Papers by Keyword: Soil

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Authors: Iveta Štyriaková, R. Hampl, I. Jech
Abstract: To examine the effects of organic and inorganic amendments on the degradation of petroleum hydrocarbons, we conducted a pilot-scale experiment during the winter and summer periods. Soil samples were analyzed periodically to determine the soil gas amount of volatile organic compound, carbon dioxide flux, consumption of O2 and indigenous bacterial numbers during bioremediation. The initial level of the most contaminated site (10 070 mg hydrocarbon kg-1 soil) was reduced successively to 4 800 mg kg-1 after 4 months and to 1 400 mg kg -1 after 6 months in ex-situ amended soils. The hydrocarbon-degrading microbial populations increased during the treatment as also did soil respiration. Both aerobic and methanogenic conditions appeared to be important at these sites. Methane concentration (500-23 000 ppm) and CO2 production (800-17 000 ppm) varied with the extent of contamination. The bioventing system used in this study aerated a wide area of soil. It was concluded that N and P availability within the organic and inorganic nutrients limited the biodegradation of hydrocarbon contamination. By combination of organic and inorganic amendments a 86% removal efficiency was achieved. Nutrient diffusion varied within the 3 m high decontamination biopile but was sufficient to promote bacterial proliferation in all layers.
713
Authors: Yuan Xue Liu, Zhong You Li, Jian Ting Zhou, Shu Guo Sun
Abstract: Set out from a basic idea that damage is a course of energy dissipation, a new damage variable is present. The damage variable is obtained for arbitrary strain state of soil according to the superimposing principle of compatible probability event for volumetric strain and shear strain. Through the analysis of a series of triaxial experimental results of structured soil, a new damage evaluation equation is put forward. The computation results tally with the experimental data show it is reasonable that this new damage variable and its evaluation law for structured soil.
257
Authors: Rafal Uliniarz
Abstract: The paper presents a reasonably advanced constitutive law for soil – a hybrid of the Modified Cam Clay and a new RU development. The Modified Cam Clay model is an isotropic hardening elasto – plastic model originated by Burland in 1967 [1] within the critical state soil mechanics. This model describes realistically mechanical soil behaviour in normal consolidation states. The other one is designed to ensure more adequate soil responses to reloading paths, particularly in the range of small strains. The RU+MCC model has been implemented in the FEM computer code Z_SOIL.pc. To test the influence of the small strain nonlinearity on soil – structure interaction as well as to exhibit the ability of the proposed model to simulate realistically this effect, a comparative study based on the FEM solution has been carried out. As a benchmark a trial loading test of strip footing was used.
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Authors: Huu Duc To, Sergio Andres Galindo-Torres, Alexander Scheuermann
Abstract: Granular soil as a porous medium consists of particles, touching each other and forming a solid skeleton with interconnected pores. The transfer of externally applied loads is in most cases not homogeneous, but takes place mostly in a limited number of particles creating so-called force chains. The assembly of force chains is frequently referred to the primary fabric of a soil. The knowledge of the primary fabric is of vital importance for the analysis of many soil behaviours as, for instance, in the assessment of suffusion. Most of the current numerical models, mostly based on a discrete element approach, generate an artificial soil specimen by creating particles randomly. Therefore, particle position is not under control at all, and as a consequence the influence from particle arrangement on the creation of the primary fabric is neglected. This paper presents a sequential packing method, which allows studying two different types of particle arrangements for a given and constant grain size distribution: (1) layer-wise, producing a layered structure and (2) discrete, leading to a rather homogeneous soil structure. The generated soil specimens are compacted using a discrete element model under oedometric boundary conditions and zero gravity to create force chains within the soil structure. These force chains are then analysed to determine the soil fraction contributing to the load transfer. The results of the study provide an evidence of the influence of the particle arrangements on the appearance of the soil skeleton and the fraction of particles involved.
489
Authors: Zeng Liang Gao, W. Hong, B. Xiong, W. Zheng, Y. Wu
520
Authors: Decio Lopes Cardoso, Talita Bassegio Kaminski, Francine Stelle Goldoni, Guilherme Irineu Venson, Camila Daiane Cancelier
Abstract: The soil is a brittle material compared to other engineering materials such as steel, concrete and wood. The clayey nature of the soils of western Paraná causes them to be chemically reactive towards certain compounds, thereby improving their engineering properties, especially its mechanical strength. The study involved treating the typical soil of the region with two residues from industrial and human activities: rice husk ash (RHA) at doses 0; 2.5; 5; 7.5 and 10%; and burned sewage sludge (BSS) at doses 0; 5; 10; 15 to 20%; in the dry soil mass. The test samples were compacted in Mini-MCV equipment and broken in triaxial compression tests of consolidated undrained type, with confining pressures of 25; 50 and 100 kPa. The results showed that both the RHA change dramatically as the BSS which passes viscoelastic plastic-linear mechanical behavior of the composites. There was a significant increase in deviator tension and elasticity modulus, implying a gain in strength and stiffness of the composite compared to the natural soil. The most striking effect was observed in the RHA cohesion parameter; while the substantial effect of BSS was observed in the interparticles friction angle. These results suggest that RHA promoted the formation of new products filling the pore space of the composite, changing the clayey material in a nature of a continuum, while the BSS promoted a substantial aggregation of the particles, wherein the soil reinforcement transformed clay in a particulate material coarser grain size.
400
Authors: Yi Wang, Xiao Yan Ding, Hao Yang, Ji Wei Hu, Fan Jiang, Hai Long Chen
Abstract: Both single pollution index and integrated pollution index methods were employed in the present research to assess the heavy metals pollution of soil in the three Rosa roxburghii Tratt Planting Bases (located in Qianxi County and Qixingguan region in Bijie, Longli County in Qiannan), the baseline values of heavy metals in soils in Guizhou Province, Environmental Quality Standard for Soils (GB15618-1995) and Conditions of Green Food-tech0.nical Environmental Quality for Production Area (NY/T391-2000 and GB/T18407.1-2001) were applied as references. National Food Safety Standard-Contaminants in foods was applied to evaluate Rosa roxburghii Tratt fruits. The results suggest that the studied soil samples conformed to Environmental Quality Second Level Standard for Soils and Green Food-technical Conditions. The overall quality of the soil conditions was uncontaminated, but point source pollution phenomenon existed. Hg, Pb and Cu pollution were the main factors contributing to the rise in comprehensive pollution index from the three Rosa roxburghii Tratt Planting bases. It was found that levels of As and Cu did not exceed the limited standard of the soil,while Hg, Cr, Cd and Pb exceeded the standard in different degrees in studied Rosa roxburghii Tratt planting bases. The rates of excessive quota of Hg, Cr, Cd and Pb in the studied Rosa roxburghii Tratt fruits was 6.67%, 13.33%, 73.33% and 100%, respectively. The mean accumulation coefficient of Cd for Rosa roxburghii Tratt fruits was up to 1.20. The mean accumulation coefficients for concerned heavy metals were in the order of Cd > Cu > Pb > Hg > As> Cr. The relationships between concentrations of heavy metals in soil, leaf and stem samples were weak. However, significant correlations were found between concentrations of As in soil and leaf samples (r = 0.928), and concentrations of Cr between in soil samples and Cr in leaf samples (r = 0.733).
88
Authors: Chun Rong Zhang, Chun Jin Zhang, Zheng Long Wu, Zong Jun Gao
Abstract: To study the impact of atmospheric Cd exerts on the soil accumulated of Qingdao urban area, atmospheric dust and soil samples are collected and analyzed. Based on these tested samples, this paper firstly analyzed the geochemistry characters of Cd in atmospheric dusts and soils using the statistic analysis method. Then according to the time accumulation model about the influence of Cd exerts on soil, this paper predicates the influence that atmospheric Cd in dust exerts on soil 20 years later. Analysis results show that atmospheric Cd has great influence on the accumulated soil. For example, it can cause the deterioration of soils quality. Therefore, to prevent soil from Cd pollution, the detection and control of atmospheric Cd should be strengthen.
200
Authors: Yoshiharu Morimoto, Motoharu Fujigaki, Akihiro Masaya, Hiroyuki Kondo, Tatsuya Inuzuka
Abstract: Sampling moiré method is useful to measure shape, displacement and strain distributions of multi-functional materials and structures. When a specimen grating pattern on an object is recorded by a digital camera, a moiré fringe pattern is obtained by sampling the digitized grating image with a constant pixel pitch. The method can analyze phase values from one image of a grating pattern. By using this sampling moiré method, the displacement measurement of land is analyzed to develop a landslide prediction system. The theory and the application for measuring the displacement of land are shown in this paper.
1731
Authors: Dong Sheng Wang, Yu Chao, Ting Zhang
Abstract: Oxytetracycline (OTC) is one of the extensive use antibiotics in livestock. Untreated waste of livestock and poultry breeding discharged into the soil or applied to the soil, directly, lead to pollution of soil in antibiotics. Current antibiotics pollutes caused problem to cause social attention more and more. As soil is the main destination of antibiotics like other pollutants, the antibiotics would eventually be accumulated in the soil when they entered the environment, researching antibiotics in soil migration and diffusion in water environment is important. To analyze environmental risks in antibiotics, and to provide reference basis for antibiotic pollution control, OTC in soil adsorption process and mechanism are conducted. Research showed that first-order kinetic equation model, double constant equation model, and parabolic equation can describe the adsorption process of OTC in soil. Under PH=7 condition, the strongest adsorption and the maximum adsorption capacity are appeared. Adsorption of OTC in soil has a certain mobility, and there are certain security threats in surface water and groundwater environment.
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