Integrated Model for Ground-Shock Response with EOS, Pore-Crush, Strength, and Damage

Core Concepts

The author presents an integrated model combining EOS, pore-crush, strength, and damage to simulate near-field ground-shock responses efficiently.

Abstract

An integrated model combining Equation of State (EOS) with strength/pore-crush/damage models is developed for near-field ground-shock responses. The model addresses the nonlinear pressure-dependence of strength and the effect of air-filled porosity crushing out. Significant advancements in geomaterial EOS and geomechanical models are discussed. The Yp-Cap model is introduced to integrate EOS for saturated porous rock with pressure-dependent yield, pore-crushing, and damage. The study includes numerical simulations exemplifying the robustness and utility of the material model in underground explosions. Calibration to the Non-Proliferation Experiment (NPE) is conducted to demonstrate the model's capability in finite element simulations.

Stats

"The NPE source consisted of 1.29×106 kg of ANFO-emulsion blasting agent."
"Estimated TNT equivalent energy of 1.07 kiloton."
"Initial density: 1608.80 kg/m3 (Material point), 1910.25 kg/m3 (NPE)."
"Initial shear modulus: 4.557 GPa (Material point), 3.972 GPa (NPE)."
"Exponential hardening coefficient βmax: 0.50 MPa (Material point), 2.0 MPa (NPE)."

Quotes

"The Yp-Cap yield surface is a single surface composed of two other yield surfaces."
"The merging of the two surfaces allows damage from pore-crush while hardening under high-pressure shock loading."

Key Insights Distilled From

An integrated EOS, pore-crush, strength and damage model framework for near-field ground-shock

by Kane C. Benn... at arxiv.org 03-08-2024

https://arxiv.org/pdf/2312.12577.pdf

Deeper Inquiries

How does the integration of EOS with pore-crush modeling enhance ground-shock simulations?

The integration of Equation of State (EOS) with pore-crush modeling enhances ground-shock simulations by providing a more comprehensive and accurate representation of the material response to explosive loading. The EOS captures the nonlinear pressure, density, and temperature relations of geomaterials near the source, while incorporating strength, plastic yielding, and damage mechanisms that are evident in near-field ground-shock responses. By coupling EOS with pressure-dependent plastic yield and damage models, the integrated framework allows for a more realistic simulation of large deformations and pressures experienced during ground shocks.
Pore-crush modeling within this integrated framework accounts for the crush-out effect on air-filled voids as a result of high-pressure loading. This phenomenon is crucial in capturing how air-filled porosity crushes under compaction during shock events. By including pore-crush effects in the model, it becomes possible to simulate partially saturated ground-shock responses where only air-filled voids crush out. This level of detail improves the accuracy and realism of simulations by considering all relevant factors influencing material behavior under dynamic loading conditions.

What are the implications of neglecting pore-crush phenomena in modeling near-field ground-shock responses?

Neglecting pore-crush phenomena in modeling near-field ground-shock responses can lead to significant inaccuracies and limitations in predicting material behavior under explosive loading conditions. Some key implications include:

Inaccurate Strength Predictions: Pore-crush significantly affects strength degradation due to compaction during shock events. Neglecting this phenomenon can result in overestimation or underestimation of material strength, leading to inaccurate predictions of deformation patterns and failure modes.

Incomplete Damage Assessment: Pore-crushing contributes to damage accumulation within materials subjected to high-pressure loads. Ignoring this aspect can lead to incomplete assessments of structural integrity, potentially overlooking critical areas prone to failure or collapse.

Limited Realism: Without accounting for pore-crushing effects, simulations may lack realism and fail to capture essential aspects of material response during ground shocks. This could hinder efforts to optimize designs for blast resistance or assess potential risks accurately.

4 .Reduced Model Robustness: Neglecting pore-crusheffects may limit model robustness when simulating complex scenarios involving varying degreesof saturation or porosity distribution within geomaterials.

How can this integrated model be appliedto other geomechanical scenarios beyond underground explosions?

This integrated model framework can be appliedto various geomechanical scenarios beyond underground explosions by adapting itsto different loadingsituationsandmaterial properties.Hereare some examplesof its applications:
1 .Seismic Events: The modelcanbe usedto simulate seismic waves' propagation through different typesof geological formations,taking into accountthe nonlinearityof thematerialresponseunderhighpressureandlarge deformations.Thiscanhelpin studyinggroundshakings,effectsof earthquakes,andseismic hazard assessment.
2 .Mining Activities: In mining operations,thismodelcanbeutilizedtopredictthegroundresponse todifferentblastingtechniquesor excavationactivities.TheincorporationofsaturatedEOSwithstrengthanddamagemodelsallowsforcomprehensiveanalysisofthematerialbehaviorinducedbymining-inducedstressors.
3 .Geotechnical Engineering: For geotechnical engineeringapplications,suchasfoundationdesignor tunnel construction,theintegratedmodelcancapturethesite-specificgeologicalconditionsandsimulatetheeffectsofdynamicloadingontheinfrastructures.Thiscanaidinassessingstability,riskmanagement,andoptimizingdesignparametersbasedonrealisticmaterialresponses.
4 .Natural Disasters: Theframeworkcanalsobeappliedtosimulategroundresponsesduringnaturaldisasterssuchaslandslidesorvolcaniceruptions.Byconsideringeospatialvariationsinporosity,density,andstrengthproperties,itallowspredictionsofdeformationpatterns,damageextent,andriskassessmentinthepresenceofcatastrophicevents.