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Che Y.,Beijing Research Institute of Uranium Geology | Zhao Y.,Beijing Research Institute of Uranium Geology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2017

Spectral stability characteristic parameter analysis is the basis of all the quantitative information extraction in hyperspectral image. The results show that the stability of the spectral parameters used in the spectral identification has a great influence on the efficiency of mineral identification. A mineral recognition method for hyperspectral remote sensing image based on spectral stability characteristic parameter is introduced. First,reference spectrum spectral peaks and valleyspositions were extracted, then calculates the measured spectra corresponding spectral wavelength and reference spectrum of each with a characteristic peak and valley of the correlation coefficient, basis of comparison of two spectral similarity to determine the matching effect of the two spectra, in order to achieve the best mineral identification precision and accuracy. Gansu BeishanShijinpo gold mining area as an example, the mineral identification map was obtained. After field verification, it was confirmed that the method has higher accuracyon the mineral recognition. © 2017 SPIE.

Cai M.,Laurentian University | Zhao X.,Beijing Research Institute of Uranium Geology | Kaiser P.K.,Center for Excellence in Mining Innovation
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2014

It is widely accepted that the field or in-situ strength of massive rocks is approximately (0.4±0.1) σc, where σc is the uniaxial compressive strength obtained from unconfined laboratory tests. In addition, it has been suggested that the in-situ rock spalling strength, i.e. the strength of the wall of an excavation when spalling initiates, can be set to the crack initiation stress determined from laboratory test or field microseismic monitoring. These findings were based on either Kirsch's solution or simplified numerical stress modeling(with smooth tunnel wall boundary) to approximate the maximum tangential stress σmax at the excavation boundary. In this article, it is suggested that these approaches ignore one of the most important factors, the irregularity of the excavation boundary. It is demonstrated that the "actual" in-situ spalling strength of massive rocks is not equal to (0.4±0.1) σc, but can be as high as (0.8±0.05) σc when surface irregularities are considered. It is demonstrated using the Mine-by tunnel notch breakout example that when the realistic "as-built" excavation boundary condition is honored, the "actual" in-situ rock mass strength, given by 0.8 σc, can be applied to simulate progressive brittle rock failure process satisfactorily. We conclude that the interpreted, reduced in-situ rock mass strength of (0.4±0.1) σc without considering geometry irregularity is therefore only an "apparent" rock mass strength.

Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: Fission-2009-1.1.1 | Award Amount: 6.53M | Year: 2010

The main aim of the project PEBS (Long-term Performance of the Engineered Barrier System) is to evaluate the sealing and barrier performance of the EBS with time, through development of a comprehensive approach involving experiments, model development and consideration of the potential impacts on long-term safety functions. The experiments and models cover the full range of conditions from initial emplacement of wastes (high heat generation and EBS resaturation) through to later stage establishment of near steady-state conditions, i.e. full resaturation and thermal equilibrium with the host rock. These aspects will be integrated in a manner that will lead to a more convincing connection between the initial transient state of the EBS and its long-term state that provides the required isolation of the wastes. The work proposed within the project builds on existing knowledge and experience generated during recent years and supported by ongoing nat. and EC research programmes. The project pretends to provide a more complete description of the THM and THM-C (thermo-hydromechanical-chemical) evolution of the EBS system, a more quantitative basis for relating the evolutionary behaviour to the safety functions of the system and a further clarification of the significance of residual uncertainties for long-term performance assessment. The importance of uncertainties arising from potential disagreement between the process models and the laboratory and in situ experiments to be performed within PEBS, and their implications for extrapolation of results will be reviewed, with particular emphasis on possible impacts on safety functions. In addition to the scientific-tech. aim, the consortium will spread the essential results to the european scientific community and Canada, Japan and China, use its expertise for public information purposes, and promote knowledge and technology transfer through training. WP 5 brings together activities concerning dissemination and training.

Yang G.-F.,Beijing Research Institute of Uranium Geology
Applied Mechanics and Materials | Year: 2014

On January 2, 2014, had the thermal infrared remote sensing image (TASI) near the drain of the Chang Jiang nuclear power station in Hainan Province plant. Due to the effect of external factors, such as the sun azimuth, the data within a single band appeared brightness gradient phenomenon. It was not conducive to the seawater temperature retrieval. Through research and analysis, established a model for thermal infrared image brightness gradient of the seawater. Based on quadratic polynomial fitting method, simulated the law of each kind of water after threshold classification, and then used the simulated compensation correction factors to correct the original image, had obtained a good application effect. © (2014) Trans Tech Publications, Switzerland.

Li Z.-W.,Beijing Research Institute of Uranium Geology
Wutan Huatan Jisuan Jishu | Year: 2015

Rayleigh wave exploration method is used in various fields of engineering survey widely, and a fast and accurate Rayleigh wave dispersion imaging method is one of the key factors in Rayleigh wave method. This paper introduce three dispersion imaging methods implementation in detail by synthetic data, and analysis the dispersion imaging results of different imaging methods, by comparison, we can clearly see the Rayleigh wave distribution of energy in the imaging results of F-K transform method and τ-p transform method, but it is not conducive to the dispersion curve extraction, and the phase shift method has better dispersion imaging results, and can get a higher frequency and higher order Rayleigh wave dispersion curves.

Qiu G.H.,Beijing Research Institute of Uranium Geology
Applied Mechanics and Materials | Year: 2014

The Radioactive waste management technology is briefly introduced in this article based on related standards, guidelines and documents from IAEA. The radioactive waste management technology(RWM) includes related international standards and conventions, predisposal radioactive waste management, RWM for radioactive waste disposal, RWM for remediation, NORM and mining/milling waste. These management methods and valuable experience have important reference value to waste classification, waste disposal and management and related work in China. © (2014) Trans Tech Publications, Switzerland.

Wang J.,Beijing Research Institute of Uranium Geology
Journal of Rock Mechanics and Geotechnical Engineering | Year: 2014

Underground research laboratories (URLs), including "generic URLs" and "site-specific URLs", are underground facilities in which characterisation, testing, technology development, and/or demonstration activities are carried out in support of the development of geological repositories for high-level radioactive waste (HLW) disposal. In addition to the generic URL and site-specific URL, a concept of "area-specific URL", or the third type of URL, is proposed in this paper. It is referred to as the facility that is built at a site within an area that is considered as a potential area for HLW repository or built at a place near the future repository site, and may be regarded as a precursor to the development of a repository at the site. It acts as a "generic URL", but also acts as a "site-specific URL" to some extent. Considering the current situation in China, the most suitable option is to build an "area-specific URL" in Beishan area, the first priority region for China's high-level waste repository. With this strategy, the goal to build China's URL by 2020 may be achieved, but the time left is limited. © 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences.

Zhu L.,Beijing Research Institute of Uranium Geology
IOP Conference Series: Earth and Environmental Science | Year: 2014

Commonly, it requires two constraints imposed on the linear spectral mixture analysis (LSMA). One constraint is the abundance of sum-to-one, which requires the abundance fractions of materials presented in an image pixel to be one and is easy to deal with. The other constraint is that any abundance fractions are always nonnegative and difficult to solve with analytical solution. Most of approaches that provide the solution for the latter problem of LSMA use an optimization or maximization procedure. The results of solution resort to optimization strategies. The Leontief input-output model, of which parameters are very similar to LSMA, is represented by a linear system of equations and the system has a unique nonnegative solution. In this paper, we considered how to determine the parameters of LSMA model, and based on the open Leontief input-output model, we presented a fully constrained linear spectral (FCLS) mixture analysis method for estimating material abundance in spectral mixture pixel. The new FCLS method can not only make the abundance fractions of materials be nonnegative, but also keep them less than one, that always obtained by normalizing procedure in other methods. We also examine a number of approaches, previous FCLS and non-negative matrix factorization (NMF) spectral un-mixing, closely related. A series of computer simulations are conducted to demonstrate the performance of the proposed method in material quantification.

Zhao X.G.,Beijing Research Institute of Uranium Geology | Zhao X.G.,Laurentian University | Cai M.,Laurentian University
International Journal of Rock Mechanics and Mining Sciences | Year: 2010

Excavation-induced rock failure and displacement near an underground opening boundary is closely associated with rock mass dilation. A better understanding of rock mass dilation around the excavation helps us to predict or anticipate displacements and extent and shape of the failed zone, and subsequently assist design of proper ground support systems. A calibrated cohesion weakening and frictional strengthening (CWFS) model with a constant dilation angle can capture the stress-induced brittle failure shape in hard rocks. However, the use of a constant dilation angle, in either CWFS, Mohr-Coulomb perfectly elasto-plastic, or Mohr-Coulomb strain-softening models, cannot simulate the displacement distribution near the excavation reasonably. In the present study, numerical simulations are performed to study excavation-induced displacement around tunnels located in different rock mass types, i.e., coarse-grained hard rock, medium-grained hard rock, fine-medium-grained soft rock, and fine-grained soft rock, using a mobilized dilation angle model that depends on both confining stress and plastic shear strain. It is illustrated from a few examples that displacement distributions obtained from the dilation angle model are more reasonable when compared with the general trend measured underground. © 2010 Elsevier Ltd.

Zhao X.G.,Beijing Research Institute of Uranium Geology | Zhao X.G.,Laurentian University | Cai M.,Laurentian University
International Journal of Rock Mechanics and Mining Sciences | Year: 2010

Experimental and field observations of rock failure show that the failure process is closely associated with rock dilation, an indicator of volumetric increase during rock deformation. The most common concept used to describe dilation is the dilation angle. The conventional Mohr-Coulomb model considering strain-softening often makes an assumption of constant dilation, but it is observed that the approach is not successful in characterizing the nonlinear deformation behavior of rocks. In the present study, based on published data acquired from modified triaxial compression tests with volumetric strain measurement, a mobilized dilation angle model considering the influence of both confining stress and plastic shear strain is established. Based on the model response and in combination with the grain size description and the uniaxial compressive strength, the model parameters for four rock types (coarse-grained hard rock, medium-grained hard rock, fine-medium-grained soft rock, and fine-grained soft rock) are suggested. For coal and quartzite representing fine-grained soft rock, and coarse-grained hard rock, respectively, the dilation angle model is used to predict the volumetric-axial strain relationships, and the predictions are found to be in good agreement with experimental results. © 2009 Elsevier Ltd. All rights reserved.

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