Boscardin and Cording abacus and to calculate BDI(t) that, referring to Fig.…”

Section: A Time-evolving Building Damage Index Bdi(t)mentioning

confidence: 99%

“…12a). The experimental test simulates the degradation processes that might occur in a rock pillar within an underground cavity, when the rock is first soaked by water and then subjected to chemical weathering (Castellanza et al 2008). As the applied vertical stress is smaller than the saturated strength of the calcarenite, the STD will not induce failure, whereas similar experiments where the pillar failure is induced by STD are reported in Ciantia et al (2015b).…”

Section: Bvp#2: Std and Ltd Processes Inducing Model Pillar Failurementioning

confidence: 99%

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

2018

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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

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Section: A Time-evolving Building Damage Index Bdi(t)mentioning

confidence: 99%

Section: Bvp#2: Std and Ltd Processes Inducing Model Pillar Failurementioning

confidence: 99%

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

2018

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“…He returns to this mechanism in the case of loess, where water from external reservoirs is listed as removing soluble binders destroying intergranular bond(s), with the same macroscopic effect of a decreasing cohesion. Sensitivity of basic mechanical soil properties to chemical processes in the environment has been seen to become a critical factor of stability of slopes and coastal structures for a variety of reasons, from periodic changes in salinity of pore water affecting clay behavior of coastal slopes 2,3 to oxidation and dissolution of sandstone, 4 to dissolution of calcite, 5 dissolution of silica in aging sediments, 6 dissolution of gypsum in abandoned mines, 7 to mention just a few examples. In a more modern day context one needs to add that the dissolution of cementation bonds indicated by Terzaghi 1 may be montmorillonite-illite mixtures were transformed into montmorillonite associated with a strength change, including a 30% drop in shear strength.…”

Section: Introductionmentioning

confidence: 99%

A micro-scale inspired chemo-mechanical model of bonded geomaterials

Gajo

Cecinato

Hueckel

2015

International Journal of Rock Mechanics and Mining Sciences

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a b s t r a c tChemical processes influence the mechanical properties of geomaterials, resulting in either strengthening or weakening effects, the latter being particularly critical for long-term safety assessment in civil and energy engineering. Coupling of chemical and mechanical processes in cemented soils and rocks is investigated starting form a micro-structural chemo-mechanical model. The model consists of an assembly of grains and bonds undergoing dissolution or precipitation of mineral mass, affecting geometrical characteristics of the assembly. The principal such characteristics are the evolution of specific surface area and of bond cross-sectional area at the micro-scale, and of porosity at the macro-scale, which become key variables linking the micro-scale and macro-scale mechanisms. This framework has the advantage of avoiding unphysical situations, such as the occurrence of mineral precipitation with no pore space available or the occurrence of dissolution with no cementing material left. The evolution of important micromechanical quantities, such as the number of active bonds and their cross section is tracked. At the macro-scale, a reactive chemo-plasticity model is combined with a model for bonded geomaterials. The resulting micro-to macro-scale transition, schematically applicable to both materials with reactive grains and bonds and materials with only reacting bonds, is validated against the available experimental evidence, concerning calcarenite with both reactive bonds and grains made of the same mineral. The model is thus shown to provide a flexible framework for a consistent interpretation of experimental loading paths, and can be readily extended to more complex circumstances.

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“…The dissolution of minerals in rock-like materials, for example, may reduce the effective size of mineral pillars [19], or may increase the micro cracks and damages in the material, leading to low-stress material failures [22]. Some mineral partings in coal pillars are more sensitive to water and will peel from the pillar, reducing the pillar size [18].…”

Section: Introductionmentioning

confidence: 99%

“…Studies on the long-term stability of mineral pillars showed that, over time, weathering and stress will eventually result in pillar size reduction and pillar strength degradation [18][19][20][21]. The dissolution of minerals in rock-like materials, for example, may reduce the effective size of mineral pillars [19], or may increase the micro cracks and damages in the material, leading to low-stress material failures [22].…”

Section: Introductionmentioning

confidence: 99%

Long-Term Stability Evaluation and Pillar Design Criterion for Room-and-Pillar Mines

Chen

Deng

et al. 2017

Energies

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Abstract:The collapse of abandoned room-and-pillar mines is often violent and unpredictable. Safety concerns often resulted in mine closures with no post-mining stability evaluations. As a result, large amounts of land resources over room-and-pillar mines are wasted. This paper attempts to establish an understanding of the long-term stability issues of goafs (abandoned mines). Considering progressive pillar failures and the effect of single pillar failure on surrounding pillars, this paper proposes a pillar peeling model to evaluate the long-term stability of coal mines and the associated criteria for evaluating the long-term stability of room-and-pillar mines. The validity of the peeling model was verified by numerical simulation, and field data from 500 pillar cases from China, South Africa, and India. It is found that the damage level of pillar peeling is affected by the peel angle and pillar height and is controlled by the pillar width-height ratio.

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An Attempt to Predict the Failure Time of Abandoned Mine Pillars

Cited by 45 publications

References 16 publications

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

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

A micro-scale inspired chemo-mechanical model of bonded geomaterials

Long-Term Stability Evaluation and Pillar Design Criterion for Room-and-Pillar Mines

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