Liu S.,Beijing Forestry University |
Wang H.,Beijing Forestry University |
Wang H.,China Institute of Water Resources and Hydropower Research |
Yan D.,China Institute of Water Resources and Hydropower Research |
And 3 more authors.
Advances in Meteorology | Year: 2017
Because of the impacts of extreme climate, the severity, areal extent, and frequency of rainstorm events are rapidly increasing, especially in the Huai River Basin of China. This article is based on hourly precipitation data of 229 meteorological stations from 1951 through 2012, combined with statistical and meteorological theory. We used the Mann-Kendall mutation test, moving t-test, and inverse distance weighting spatial interpolation to analyze the spatiotemporal evolution of precipitation, duration, intensity, and frequency of isolated rainstorm events under climate change. The main results are as follows: (1) isolated rainstorm events were obviously bimodal and their occurrence moved backward in time. Their average duration and time of maximum intensities changed dramatically, without a significant increasing trend. The period since the 2000s has seen an increase of rainstorms and their temporal regression across the entire basin. (2) The intensity of isolated rainstorm events in the study area decreased, but precipitation, its duration, areal extent, and frequency had increasing trends basin-wide. (3) Four rainstorm event indices were examined for the period of 1990-2000. Relative to the years before 2003, the average precipitation increased by 2.1%, the average total duration by 8.1%, and the average frequency of occurrence by 25.5%. All indices show smaller minimum and larger maximum values. Overall, the isolated rainstorm events tended to increase. © 2017 Simin Liu et al.
Lai X.,Xi'an University of Science and Technology |
Zheng J.,Xi'an University of Science and Technology |
Zheng J.,Beijing Huayu Engineering Co Ltd |
Jiang X.,Shenhua Xinjiang Energy Co Ltd |
And 3 more authors.
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2016
Surrounding rock of roadway here is deformed easily in fault regions. With coal excavation, concentrated stress formed before working face will cause movement or activation of faults, so that it can lead to a dynamic disaster. In response to the determination of the influential range of dynamic pressure in coal-rock fractured fault zone, taking the specific condition of No.1193 working face in Tunbao mine as the field research object. Combined with hybrid analyses, including mechanism analysis and field measurement, the stress distribution parameter inside the surrounding rock is collected through laying the stress detector and anchor bolt in the rib. It can be concluded that the scope of dynamic pressure within the stope is about 34 m, with the peak dynamic pressure occurring at 5 m before the working face. The assessment of the dynamic pressure can optimize the design of supporting reasonably and ensure the safety of the No.1193 working face in Tunbao colliery. © 2016, China University of Mining and Technology. All right reserved.
Liao B.,State Key Laboratory for Geomechanics and Deep Underground Engineering |
Zhou G.-Q.,State Key Laboratory for Geomechanics and Deep Underground Engineering |
Shang X.-Y.,State Key Laboratory for Geomechanics and Deep Underground Engineering |
Qiao L.-J.,Beijing Huayu Engineering Co.
Meitan Xuebao/Journal of the China Coal Society | Year: 2012
The new sensing technology based on sensitive conductive rubber's composites was studied for the deformation testing of geosynthetics. The rubber-composites filled with conductive filler were conductive, force sensitive, flexibility, and high elastic. Based on the composites, the new sensor was developed for the deformation testing of geotextile reinforcements which is flexible and the deformation is large. The new test technology was applied to the field measurement of reinforced soil retaining wall in a coal mine slot positions foundation. The results show that the tension of belt is proportional to the depth of soil, the maximum stress points appear in the 1/2 to 2/3 of length along the reinforced belt and the belt is safe. The new sensor provides a new method and mean for the deformation testing of reinforcement material.
Sha J.,China University of Mining and Technology |
Xie G.,China University of Mining and Technology |
Wang H.,Beijing Huayu Engineering Co. |
Liu J.,Beijing Huayu Engineering Co. |
Tang L.,CAS Institute of Process Engineering
International Journal of Mining Science and Technology | Year: 2012
A liquid-solid fluidized bed separator, used for the separation of coarse slime, was developed. Test particles sized in the range from 0.25 to 0.5, 0.5 to 1.0, and 0.25 to 1.0 mm were separated in the liquid-solid fluidized bed. Beds with column heights of 1200, 1500, and 1800 mm were tried. The clean coal and the tailings were subsequently analyzed by float-sink testing. The results showed that the ash and yield of clean coal both decreased with increasing column height, for all three size fractions, and that the ash of the clean coal obtained from tests on the broader size fraction was less than that from the narrower sized fractions. The separation density decreased with increasing column height. The lowest E value was seen for a column height of 1500 mm, for which conditions the separation density was 1.45 g/cm 3. The E value was 0.084 for the 0.25-0.5 mm fraction but the corresponding separation density was 1.48 g/cm 3, and the E value 0.089, for the broader 0.25-1.0 mm fraction. © 2012 Published by Elsevier B.V. on behalf of China University of Mining and Technology.
Ran J.-C.,China University of Mining and Technology |
Li G.-S.,China University of Mining and Technology |
Cao Y.-J.,China University of Mining and Technology |
Liu C.,Beijing Huayu Engineering Co.
Meitan Xuebao/Journal of the China Coal Society | Year: 2015
Specific nature property of mineral composition in coal fly ash is the key factor to depress froth stability of unburned carbon flotation. This study intends to improve froth stability via the addition of inorganic salt cations. Three different inorganic salt cations (Na+, Mg2+, Fe3+) were added into both solutions with only frother and flotation pulp system with ash particles. The influence of inorganic salt cations on foam and froth stability was studied systematically. The results indicate that the addition of salt cations improves the stability of gas-liquid foam and gas-liquid-solid froth. The stabilization function of Fe3+ to the foam or froth is stronger than Mg2+ and Na+. Based on the above study, the flotation of coal fly ash from Hubei province of China was conducted. Compared with flotation system with no salt cations, the LOI of low carbon product could be reduced from 8.85% to 5.57% in the flotation system with 3 mmol/L Fe3+. The unburned carbon removal rate of low carbon product is improved from 41.94% to 74.55%. Compared with flotation system with Fe3+, the function of Mg2+ and Na+ to the floatation indexes is weakened in due order. ©, 2015, Meitan Xuebao/Journal of the China Coal Society. All right reserved.
Song Q.-J.,CAS Wuhan Institute of Rock and Soil Mechanics |
Li H.-B.,CAS Wuhan Institute of Rock and Soil Mechanics |
Li J.-R.,CAS Wuhan Institute of Rock and Soil Mechanics |
Qu H.-Y.,Beijing Huayu Engineering Co. |
And 2 more authors.
Yantu Lixue/Rock and Soil Mechanics | Year: 2013
Equivalent nonlinear model is usually applied in seismic response analysis. The shear modulus and damping ratio are two important properties in this model. Highly weathered granite is common in large engineering. It is essential to study dynamic properties of highly weathered granite. The shear modulus and damping ratio of highly weathered granite are studied with GDS resonant-column; as its the capability is excellent, it is popular in the world. The confining pressure and pore water pressure to consolidate can be controlled well by GDS RCA. After the end of sample' consolidation, shear modulus and damping ratio can be given by experiment in the state of this effective stress. Changing confining pressure and pore water pressure, resonant frequency, shear modulus and damping ratio can be given with another effective stress. In different effective stresses, variation of shear modulus and damping ratio can be observed. And fitting curves of shear modulus and damping ratio that are put forward by Hadin-Drnevich are turned out on the basis of experimental data. The authors discuss the damping mechanism of highly weathered granite sample by amfusing frictional theory. It can be seen that resonance frequency of the sample's system has a positive correlation with shear strain, but sample's damping ratio has a negative with shear strain. The effective stress can have impact on both sample's shear modulus and damping ratio. However, pore water pressure can only act on damping ratio.
Zhou T.,Chang'an University |
Wu H.,Chang'an University |
Jiang L.,Baosteel |
Dong H.,Beijing Huayu Engineering Co.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2012
An experimental study on eight full scale specimens, composed of reclaimed sandwich board, calcium silicate board is carried out under monotonic horizontal loading and cyclic horizontal loading to investigate the feasibility of sandwich board replacing the traditional wallboard in cold-formed steel composite wall. The main failure modes and failure processes of these specimens are analyzed for the performance indices including yield load, maximum load, failure load, shearing stiffness and the structural ductility factor. Experimental results show that replacing the traditional wallboard with the structure of sandwich board with supporting steel X-strap bracing is feasible, steel X-strap bracing is capable of reducing the slippage at the interface of wallboards and significantly increasing the shear capacity of the composite walls. Compared with sandwich board cold-formed steel composite wall without external calcium silicate board, the shearing stiffness and shear capacity of the wall with external calcium silicate board increase indistinctively. The shear capacity of composite wall with double boards approaches to the sum of the shear capacity of composite wall with single sandwich board and that of the wall with single calcium silicate board.
Qiao L.-J.,China University of Mining and Technology |
Qiao L.-J.,Beijing Huayu Engineering Co. |
Zhou G.-Q.,China University of Mining and Technology |
Shang X.-Y.,China University of Mining and Technology |
And 2 more authors.
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2010
Loess is a special deposit which is very sensitive to water. Shear strength of loess-geobelt's interface changes with water content significantly. A series of direct shear tests for this interface with different water content are performed to obtain the relationship between water content and shear strength. The test results show that interface's shear strength of different water content meets Mohr-Coulomb criterion, and interface's friction angle and cohesion decreases nonlinearly with increasing water content. Then according to the test results, stability of the designed foundation ditch's reinforced earth wall in loess area is checked. The computing results indicate that the old design is unsafe because it has not taken the negative effect of increasing water contents into consideration. Finally, a new design is proposed which is able to satisfy the reinforced earth wall's inner stability with increasing water content properly.