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Wang S.,CAS Wuhan Institute of Rock and Soil Mechanics | Li X.,CAS Wuhan Institute of Rock and Soil Mechanics | Wang S.,Northern Engineering and Technology Corporation | Shi L.,CAS Wuhan Institute of Rock and Soil Mechanics | And 2 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2015

Based on neural network method, the influence of gravel-soil gradation on permeability coefficient was studied. Obtaining 92 groups seepage test data of gravel-soil, a neural network was trained and tested. Based on this neural network, permeability coefficient of gravel-soil was predicted and compared by full gradation (d10-dmax, all particle size) and a few gradation character respectively. Then mean impact value method was used to analyze the influence of each particle size on the permeability coefficient, and the degree of influence was given. At last, the reliability of the above analysis was verified by a set of laboratory test. The following conclusions were obtained: the permeability coefficient of gravel-soil predicted by full grade can be more accurate, while with great uncertainty by one or a few gradation character. There are limitations in the application of current empirical formulas. d10 is the key grain, which is different from coarse particle soli generally with d20 the key particle size. Coefficient permeability of gravel-soil decreases with the increase of dmax, coarse particles play an important role in the control of permeability coefficient. d50 is the boundary particle size, increasing the particle size below or above d50, the permeability coefficient will increase or decrease correspondingly. ©, 2015, Academia Sinica. All right reserved.


Wang H.,CAS Wuhan Institute of Rock and Soil Mechanics | Li X.,CAS Wuhan Institute of Rock and Soil Mechanics | Mi Z.,Mining Company | Bai J.,Mining Company | Wang S.,Northern Engineering and Technology Corporation
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2011

Based on the investigation, test and numerical analysis of the mine dumps, it is believed that the key of disaccord between results from the 2D-LEM and reality is system spatial effect under the interaction of base and dump body. The spatial clamp effect of convex and divergent effect of concave are explained, as well as essential relationship between height and radius of curvature which should be abided by 2D or 3D stability analysis is given on the basis of field test, theoretical analysis and physical model. Furthermore, the safe class, evaluation criterion and technical route which takes the factor of stability as major and also considers stress, displacement fields and plastic region distribution is established, under the principle that the deformation and partial failure are allowable.


Li X.,CAS Wuhan Institute of Rock and Soil Mechanics | Ren W.,CAS Wuhan Institute of Rock and Soil Mechanics | Wang S.,Northern Engineering and Technology Corporation | Wang H.,CAS Wuhan Institute of Rock and Soil Mechanics | Cui Y.,CAS Wuhan Institute of Rock and Soil Mechanics
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2011

There are some controversies on the selection of stability calculation methods when preparing for the new specification of waste dump. We evaluate the accuracy and applicability of 7 limit equilibrium methods by using the difference percentage and standard deviation of safety factors in waste dump slope stability analysis. Combined with previous research, the application of limit equilibrium method in waste dump slope analysis is described. Ordinary method has a poor accuracy. The accuracy is larger than 30% and the standard deviation is large when dealing with ground water problem. Its calculation result can be used as a lower limit. Bishop method has an accuracy of 3.7% and good standard deviation, although only satisfying moment equilibrium. For the simple algorithm, it is recommended as a basic method. The correct values can be obtained from methods satisfying force and moment equilibrium, which applies to a variety of conditions.


Wei S.,Dalian University of Technology | Lv Y.,Dalian University of Technology | Fu B.,Northern Engineering and Technology Corporation | Yoshino H.,Tohoku University
Procedia Engineering | Year: 2016

In recent years, prevalence rate of children's allergic diseases gradually increases, children's health problems are not optimistic. Epidemiological cross-sectional survey method was used in this study. 120 school-age children of Grade Four and Five were selected to do the questionnaire on living environment and health problem in Dalian. Then 10 residents were selected to detect indoor environmental information. This study explored the correlation of living environment and children's allergic diseases by some hypothesis testing methods and analyzed exposure levels of various pollutants. Living in the surrounding road, re-decoration, updating ventilation equipment, moist sensation, milk feeding in lactation, usually light sleep were risk factors of certain allergic diseases. SVOC, planktonic fungi, accumulated fungi had a positive effect on disease group, while adherent fungi had a negative effect. The average level of exposure of diseases group is higher than control groups. © 2016 Published by Elsevier Ltd.


Xie G.,China University of Mining and Technology | Wu L.,China University of Mining and Technology | Li G.,Northern Engineering and Technology Corporation | Yu H.,University of Calgary
Mining Science and Technology | Year: 2010

The use of wash oil as a coal collector is proposed to overcome the disadvantages of regular collectors in coal slime flotation. These disadvantages include high price, limited sources and high consumption. The effect of additives on flotation was studied and an innovative "one rough separation - one cleaning separation" flotation technology was developed. The experimental results show that the clean coal ash content decreases by about 1.36 and the clean coal yield declines by around 10 with the application of the depressant. There is an increase of 3.76 in the yield of clean coal and a decrease of 0.40 in the ash content caused by utilizing a dispersant. An ultimate product having an ash content of 10.78 and yield of 70.12 can be attained using a combination of dispersant and depressant. The use of this new technology decreases the ash content by 1.21, decreases the yield by 2.80 and an increases the coal flotation perfect index by 2.03. Compared to common flotation, the utilization of the new technology reduces ash by 0.17, increases yield by 5.3 and increases perfect index by 4.18. © 2010 China University of Mining and Technology.


Liu J.,Northeastern University China | Liu Z.,Northern Engineering and Technology Corporation | Wang S.,Northern Engineering and Technology Corporation | Shi C.,Northeastern University China | And 2 more authors.
International Journal of Mining Science and Technology | Year: 2016

Aiming at evaluating the stability of a rock mass near a fault, a microseismic (MS) monitoring system was established in Hongtoushan copper mine. The distribution of displacement and log(EI), the relationship between MS activity and the exploitation process, and the stability of the rock mass controlled by a fault were studied. The results obtained from microseismic data showed that MS events were mainly concentrated at the footwall of the fault. When the distance to the fault exceeded 20 m, the rock mass reached a relatively stable state. MS activity is closely related to the mining process. Under the strong disturbance from blasting, the initiation and propagation of cracks is much faster. MS activity belongs in the category of aftershocks after large scale excavation. The displacement and log(EI) obtained from MS events can reflect the difference in physical and mechanical behavior of different areas within the rock mass, which is useful in judging the integrity and degradation of the rock mass. © 2016 Published by Elsevier B.V. on behalf of China University of Mining & Technology.


Liu J.-P.,Northeastern University China | Li Y.-H.,Northeastern University China | Xu S.-D.,Northeastern University China | Xu S.,Northeastern University China | And 2 more authors.
Engineering Fracture Mechanics | Year: 2015

Acoustic Emission (AE) technique and moment tensor (MT) analysis were both applied to study the spatial-temporal evolution of micro-cracks of coarse-grained granite samples, containing a circular opening, which were subjected to uniaxial compression. The results show that AE locations are in agreement with the macroscopic fractures, observed on the surface of the granite specimens after the end of the experiments. Shear cracks are dominant as the ratio is more than 40% of the total number of events, tension cracks are fewer, since they accounted for more than 30% of the total events, and mixed-mode cracks represent a minimum proportion. © 2015 Elsevier Ltd.


Kang Y.-M.,Northeastern University China | Zhao S.-Y.,Northern Engineering and Technology Corporation | Wang T.-T.,Northeastern University China | Liu S.-Z.,Northeastern University China
Dongbei Daxue Xuebao/Journal of Northeastern University | Year: 2015

Based on the characteristics of acoustic emission(AE) signals of rock, decomposition, de-noising and reconstruction for the acoustic emission signals were conducted through wavelet packet transform. It is found that the signal denoised by the wavelet packet transform (WPT) method has a higher signal-to-noise ratio (SNR) and a lower distortion than those by other methods based on wavelet transform (WT) methods and the WPT method shows the overall superiority. ©, 2015, Northeastern University. All right reserved.


Li Y.-G.,Northeastern University China | Kong X.-N.,Northern Engineering and Technology Corporation | Gao Y.-Y.,Northeastern University China
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2015

Considering that the bolt looseness induces the variation of dynamic parameters of joint of bolt connection, a detection method was proposed based on vibration signals of two connected parts. The probability densities of the two signals were calcuated, the probability density curves were processed by a mesh to obtain probability matrixes, and were the probability matrixes were transformed by using principal component analysis (PCA) method. After PCA, two projection matrixes of the probability matrixes were merged to one matrix. To this matrix, PCA and projection were implemented again. According to the peculiarity of bolt looseness, tow detection modes are designed based on the proposed method. The mode 1 carries out training work using foregone samples to generate projection points of each looseness condition employing the proposed method, then in detection, Euclidean distance between projection point and each foregone projection point was used as estimation criterion. The mode 2 directly detects looseness condition by using proposed method based on the signals of tight bolt connection condition and field measurement, and a criterion for judging bolt looseness was designed. The experimental verification shows that the proposed method can distinguish different looseness conditions, and the detection mode 2 is easy and simple to be handled without foregone fault samples. ©, 2015, Chinese Vibration Engineering Society. All right reserved.


Dong H.,Northeastern University China | Li J.,Northeastern University China | Luo Y.-Q.,Northern Engineering and Technology Corporation | Cai J.-J.,Northeastern University China
Dongbei Daxue Xuebao/Journal of Northeastern University | Year: 2010

An experimental setup was provided to investigate the cooling process of sinter and relevant influencing factors on the process. The results showed that the cooling air flowrate and thickness of sinter bed are both the main factors. With the thickness of sinter bed kept unchanged and increasing cooling air flowrate, the temperature of hot air passing through the sinter bed decreases gradually, while the sensible heat of hot air begins to increase and comes up to its peak value, then decreases gradually. It implies that there is an appropriate value at which the hot air carries maximum. Moreover, keeping up the opening of air-blower constant, the hot air temperature increases gradually with the increasing thickness of sinter bed, and there is an appropriate value of the thickness, too. The appropriate thickness and appropriate cooling air flowrate affect and constrain mutually.

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