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Liu R.D.,Xian University of Architecture and Technology | Zheng J.G.,China JK Institute of Engineering Investigation and Design | Li Z.Y.,CAS Zhengzhou Research Institute
Applied Mechanics and Materials | Year: 2013

A series of soil-structure shear tests was taken by self-made large single shear apparatus and the main factors affecting behavior of the interface are studied. It was shown that the deformation and mechanical properties are determined by the roughness of structural surface, particle size distribution and normal stress. The interface deformation includes the shear deformation of the soil near the structure due to the constraint of structural surface and the slipping deformation of soil-structure interface, they happen at the same time and interact each other. The thickness of the interface element is 4 to 5 times of the average particle diameter away from the structure surface. © (2013) Trans Tech Pudlications, Switzerland. Source

Liu R.-D.,Xian University of Technology | Zheng J.-G.,China JK Institute of Engineering Investigation and Design | Li Z.-Y.,CAS Zhengzhou Research Institute
Xi'an Jianzhu Keji Daxue Xuebao/Journal of Xi'an University of Architecture and Technology | Year: 2013

The contrast tests on the interface were conducted by self-made large single shear apparatus under different normal stress, where two gravel aggregates with different gradation and two structure surfaces with different roughness were used in the test, the influence of the maximum grain size and the test sample height to the results were also considered. The basic rules and influence factors of the interface's stress deformation between the structure and coarse aggregates were analyzed, and the solution of the parameters of the constitutive equation were given. The results show that the roughness of structural surface, particle size distribution and the normal stress have a great influence on the interface; that the thickness of the interface element is 4 to 5 times the average particle size. The shear deformation of the soil before yielding can be described with nonlinear elastic model, and the slip deformation of the interface element after yielding can be described with complete plastic theory. Source

Wang J.-J.,Xian University of Architecture and Technology | Deng J.-T.,China JK Institute of Engineering Investigation and Design | Wu S.-L.,China Metallurgical Group northwest Geotechnical Engineering
Applied Mechanics and Materials | Year: 2014

Compacted loss widely used in the construction, such as embankment, dam, foundation backfill and other projects. Influenced by rainfall factors, the moisture content of compacted loess often vary so the shear strength will also changed. This paper studies the shear strength parameters of compacted loess through direct shear tests. In the dry density under the same conditions, the cohesion, internal friction angle of compacted loess decreases with the increase of water content. Summed cohesion and water content showed a quadratic parabola and internal friction angle and water content was also found quadratic parabola; further considering the effects of water content and dry density of compacted loess got shear strength formula. Shear strength formula. © (2014) Trans Tech Publications, Switzerland. Source

Wang X.,Xian Jiaotong University | Tao W.,Xian Jiaotong University | Tao W.,China JK Institute of Engineering Investigation and Design | Xu Y.,University of Texas at Austin | And 2 more authors.
Atmospheric Environment | Year: 2014

Indoor phthalate levels were investigated in 28 buildings, including 14 office and 14 residential buildings in Xi'an, China. Phthalate esters in the gas-, particle-, and dust- phase were measured separately. Four phthalates including dimethyl phthalate (DMP), diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP) and di(2-ethylhexyl) phthalate (DEHP) were detected. The detection frequency of DnBP and DEHP was more than 90%. The concentrations of total phthalate esters ranged from 0.20 to 8.29μgm-3 for the gas- phase, from 0.09 to 14.77μgm-3 for the particle- phase and from 123 to 9504μgg-1 for the dust- phase. The individual phthalate with the highest concentrations of 6.17μgm-3, 7.97μgm-3 and 7228μgg-1 respectively for gas-, particle- and dust- phase in all investigated rooms is all DiBP. The median concentration of the gas- and particle-phase DiBP (0.52 and 0.72μgm-3) and dust-phase DEHP (582μgg-1) were the highest. It was also found that the average concentrations of individual phthalates in residential buildings were often higher than in office buildings, and correlation analysis indicated that DiBP, DnBP and DEHP might come from the same sources. Based on the gas- and particle-phase concentrations measured, the particle-air partition coefficients of phthalates were estimated, and their logarithm values were found to be linearly correlated with the logarithm values of their octanol-air partition coefficients. Finally, the total daily exposure to indoor phthalates in air and dust was calculated, and ranged from 2.6μgkg-1day-1 (for adults) to 7.4μgkg-1day-1 (for toddlers). © 2014 Elsevier Ltd. Source

Cao Z.,Zhejiang University | Cao Z.,Chalmers University of Technology | Cai Y.,Zhejiang University | Bostrom A.,Chalmers University of Technology | Zheng J.,China JK Institute of Engineering Investigation and Design
Journal of Sound and Vibration | Year: 2012

A semi-analytical model is proposed to investigate the screening efficiency of trenches to moving-load induced ground vibrations. The ground is modeled as a fully saturated poroelastic half-space governed by Biots dynamic poroelastic theory. The trenches are obtained by placing three rectangular elastic layers with appropriate width upon the poroelastic half-space. By Helmholtz decomposition, the displacement fields of the elastic layers are decomposed into three scalar potentials. Analytical solutions are obtained based on Fourier transform and Fourier series in the transformed domain. The time-domain results are obtained by the fast Fourier transform (FFT). The different performances of trenches on a saturated poroelastic half-space and a single-phase elastic half-space to the moving load-induced ground vibration are identified. It is found that the discrepancy of the screening efficiencies between the two models becomes significant when the load speed approaches the Rayleigh wave speed of the ground surface. Also, some parametric studies for the screening efficiency of the trench on the poroelastic half-space are presented. © 2011 Elsevier Ltd. All rights reserved. Source

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