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Li J.,Central South University | Li J.,Hunan Normal University | Tang J.-T.,Central South University | Xu Z.-M.,Central South University | And 2 more authors.
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2017

It is a very challenging task to carry out the high-precision signal-to-noise separation for magnetotelluric sounding data in ore concentration area. In order to avoid “over processing” of morphological filtering method in the strong interference separation, and further reserve the useful information of magnetotelluric sounding data in low frequency band, a new method of magnetotelluric noise suppression base on signal-to-noise identification is proposed in this paper. First of all, according to the different complexity of morphological characteristics between the strong interference types of ore concentration area and natural magnetotelluric signal, we combine mathematical morphology, fractal dimension and morphological spectrum, introducing the robust characteristic parameters-morphological fractal dimension and morphological spectrum entropy to quantitatively indentify magnetotelluric signal and strong interferences. Then, we combine morphological filtering technology with threshold method to suppress noise, which is not natural magnetotelluric signal but abnormal waveform by identification. Finally, we reconstruct the useful signal of magnetotelluric and evaluate algorithm performance. Simulation results show that the proposed method can be more finely reserve the slow change information in low frequency band, and the reconstructed time series of magnetotelluric are approach to the essence characteristics of natural magnetotelluric signal. When it suppresses the adjacent source interference in ore concentration area, the method can effectively avoid the “over processing” of the morphology filtering technology in the noise suppression, and the integral morphology of Cagniard resistivity-phase curve is more smooth and continuous. Moreover, the apparent resistivity values are relatively stable. The results are more truly reflect the inherent deep structure information of measured data itself, and the overall data quality of the low frequency band has been improved significantly. © 2017, Science Press. All right reserved.


Hu J.,Longdong University | Hu J.,Provincial Key Laboratory of Yellow Soil Engineering Properties and Applications | Wang J.,Northwest Research Institute of Engineering Investigations and Design | Zhang J.,Longdong University | Cheng Z.,Gansu Agricultural University
Paiguan Jixie Gongcheng Xuebao/Journal of Drainage and Irrigation Machinery Engineering | Year: 2017

The influences of sand content on free infiltration characteristics of muddy water film hole irrigation and water content distribution in wetted soil are studied experimentally. Through indoor free infiltration of clean water film hole irrigation experiments with four different sand contents in muddy water, the relationships between free infiltrations of muddy water film hole infiltration parameters, wetting front transport parameters and wetted soil water content distribution parameters after the irrigation and the different sand contents are established. A cumulative infiltration model per unit film area, wetting front transport model, wetted soil water content distribution model and film infiltration declining feature due to the increasing sand content are put forward. It is demonstrated that with increasing muddy water sand content, the cumulative infiltration decreases and less than that of clean water under the same condition. The infiltration coefficient K decreases with increasing sand content, but the infiltration index α increases with the increasing content. In the same infiltration time, with increasing sand content, the vertical and horizontal wetting front transport distances are gradually reduced. With increasing distance from the center of film hole, the water mass content in wetted soil reduces gradually in the vertical and horizontal directions. The sand contents in muddy water can reduce film hole irrigation infiltration in comparison with clean water, particularly, the higher the sand content, the smaller the infiltration rate. © 2017, Editorial Department of Journal of Drainage and Irrigation Machinery Engineering. All right reserved.


Jianlong Y.,Northwest Research Institute of Engineering Investigations and Design | Jun W.,Northwest Research Institute of Engineering Investigations and Design | Shijie S.,Xi'an University of Science and Technology | Zhihai Z.,Northwest Research Institute of Engineering Investigations and Design
Advanced Materials Research | Year: 2012

As an important exporter of coal resources in China, Yulin has made great contribution to the repaid development of the national economy. But, the geological disaster item caused by large-scale exploitation of coal resources is becoming more and more serious. On the basis of county geological disaster investigation data in Yulin, the research analyzes and summarizes the type, scope, damage degree of the geological disaster in the whole city, especially coal area qualitatively and quantitatively. The article makes clear the spatial distribution of geological disasters in Yulin and it hope that the work can provide scientific guidance to geological disaster prevention in the future. By the research, we get several results as follow: First, there are 905 geological disasters points in Yulin and the mainly the types of all are Collapse, Landslide, Debris Flow, Unstable Slopes, and Ground Subsidence; Second, Collapse and Landslide are the major geological disasters type, and Ground Subsidence is the most serious hazard type in Yulin although its number is small. Third, according to the result above, the city has been divided into different geological disaster-prone areas with MAPGIS, and there are 11 high geological disaster-prone areas, 12 middle, 8 low and 3 undeveloped areas. © (2012) Trans Tech Publications, Switzerland.


Wu J.,Xi'an University of Technology | Zhu D.,Xi'an University of Technology | Liu Y.,Jiangxi Provincial Research Institute of Water Resources | Tao W.,Xi'an University of Technology | Wang J.,Northwest Research Institute of Engineering Investigations and Design
Paiguan Jixie Gongcheng Xuebao/Journal of Drainage and Irrigation Machinery Engineering | Year: 2016

In order to judge the comprehensive application of irrigation district scientifically and achieve the benefit maximization, comprehensive evaluation of operational status of large-scale irrigation district is necessary. First, the Delphi and the fuzzy analysis method are combined; then the structure of entropy method is introduced based on the information entropy to evaluate the evaluation indexes; finally, the close value method is used to evaluate Luohuiqu irrigation operational status of the 2007-2012 years. The results show that the close value of the irrigation district in 2007-2012 is 2.7192, 2.2051, 1.3117, 0.4855, 0.1888, and 0, respectively, and its operational condition is getting better and better. The close value of adjacent years is 0.5142, 0.8933, 0.8263, 0.2967, and 0.1888, tending to a stable condition. The comprehensive evaluation of operational status of large-scale irrigation district based on modified close value method roughly agrees with the evaluation results with the method of grey correlation theory-TOPSOS. The operational condition is getting better and better with the passage of time and more accurate, which also accords with the actual development of Luohuiqu irrigation district. This method is simple in calculation and has high reliability. © 2016, Editorial Department of Journal of Drainage and Irrigation Machinery Engineering. All right reserved.


Cui G.-Q.,Xi'an University of Architecture and Technology | Ma C.-G.,Northwest Research Institute of Engineering Investigations and Design | Xu Y.-L.,West Anhui University
Xi'an Jianzhu Keji Daxue Xuebao/Journal of Xi'an University of Architecture and Technology | Year: 2012

Large area rebound deformation due to excavation of loess foundation pit was modeled through conventional consolidation-rebound test in this paper, and deformation characteristics of soil in different depth were studied. The critical unloading ratio and ultimate unloading ratio were derived according to the unloading ratio-rebound ratio and unloading ratio-resilience modulus relationship, and the maximum depth of unloading influence area and strong rebound area could be estimated using these two ratios, which would provide theoretical basis for determining the rebound displacement of loess foundation pit. Finally, based on the former research, the maximum rebound depth, strong rebound area and total rebound displacement of a foundation pit in Xi'an was calculated, which were similar to the in-situ test results. This verified that the method given in this paper was feasible.


Meng L.,Chengdu University of Technology | Li T.,Chengdu University of Technology | Du Y.,China Railway Eryuan Engineering Group Co. | Huang Z.,Chengdu University of Technology | And 3 more authors.
Zhongguo Tiedao Kexue/China Railway Science | Year: 2016

In order to study the deformation and failure characteristics of phyllite under thermo-hydro-mechanical (THM) coupling, the conventional triaxial unloading tests were carried out for phyllite, the typical soft rock, under the conditions of high ground temperature, high seepage water pressure and high confining pressure. Taking the Gaoligong Mountain tunnel of Dali-Ruili Railway as an example, the numerical simulation of large deformation of phyllite tunnel under THM coupling was performed. According to experimental results and numerical simulation results, the large deformation mechanism of phyllite tunnel under THM coupling was discussed. Results show that high seepage water pressure and high ground temperature promote the growth of phyllite crack. The peak stress of phyllite is reduced by increasing seepage water pressure and ground temperature, and the influence of seepage water pressure is greater than that of ground temperature. Under THM coupling, the displacement of tunnel side wall is the greatest, the stress of arch springing is relatively concentrated, the seepage velocity of tunnel wall is the greatest, and the distribution of ground temperature is mainly controlled by the direction of groundwater seepage. The stress, displacement and seepage velocity of tunnel wall increase with the increase of ground temperature. On the basis of above analysis, the "H↔M, T↔H, T→M" coupling mode is established. The large deformation mechanisms of phyllite tunnel under THM coupling are as follows: high ground temperature will give rise to the initial thermal damage of surrounding rock; high seepage water pressure will promote surrounding rock softening and the further growth of its internal crack; when the secondary stress due to tunnel excavation exceeds the yield strength of surrounding rock, then the plastic flow surrounding rock is formed. © 2016, Editorial Department of China Railway Science. All right reserved.


Fang X.,Chengdu University of Technology | Li T.,Chengdu University of Technology | Ma H.,Northwest Research Institute of Engineering Investigations and Design | Wang F.,Chengdu University of Technology
Geotechnical Special Publication | Year: 2013

The attenuation plateau formed during radiation of dynamic compaction shockwave has a severe impact on construction work in loess backfill site and safety of buildings nearby. With essential targets of finding out reasons for attenuation plateau formation and providing basis for safe distance determination, geophysical prospecting was adopted in the test for in-depth investigation on the attenuation plateau characteristics of shockwave so as to provide basic data for attenuation law study of shockwave. Appropriate cut-off frequency was selected according to the test results and energy composition characteristics of elastic wave in semi-infinite soil. The shockwave energy was divided into body wave energy and surface wave energy in order to analyze energy attenuation characteristics of different waves. It is confirmed that the main reasons for attenuation plateau formation in the area were proportion and radiation characteristics of body wave energy. On this basis, staircase method was used to fit the radiation attenuation characteristics of dynamic compaction shockwave through subsection regression and compare with traditional fitting methods. The results showed that in close-distance and high-density dynamic compaction work, staircase method can be more accurate to mark out safe distance. © 2013 American Society of Civil Engineers.


Yunjun L.,Northwest Research Institute of Engineering Investigations and Design | Qianli X.,Northwest Research Institute of Engineering Investigations and Design
Applied Mechanics and Materials | Year: 2013

Highway landslide disaster is the main type of geological hazard in China, which causes great economic loss and casualty. According to the engineering experience, discrimination and criterion of highway landslide disaster is put forward in this paper on the basis of laws and types of highway landslide disaster, which includes nine big macroscopic discriminant criterion and five big microscopic discriminant criterion. On the basis of development process and stage, the development of landslide disaster is divided into three stages according to the practical needs: early embryonic stage, medium potential stage, late induced phase. To regional discriminant criterion of highway landslide disaster as the foundation, this paper presents the discriminant criterion of development for highway landslide disaster. It is hoped that the findings herein will provide science direction for temporal discriminant of highway landslide disaster. © (2013) Trans Tech Publications, Switzerland.


Cui G.-Q.,Xi'an University of Architecture and Technology | Liu Z.-R.,Xi'an University of Architecture and Technology | Ma C.-G.,Northwest Research Institute of Engineering Investigations and Design
Applied Mechanics and Materials | Year: 2013

Structure and anisotropy are two fundamental aspects of natural clays. They can't be ignored because of their significant influences on soil's strength and stress-strain behavior, etc. Therefore, anisotropic tensor and structural parameters are introduced in Modified Cam Clay Model which is only suitable for isotropic remolded clays, and evolution laws of them are given in this paper. Thus, an elasto-plastic constitutive model considering the influences of natural soil structure and anisotropy is established. Most parameters involved in this model have explicit physical meaning and are easily determined through geotechnical tests, which makes this model more flexible, practical and applicable to practical engineering. © (2013) Trans Tech Publications, Switzerland.


Liu K.,Northwest Research Institute of Engineering Investigations and Design | Zhao H.,Northwest Research Institute of Engineering Investigations and Design
Xi'an Jianzhu Keji Daxue Xuebao/Journal of Xi'an University of Architecture and Technology | Year: 2014

In order to ensure safety of deep foundation pit nearby the subway station in the construction process, the deformation of pile-anchor retaining structure nearby the subway station in the construction process is analyzed by numerical simulation method, and its stability is also analyzed. The study showed that the maximum lateral displacement of pit-retaining structure occurs at about 7m away from the top of the pit, and maximum lateral displacement is 13.4mm And the maximum surface subsidence occurs at about 4m away from the pit, and the largest settlement is 8.81mm. the pile-anchor retaining structure has good stability, and can effectively control the deformation of the pit during excavation. This background engineering deep foundation excavation does not affect the safety of the subway station.

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