Back Analysis Procedure for Identification of Anisotropic Elastic Parameters of Overcored Rock Specimens

2016 ◽  
Vol 50 (3) ◽  
pp. 513-527 ◽  
Author(s):  
M. Espada ◽  
L. Lamas
Keyword(s):  
Back Analysis ◽  
Analysis Procedure ◽  
Elastic Parameters ◽  
Anisotropic Elastic ◽  
Rock Specimens

Enabling isotropic reflectivity modeling and inversion in anisotropic media

2021 ◽  
Vol 40 (4) ◽  
pp. 267-276
Author(s):  
Peter Mesdag ◽  
Leonardo Quevedo ◽  
Cătălin Tănase
Keyword(s):  
Synthetic Data ◽  
Anisotropic Media ◽  
Forward Modeling ◽  
Seismic Inversion ◽  
Stratified Medium ◽  
Effective Parameters ◽  
Elastic Parameters ◽  
Pp Wave ◽  
Anisotropic Elastic ◽  
And Inversion

Exploration and development of unconventional reservoirs, where fractures and in-situ stresses play a key role, call for improved characterization workflows. Here, we expand on a previously proposed method that makes use of standard isotropic modeling and inversion techniques in anisotropic media. Based on approximations for PP-wave reflection coefficients in orthorhombic media, we build a set of transforms that map the isotropic elastic parameters used in prestack inversion into effective anisotropic elastic parameters. When used in isotropic forward modeling and inversion, these effective parameters accurately mimic the anisotropic reflectivity behavior of the seismic data, thus closing the loop between well-log data and seismic inversion results in the anisotropic case. We show that modeling and inversion of orthorhombic anisotropic media can be achieved by superimposing effective elastic parameters describing the behavior of a horizontally stratified medium and a set of parallel vertical fractures. The process of sequential forward modeling and postinversion analysis is exemplified using synthetic data.

scholarly journals Determination of anisotropic elastic parameters from morphological parameters of cancellous bone for osteoporotic lumbar spine

2021 ◽  
Author(s):  
Christoph Oefner ◽  
Elena Riemer ◽  
Kerstin Funke ◽  
Michael Werner ◽  
Christoph-Eckhard Heyde ◽  
...  
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Cancellous Bone ◽  
Elastic Constants ◽  
Bone Volume ◽  
Human Bone ◽  
Homogenization Theory ◽  
Elastic Parameters ◽  
Anisotropic Elastic

AbstractIn biomechanics, large finite element models with macroscopic representation of several bones or joints are necessary to analyze implant failure mechanisms. In order to handle large simulation models of human bone, it is crucial to homogenize the trabecular structure regarding the mechanical behavior without losing information about the realistic material properties. Accordingly, morphology and fabric measurements of 60 vertebral cancellous bone samples from three osteoporotic lumbar spines were performed on the basis of X-ray microtomography (μCT) images to determine anisotropic elastic parameters as a function of bone density in the area of pedicle screw anchorage. The fabric tensor was mapped in cubic bone volumes by a 3D mean-intercept-length method. Fabric measurements resulted in a high degree of anisotropy (DA = 0.554). For the Young’s and shear moduli as a function of bone volume fraction (BV/TV, bone volume/total volume), an individually fit function was determined and high correlations were found (97.3 ≤ R2 ≤ 99.1,p < 0.005). The results suggest that the mathematical formulation for the relationship between anisotropic elastic constants and BV/TV is applicable to current μCT data of cancellous bone in the osteoporotic lumbar spine. In combination with the obtained results and findings, the developed routine allows determination of elastic constants of osteoporotic lumbar spine. Based on this, the elastic constants determined using homogenization theory can enable efficient investigation of human bone using finite element analysis (FEA).

Cross-anisotropic elastic parameters of two natural stiff clays

Géotechnique ◽  
2011 ◽  
Vol 61 (9) ◽  
pp. 809-814 ◽  
Author(s):  
S. YIMSIRI ◽  
K. SOGA
Keyword(s):  
Elastic Parameters ◽  
Stiff Clays ◽  
Anisotropic Elastic

Stability Assessment of Silin Powerhouse Cavern Based on Displacement Back Analysis Method

2011 ◽  
Vol 243-249 ◽  
pp. 2478-2482
Author(s):  
Yun Hao Yang ◽  
Chong Shi ◽  
Ling Ran Zhang
Keyword(s):  
Orthogonal Design ◽  
Safety Margin ◽  
Back Analysis ◽  
Analysis Procedure ◽  
Support Vector ◽  
Particle Swarm Optimizer ◽  
Hybrid Optimization Algorithm ◽  
Nonlinear Relation ◽  
Measured Displacement ◽  
The Stability

A back analysis procedure synthetically using parameters sensitivity analysis based on orthogonal design variance analysis, support vector regression modeling of nonlinear relation between mechanical parameters and displacement, and a hybrid optimization algorithm of particle swarm optimizer (PSO) and differential evolution (DE), was proposed. Optimum values of elasto-plastic mechanic parameters of rock mass were identified using the back analysis procedure and the measured displacement data. Assigning to the numerical model the optimum values of parameters, numerical simulation of powerhouse construction process was carried out to investigate the reliability of result of back analysis and the stability of powerhouse cavern. The result shows that calculated displacements are in good agreement with the measured, the powerhouse cavern is stable and has a considerable safety margin, and the existing support system can satisfy the need of local stability of powerhouse.

Back Analysis of Parameters and Settlement Prediction of Chengdu Clay Ground Considering Its Creep Behavior

2013 ◽  
Vol 671-674 ◽  
pp. 23-26 ◽  
Author(s):  
Yan Feng ◽  
Jian Fang Li
Keyword(s):  
High Speed ◽  
Back Analysis ◽  
Elastic Parameters ◽  
High Speed Railway ◽  
Settlement Prediction ◽  
Burgers Model ◽  
Railway Construction ◽  
Clay Ground ◽  
Railway Construction Project

Chengdu - Mianyang – Leshan (C-M-L for short) high speed railway in Chengdu section is located in the ground of weathered Mud rock overlying deep Chengdu clay area. Based on Chengdu clay ground of in high-speed railway construction project of CML, this article introduced the Burgers model to establish the objective function to analysis rheological constitutive model. The visco-elastic parameters of Burgers model are determined by back analysis of field monitoring data. By the method of iterative back analysis by layer of visco-elastic parameters, based on measured result, predicted the late settlement, and comparison with the follow-up observations records to verify the Burgers model.

An investigation of anisotropic elastic parameters of Bangkok Clay from vertical and horizontal cut specimens

2013 ◽  
Vol 8 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Wanwarang Ratananikom ◽  
Suched Likitlersuang ◽  
Siam Yimsiri
Keyword(s):  
Elastic Parameters ◽  
Anisotropic Elastic
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