Parameter identification method for determination of elastic modulus of rock based on adjoint equation and blasting wave measurements

Koizumi, Naoto; Kawahara, Mutsuto

doi:10.1002/nag.779

Cited by 3 publications

(5 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These values are obtained by previous studies of the numerical computations performed by the authors' group (e.g. Koizumi and Kawahara [2009]). These are determined such that the order of the computed velocity almost corresponds to the order of the observed velocity.…”

Section: Ohyorogi Tunnelmentioning

confidence: 89%

“…Integrating J * (1) 1 , J * (2) 1 and J * (3) 1 by parts (see Koizumi and Kawahara [2009]), the adjoint equation for λ (0) αi and the terminal condition can be obtained.…”

Section: Adjoint Equationsmentioning

confidence: 99%

“…In a previous study (Koizumi and Kawahara 2009), the identification is presented assuming that the three components of the blast force are equal. In this article, the identification of the three components, A i , of the magnitude of the blast force is reported.…”

Section: Identification Of the Blast Forcementioning

confidence: 99%

“…The method for identifying the elastic modulus of a rock was reported previously by Koizumi and Kawahara (2009). In that study, the number of identifiable elastic moduli was limited to one; that is, the elastic modulus of only one stratum could be identified.…”

Section: Identification Of Elastic Modulusmentioning

confidence: 99%

“…Email: kawa@civil.chuo-u.ac.jp those articles. Parameter identification based on dynamic motion was carried out by Koizumi and Kawahara (2009), in which the first-order adjoint equation method was presented and the borehole pressure was assumed to propagate toward surrounding rocks with equal magnitude. After several numerical computations, the following conclusions were reached, which are part of the motivation for conducting the present study.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Second-order adjoint equation method for parameter identification of rock based on blast waves in tunnel excavation

Motoyama

Mikame

Nojima

et al. 2013

Engineering Optimization

Self Cite

View full text Add to dashboard Cite

The objective of this study is to present a method for identifying the elastic moduli of ground rock via the first-and second-order adjoint methods using blast vibration measurements during tunnel excavation. For identifying these parameters, the magnitudes of the blast force should be identified beforehand. Parameter identification is a minimization problem of the square sum of the discrepancy between the computed and observed velocities. The magnitudes of the three components of borehole pressure are assumed to be independent in each direction. The propagation of an elastic wave is assumed because the amplitude of such a wave is infinitesimal. The three-dimensional finite element method and the linear acceleration method are used effectively. The extended performance function can be expanded into a series of small constants to derive the necessary condition of minimization. The adjoint equation and the dynamic equation of motion can be used to obtain the gradient and the Hessian product of the extended performance function with respect to the parameters. The weighted gradient method and Broyden-Flecher-Goldfarb-Shanno method are successfully employed for the minimization. By applying the present identification technique at the Ohyorogi tunnel site, the fact that the computed and observed velocities are well in agreement is verified. The present method can be shown to be useful for tunnel excavation.

show abstract

Section: Ohyorogi Tunnelmentioning

confidence: 89%

“…Integrating J * (1) 1 , J * (2) 1 and J * (3) 1 by parts (see Koizumi and Kawahara [2009]), the adjoint equation for λ (0) αi and the terminal condition can be obtained.…”

Section: Adjoint Equationsmentioning

confidence: 99%

Section: Identification Of the Blast Forcementioning

confidence: 99%

Section: Identification Of Elastic Modulusmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Second-order adjoint equation method for parameter identification of rock based on blast waves in tunnel excavation

Motoyama

Mikame

Nojima

et al. 2013

Engineering Optimization

Self Cite

View full text Add to dashboard Cite

show abstract

Poisson's Ratios of Honeycomb‐Structured Polymer Sheets Under Large Deformation

Kim

Hwang

et al. 2011

Macro Chemistry & Physics

View full text Add to dashboard Cite

The mechanical properties of 2D honeycomb-structured polymer sheets (HSPS) are investigated with respect to the polar angle at large deformation. The tensile force fl uctuates as an undamped negative sinusoidal wave with a periodicity of 15 ° . The amplitude of the fl uctuation is proportional to the thickness of the HSPS, but the Young's modulus is independent of the thickness and the polar angle. Total and local Poisson's ratios of HSPS at the 30 ° polar angle are lower than those obtained at the 0 ° polar angle over the entire strain range, and the difference becomes smaller with increasing tensile strain. The experimentally observed structure-property relationship of the HSPS can provide important clues for understanding the deformation behavior of patterned polymeric materials.

show abstract

Identification of the Elastic Modulus of Ground Rock based on Blasting Waves using the Adjoint Method

Motoyama

Proceedings of the Seventh International Conference on Engineering Computational Technology

View full text Add to dashboard Cite

The purpose of this research is to identify the elastic modulus of ground rock using an optimal control theory, which is the first order adjoint method. Elastic modulus is one of parameter to express geological condition. In order to perform safety constructions and reduce costs, it is important to know elastic modulus in advance. To identify the elastic modulus, the velocity of elastic waves are observed. The velocity of elastic waves are caused by the blasts with dynamite. The Optimal elastic modulus is identified using the first adjoint method so as to minimize the performance function, which is defined by the square sum of residual discrepancies of between the calculated and observed velocities. To calculate the state quantity in the ground, following basic equations are used in this research. As the basic equation, the equilibrium of stress equation, the strain-displacement equation and the stress-strain equation are used. The first order adjoint equation is used to calculate the gradient of the performance function. The weighted gradient method is applied to minimization technique. To solve the basic and adjoint equation, the finite element method and the Newmark β method are applied for the spatial and temporal discretizations, respectively. As the external force, borehole pressure is employed. The elastic modulus can be identified using these methods. For application to actual phenomenon, Ohyorogi-tunnel excavation site is adopted. It is located in Hiroshima prefecture, Japan.

show abstract

Parameter identification method for determination of elastic modulus of rock based on adjoint equation and blasting wave measurements

Cited by 3 publications

References 9 publications

Second-order adjoint equation method for parameter identification of rock based on blast waves in tunnel excavation

Second-order adjoint equation method for parameter identification of rock based on blast waves in tunnel excavation

Poisson's Ratios of Honeycomb‐Structured Polymer Sheets Under Large Deformation

Identification of the Elastic Modulus of Ground Rock based on Blasting Waves using the Adjoint Method

Contact Info

Product

Resources

About