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Cao Y.-B.,CAS Wuhan Institute of Rock and Soil Mechanics | Cao Y.-B.,Wuhan University | Feng X.-T.,CAS Wuhan Institute of Rock and Soil Mechanics | Yan E.-C.,Wuhan University | And 4 more authors.
Rock Mechanics and Rock Engineering | Year: 2015

Knowledge of the fracture hydraulic aperture and its relation to the mechanical aperture and normal stress is urgently needed in engineering construction and analytical research at the engineering field scale. A new method based on the in situ borehole camera measurement and borehole water-pressure test is proposed for the calculation of the fracture hydraulic aperture. This method comprises six steps. The first step is to obtain the equivalent hydraulic conductivity of the test section from borehole water-pressure tests. The second step is a tentative calculation to obtain the qualitative relation between the reduction coefficient and the mechanical aperture obtained from borehole camera measurements. The third step is to choose the preliminary reduction coefficient for obtaining the initial hydraulic aperture. The remaining three steps are to optimize, using the genetic algorithm, the hydraulic apertures of fractures with high uncertainty. The method is then applied to a fractured granite engineering area whose purpose is the construction of an underground water-sealed storage cavern for liquefied petroleum gas. The probability distribution characteristics of the hydraulic aperture, the relationship between the hydraulic aperture and the mechanical aperture, the hydraulic aperture and the normal stress, and the differences between altered fractures and fresh fractures are all analyzed. Based on the effects of the engineering applications, the method is proved to be feasible and reliable. More importantly, the results of the hydraulic aperture obtained in this paper are different from those results elicited from laboratory tests, and the reasons are discussed in the paper. © 2015 Springer-Verlag Wien


Yu K.,Shijiazhuang University of Economics | Zheng J.,Shijiazhuang University of Economics | Zhao M.,Qingdao Institute of Surveying and Mapping Survey | Li J.,Beijing New Oriental Star Petrochemical Engineering Co.
Geological Engineering and Mining Exploration in Central Asia - Proceeding Source: The XVIII Kerulien International Conference on Geology, KICG 2013 | Year: 2013

The dynamic compaction method, a kind of common foundation treatment method, is widely used in various soil foundation treatment due to its convenient, economical and feasible of construction. Because of the heterogeneity, the dynamic compaction design of filling soil foundation has long been a difficult problem in engineering field. In this paper, we studied the construction, detection, and improved treatment of dynamic compaction in a filling soil foundation site. The results show that the dynamic compaction method is not suitable for clay, silty soil; Because of the heterogeneity of the filling soil foundation, it is not reasonable to use the same parameters of construction in a whole site, and the construction parameters of filling soil foundation should be adjusted according to the different filling soils; The impact of dynamic compaction construction on groundwater level is obvious in filling soil foundation. The study will provide important basis and experience for strengthening mechanism research and design of dynamic compaction construction.


Song K.,Wuhan University | Yan E.-C.,Wuhan University | Yang J.,Wuhan University | Ji H.-B.,Wuhan University | Ji H.-B.,Beijing New Oriental Star Petrochemical Engineering Co.
Yantu Lixue/Rock and Soil Mechanics | Year: 2011

Storing oil in large underground caverns by water sealed is an important way of strategic oil reserve in the world. It needs to optimize the layout of caverns for the stability of such a large-scale unlined underground cavern. Based on the analysis of the engineering geological characteristic of an underground project in Shandong province, the numerical model was established. And the mechanical parameters of rock mass were estimated by the generalized Heok-Brown failure criterion with the integration of rock sample triaxial test and rock mass classification of rock mass rating (RMR) system. Choosing the depth, axial direction and space as factors, and calculated the displacement of the caverns by the FLAC3D code in different schemes, determined by the orthogonal design. The visual analysis of the results of the evaluating index, key point displacement and plastic zone area was done. The axial direction is the significant factor, and the influence on the stability was studied separately. The optimized layout of the underground caverns is that the depth is -60.0 m, axial direction is N30°W and space is 25 m. It has some values for the layout of the underground oil storage caverns.


Li D.,State Key Laboratory for GeoMechanics and Deep Underground Engineering | Li D.,China University of Mining and Technology | Zhao F.,State Key Laboratory for GeoMechanics and Deep Underground Engineering | Zhao F.,China University of Mining and Technology | And 3 more authors.
Applied Mechanics and Materials | Year: 2013

High speed camera system is used to record crack propagation on rock surface during the lab rocburst experiment. This paper presents the specific analytical method of crack propagation with high speed images. Crack propagation types and directions are briefly described, and the lengths, growth rate and fractal dimension of cracks are calculated. The results show that the crack grows mainly along the horizontal line on the unloading surface, at a low speed before rockburst and reaches a very high speed abruptly near the burst point. The fractal dimensions demonstrated that the crack turns to be rough when rockburst happens. The study on the crack propagation is benefit to the understanding on the mechanism of rockburst. © (2013) Trans Tech Publications, Switzerland.


Cao Y.,Wuhan University | Yan E.,Wuhan University | Hu D.,Beijing New Oriental Star Petrochemical Engineering Co. | Ji H.,Beijing New Oriental Star Petrochemical Engineering Co.
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | Year: 2014

For the issue that borehole camera technology only is applied to the vertical borehole currently, the calculation process for discontinuity orientation in inclined borehole is presented in this paper. With the circle centre of drill orifice as the origin, the left-handed Cartesian coordinate system is constructed and the precise analytic formulas for discontinuity orientation in inclined borehole are obtained. On this basis, the IDOIB software is developed using C# programming language. The validity of analytic formulas and program are verified by the principle of borehole camera technology. In addition, the PVC pipe experiments are conducted to examine the reliability of borehole camera technology for measurement of discontinuity orientation. Results show that: (1) For vertical holes, absolute errors of dip directions range from -3° to 4°, and those of dips range from -1. 5° to 1.0°. The technology is reliable for measurement of discontinuity orientation in vertical boreholes, and it can satisfy the needs of rock engineering. (2) For inclined PVC pipes with trend of 270° and plunge of 25°, the reliability degree of discontinuity orientation is 0.10; while inclined PVC pipes with trend of 176° and plunge of 60°, the reliability degree of discontinuity orientation is 0.67. The difference of pipe plunge results in the reliability difference of discontinuity orientation. (3) The reliability of discontinuity orientation should be high (the reliability degree is no less than 0.8) for general rock engineering, so the plunge of inclined borehole should be no less than 71°.


Song K.,China Three Gorges University | Song K.,Hubei University of Education | Yan E.,Hubei University of Education | Gao L.,Hubei University of Education | Liang J.,Beijing New Oriental Star Petrochemical Engineering Co.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2014

Underground oil storage caverns are the main mode to strategic crude oil storage in the world, which is the underground rock caverns below ground water level and prevented leakage by water sealed. And the permeability of surrounding rock mass would affect the stability of caverns, especially the anisotropic. Taking an oil storage caverns as a case, which is the first large oil storage project in China. Based on calculation of permeability tensor of Granitic Gneiss, the groundwater pressure distribution, flow velocity, displacement and stress in the surrounded rock was gained with different anisotropic permeabilities by finite element method(FEM). And the factor of safety of rock caverns was obtained by strength reduction on the Generalized Hoek-Brown criterion. It shows that anisotropic permeability of Granitic Gneisses has a significant effect on the groundwater pressure and flow velocity in surrounding rock, which the pressure increase linearly and flow velocity decrease logarithmic with increase of permeability anisotropy ratio. It has no effect on displacement and negligible on stress of surrounding rock. But it has a greater impact on factor of safety of rock caverns, which is general decreased with anisotropy ratio increased. It has some theoretical and engineering values to stability evaluation of underground water sealed oil storage caverns. ©, 2014, Academia Sinica. All right reserved.


Yu K.,Shijiazhuang University of Economics | Fan C.,Hebei Survey Institute of Environmental Geology | Li J.,Beijing New Oriental Star Petrochemical Engineering Co. | Liu Y.,Hebei Survey Institute of Environmental Geology
Geological Engineering and Mining Exploration in Central Asia - Proceeding Source: The XVIII Kerulien International Conference on Geology, KICG 2013 | Year: 2013

Debris flow is one of the familiar natural disaster in mountain areas, and is a kind of speacial flood current with great destructive power. The formation characteristics and classification of debris flow are the foundation of mechanism analysis, predication and forecast, disaster prevention and reduction. In this research, a typical mountain area of the north of China is selected as the study area. Meanwhile, based on analyzing the formation characterisitics of debris flow hazards, the comprehensive classification of debris flow is carried out according to the the five aspects, such as water source, landform features, material composition, damage degree, and human activity. In the study area, the formation of debris flow is mainly controlled by the factors of geology and rainfall, and the rainstorm-inducing feature is very obvious. Most of the debris flow in the study area should belong to rainstorm-gully-water-rock flow type.

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