Abstract

A three-dimensional (3D) discrete element method (DEM)-based numerical model is used to simulate the macromechanical response of sand strengthened using microbially induced carbonate precipitation (MICP) under undrained triaxial compression and inform the particle-scale mechanisms responsible for the behavior. The constant volume method is used to simulate saturated media. Although simulations using rigid boundaries are capable of representing the response of uncemented sands, virtual undrained triaxial tests on cemented sands require the use of flexible boundaries. Flexible membrane boundaries are created using particle facets (PFacets) as the building blocks. A methodology to implement virtual undrained triaxial compression using PFacet-based membrane boundaries is developed. The macroscale response of sands with varying degrees of cementation is adequately captured by this model. A cohesive bond strength, used to express the degree of cementation, is found to be well related to the shear-wave velocity through the soil sample. The model correctly predicts the occurrence of strain localization in cemented media, and the expected trends in shear band formation. The evolution of normal contact force distributions and coordination numbers as functions of both the cementation level and axial strain are also predicted.

Original languageEnglish (US)
Article number04019009
JournalInternational Journal of Geomechanics
Volume19
Issue number4
DOIs
StatePublished - Apr 1 2019

Fingerprint

discrete element method
cementation
compression
sand
shear stress
simulation
membrane
saturated medium
shear band
triaxial test
methodology
strength (mechanics)
carbonates
wave velocity
S-wave
soil sampling
carbonate
particle
soil
testing

Keywords

  • Coordination number
  • Discrete element method (DEM)
  • Force chains
  • Microbially induced carbonate precipitation (MICP)
  • Shear bands
  • Undrained triaxial compression

ASJC Scopus subject areas

  • Soil Science

Cite this

@article{9c695c44970d4c17aed4351afdd347b0,
title = "Particle-scale mechanisms in undrained triaxial compression of biocemented sands: Insights from 3D DEM simulations with flexible boundary",
abstract = "A three-dimensional (3D) discrete element method (DEM)-based numerical model is used to simulate the macromechanical response of sand strengthened using microbially induced carbonate precipitation (MICP) under undrained triaxial compression and inform the particle-scale mechanisms responsible for the behavior. The constant volume method is used to simulate saturated media. Although simulations using rigid boundaries are capable of representing the response of uncemented sands, virtual undrained triaxial tests on cemented sands require the use of flexible boundaries. Flexible membrane boundaries are created using particle facets (PFacets) as the building blocks. A methodology to implement virtual undrained triaxial compression using PFacet-based membrane boundaries is developed. The macroscale response of sands with varying degrees of cementation is adequately captured by this model. A cohesive bond strength, used to express the degree of cementation, is found to be well related to the shear-wave velocity through the soil sample. The model correctly predicts the occurrence of strain localization in cemented media, and the expected trends in shear band formation. The evolution of normal contact force distributions and coordination numbers as functions of both the cementation level and axial strain are also predicted.",
keywords = "Coordination number, Discrete element method (DEM), Force chains, Microbially induced carbonate precipitation (MICP), Shear bands, Undrained triaxial compression",
author = "Pu Yang and Edward Kavazanjian and Narayanan Neithalath",
year = "2019",
month = "4",
day = "1",
doi = "10.1061/(ASCE)GM.1943-5622.0001346",
language = "English (US)",
volume = "19",
journal = "International Journal of Geomechanics",
issn = "1532-3641",
publisher = "American Society of Civil Engineers (ASCE)",
number = "4",

}

TY - JOUR

T1 - Particle-scale mechanisms in undrained triaxial compression of biocemented sands

T2 - Insights from 3D DEM simulations with flexible boundary

AU - Yang, Pu

AU - Kavazanjian, Edward

AU - Neithalath, Narayanan

PY - 2019/4/1

Y1 - 2019/4/1

N2 - A three-dimensional (3D) discrete element method (DEM)-based numerical model is used to simulate the macromechanical response of sand strengthened using microbially induced carbonate precipitation (MICP) under undrained triaxial compression and inform the particle-scale mechanisms responsible for the behavior. The constant volume method is used to simulate saturated media. Although simulations using rigid boundaries are capable of representing the response of uncemented sands, virtual undrained triaxial tests on cemented sands require the use of flexible boundaries. Flexible membrane boundaries are created using particle facets (PFacets) as the building blocks. A methodology to implement virtual undrained triaxial compression using PFacet-based membrane boundaries is developed. The macroscale response of sands with varying degrees of cementation is adequately captured by this model. A cohesive bond strength, used to express the degree of cementation, is found to be well related to the shear-wave velocity through the soil sample. The model correctly predicts the occurrence of strain localization in cemented media, and the expected trends in shear band formation. The evolution of normal contact force distributions and coordination numbers as functions of both the cementation level and axial strain are also predicted.

AB - A three-dimensional (3D) discrete element method (DEM)-based numerical model is used to simulate the macromechanical response of sand strengthened using microbially induced carbonate precipitation (MICP) under undrained triaxial compression and inform the particle-scale mechanisms responsible for the behavior. The constant volume method is used to simulate saturated media. Although simulations using rigid boundaries are capable of representing the response of uncemented sands, virtual undrained triaxial tests on cemented sands require the use of flexible boundaries. Flexible membrane boundaries are created using particle facets (PFacets) as the building blocks. A methodology to implement virtual undrained triaxial compression using PFacet-based membrane boundaries is developed. The macroscale response of sands with varying degrees of cementation is adequately captured by this model. A cohesive bond strength, used to express the degree of cementation, is found to be well related to the shear-wave velocity through the soil sample. The model correctly predicts the occurrence of strain localization in cemented media, and the expected trends in shear band formation. The evolution of normal contact force distributions and coordination numbers as functions of both the cementation level and axial strain are also predicted.

KW - Coordination number

KW - Discrete element method (DEM)

KW - Force chains

KW - Microbially induced carbonate precipitation (MICP)

KW - Shear bands

KW - Undrained triaxial compression

UR - http://www.scopus.com/inward/record.url?scp=85060136685&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85060136685&partnerID=8YFLogxK

U2 - 10.1061/(ASCE)GM.1943-5622.0001346

DO - 10.1061/(ASCE)GM.1943-5622.0001346

M3 - Article

VL - 19

JO - International Journal of Geomechanics

JF - International Journal of Geomechanics

SN - 1532-3641

IS - 4

M1 - 04019009

ER -