Identification of damage parameters for jointed rock

Xiang, Zuoshuang; Swoboda, G.; Cen, Zhangzhi

doi:10.1016/s0045-7949(02)00086-x

Cited by 15 publications

(5 citation statements)

References 23 publications

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“…The back analysis method for identifying the properties of the materials is essentially equivalent to the problem of identification of the material parameters P (in this case, damage tensor X) by observing the loadst on the part S u of the boundary S u , where the displacementsû are given, or by observing the displacementsū on the part S t of the boundary S t where the loadst are given [13][14][15]. The model is symbolically shown in Figure 1.…”

Section: Constitutive Equationmentioning

confidence: 99%

Identification of damage parameters for discontinuous rock mass

Ohkami

Maruden

Koyama

2009

Int. J. Numer. Meth. Biomed. Engng.

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SUMMARYThis paper presents an identification method for a discontinuous rock mass employing damage mechanics theory and wavelet analysis. Parameter identification methods based on deterministic approaches are classified into inverse and direct approaches. The proposed method combines the inverse approach and the direct approach and by applying the discrete wavelet transform to the system matrix of the iteration equation, we estimate unknown damage tensors for the case in which the number of unknown parameters exceeds the observed data. The validity of this method is examined for geotechnical engineering problems.

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Section: Constitutive Equationmentioning

confidence: 99%

Identification of damage parameters for discontinuous rock mass

Ohkami

Maruden

Koyama

2009

Int. J. Numer. Meth. Biomed. Engng.

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“…Kan and Li and Zhang [19,20] analyzed the settlement pattern of buildings produced by tunnel construction using the finite difference method (FDM). Godinho et al [21][22][23] applied finite element calculation procedures combined with neural networks and other methods to investigate the environmental changes caused by tunnel excavation. In addition, they analyzed the changes and proposed corresponding prediction tools.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Settlement Induced by Shield Construction of the Metro Passing under Existing Buildings Based on the Finite Difference Method

2022

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A frequent problem when constructing metro tunnels is the uneven settlement of adjacent buildings, which results in huge economic losses. Due to shields causing the settlement of adjacent buildings, this study took the Nantong Metro Line 1 as the research object. The metro runs from the East Huancheng Road Station to the Nantong Intermediate People’s Court Station and passes under the old residential area of the Community Sendadi-Huayuan building. Based on the settlement monitoring data, this study analyzed the impact of tunnel shield construction on the foundation settlement of adjacent buildings. The computational analysis of the shield tunnel was performed by numerical simulation, taking into account the upper building load and the construction disturbance to the surrounding rock. Afterward, the study summarized the law behind the settlement. The results show that when the boring machine was tunneling through sandy soil and silt rich in water, its head was prone to twisting due to soil disturbance and the dissipation of pore water, causing instability in the excavation process and eventual ground settlement. In the sandy strata, the relationship between foundation settlement caused by shield construction and time can be approximated as an exponential function in a certain area. The vibrations from shield excavation caused the foundations to vibrate for a short period of time. Therefore, the average settlement of buildings directly above the underpass reached 7 mm/d. Likewise, the tunneling shield caused a 1.5 mm settlement before passing under the building. It caused a peak settlement of 4.0 and 5.1 mm during and after passing under the buildings, respectively. The width of the settlement troughs of approximately 7D formed after the tunnel was excavated. Shield excavation placed the soil at the top of the excavation face in a state of tensile stress, causing tensile and shear damage to the soil and forming a local plastic zone.

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“…Therefore, a robust inverse identification technique that can reliably estimate parameter values based on available experimental observations is crucially important in order to achieve satisfactory predictability of the damage constitutive model. Most of the existing inverse parameter estimation methods apply optimization techniques in order to minimize cost functions that represent differences between numerical simulation results and experimental test data in terms of displacements (Ghaboussi et al, 1998;Lauro et al, 2001;Xiang et al, 2002), loads (Brunet et al, 2004;Kuna and Abendroth, 2004), both displacements and forces (Abendroth and Kuna, 2006;Munoz-Rojas et al, 2010), or modal characteristics such as natural frequencies and/or mode shapes, etc. (Friswell, 2007;Singh, 2009).…”

Section: Introductionmentioning

confidence: 99%

Parameter estimation of a rate-dependent damage constitutive model for damage-tolerant brittle composites by Self-OPTIM analyses

Shang

Yun

Kim

et al. 2012

International Journal of Damage Mechanics

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This article demonstrates a novel parameter identification of a rate-dependent damage constitutive model using self-optimizing inverse method. In the self-optimizing inverse method, an implicit-explicit objective function is formulated as a function of two sets of full-field stresses/strains (implicit non-measurable variables) from two nonlinear finite element analyses, that is, force-driven and displacement-driven simulations, respectively, and global boundary displacements and forces (explicit measurable variables) from experimental tests. The self-optimizing inverse method can self-correct the damage parameter set through optimization procedures referring to global responses measured in laboratory tests. A micromechanics and fracture mechanics based damage constitutive law that accounts for the microcrack nucleation and growth is adopted. Synthetic data from impact tension test simulations were used to demonstrate successful performances of the self-optimizing inverse method in identifying the nonlinear constitutive and damage-related parameters. Comparative studies were conducted using two different optimization techniques -the simplex method and the steady-state genetic algorithm. The identified parameters proved to be identical to the reference values. Finally, in order to further verify the inverse identification method, self-optimizing inverse method analyses were conducted to identify the damage parameter set based on real experimental data from impact tension tests at different strain rates.

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Identification of damage parameters for jointed rock

Cited by 15 publications

References 23 publications

Identification of damage parameters for discontinuous rock mass

Identification of damage parameters for discontinuous rock mass

Analysis of Settlement Induced by Shield Construction of the Metro Passing under Existing Buildings Based on the Finite Difference Method

Parameter estimation of a rate-dependent damage constitutive model for damage-tolerant brittle composites by Self-OPTIM analyses

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