scholarly journals Experimental Study on Strength Influencing Factors of Calcareous Nodule Soil in Northern Jiangsu

2021 ◽  
Author(s):  
Xiaolong Wang ◽  
Jianling Gu ◽  
Song Xu ◽  
Shengdong Gu
Keyword(s):  
Particle Size ◽  
Water Content ◽  
Soil Layer ◽  
Physical And Mechanical Properties ◽  
Triaxial Tests ◽  
Long Time ◽  
Confining Pressures ◽  
Calcareous Concretion ◽  
Time Required ◽  
The Impact

The physical and mechanical properties of calcareous concretion soil depend largely on the shape, size and distribution of calcareous concretion soil besides the impact of soil layer. Due to the long time required for clay saturation, consolidation, and shearing, as well as the tedious sample preparation, larger triaxial tests of calcareous nodules have not been carried out. In this chapter, based on the medium triaxial test of calcareous nodules, the strength characteristics of remolded soil samples under different confining pressures are studied. By controlling parameters such as calcareous nodules particle size and water content, the impact of different test conditions on the strength of calcareous nodules is analysed, and the variation rule is analysed. It is concluded that the impact of nodular particle size on soil strength is not obvious at 20% nodular content. The impact of different water content on the strength of soil is more regular, showing hardening characteristics, in line with the natural law.

scholarly journals Physical and Mechanical Properties of a Bulk Lightweight Concrete with Expanded Polystyrene (EPS) Beads and Soft Marine Clay

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1662 ◽  
Author(s):  
Jianguo Wang ◽  
Bowen Hu ◽  
Jia Hwei Soon
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cement Content ◽  
Mass Density ◽  
Physical And Mechanical Properties ◽  
Confining Pressure ◽  
Expanded Polystyrene ◽  
Triaxial Tests ◽  
Filling Material ◽  
Confining Pressures

The variation of physical and mechanical properties of the lightweight bulk filling material with cement and expanded polystyrene (EPS) beads contents under different confining pressures is important to construction and geotechnical applications. In this study, a lightweight bulk filling material was firstly fabricated with Singapore marine clay, ordinary Portland cement and EPS. Then, the influences of EPS beads content, cement content, curing time and confining pressure on the mass density, stress–strain behavior and compressive strength of this lightweight bulk filling material were investigated by unconsolidated and undrained (UU) triaxial tests. In these tests, the mass ratios of EPS beads to dry clay (E/S) were 0%, 0.5%, 1%, 2%, and 4% and the mass ratios of cement to dry clay (C/S) were 10% and 15%. Thirdly, a series of UU triaxial tests were performed at a confining pressure of 0 kPa, 50 kPa, 100 kPa, and 150 kPa after three curing days, seven curing days, and 28 curing days. The results show that the mass density of this lightweight bulk filling material was mainly controlled by the E/S ratio. Its mass density decreased by 55.6% for the C/S ratio 10% and 54.9% for the C/S ratio 15% when the E/S ratio increased from 0% to 4% after three curing days. Shear failure more easily occurred in the specimens with higher cement content and lower confining pressure. The relationships between compressive strength and mass density or failure strain could be quantified by the power function. Increasing cement content and reducing EPS beads content will increase mass density and compressive strength of this lightweight bulk filling material. The compressive strength with curing time can be expressed by a logarithmic function with fitting correlation coefficient ranging from 0.83 to 0.97 for five confining pressures. These empirical formulae will be useful for the estimation of physical and mechanical properties of lightweight concretes in engineering application.

scholarly journals A Review of the Multi-Physical Characteristics of Plant Aggregates and Their Effects on the Properties of Plant-Based Concrete

2021 ◽  
Vol 03 (02) ◽  
pp. 1-1
Author(s):  
Herinjaka Haga Ratsimbazafy ◽  
◽  
Aurélie Laborel-Préneron ◽  
Camille Magniont ◽  
Philippe Evon ◽  
...  
Keyword(s):  
Particle Size ◽  
Building Materials ◽  
Physical And Mechanical Properties ◽  
Absorption Capacity ◽  
Construction Sector ◽  
Characterization Methods ◽  
Formulation Parameters ◽  
Hemp Shiv ◽  
Different Origins ◽  
The Impact

The use of plant aggregates obtained from agricultural co-products mixed with mineral binders to form eco-friendly insulating building materials has been initiated for a few years to bring environmentally friendly solutions to the construction sector. Several studies on different agro-resources have already been carried out, providing various information about the properties of plant aggregates and plant-based concrete. However, the characteristics of the agricultural co-product, which allow it to qualify as a plant aggregate for plant-based concrete, are not yet very clear despite the multitude of data, especially on hemp concrete. Therefore, it is important to gather numerous but very disparate pieces of information available in the literature concerning the properties of plant aggregates and their correlations with composites. This review is based on the results of 120 articles and aims to identify the characterization methods and the multi-physical properties of plant aggregates affecting those of plant-based concrete and to propose additional factors that could influence the properties of the composites. A total of 18 plant aggregates of different origins used for plant-based concrete have been listed in the literature. In France, hemp shiv is the most studied one, but its quantity is quite low unlike cereal or oilseed straws and wood transformation residues. With the existence of several characterization methods, properties like microstructure, particle size distribution, bulk density, water absorption capacity, and chemical composition of aggregates are easily and frequently determined. In contrast, data on the apparent density of particles, the skeleton density, and the hygro-thermal properties of aggregates are rare. The particle size, density, and porosity have been identified as important parameters influencing the properties of the composites. Other parameters related to the behavior of the aggregates under wet compaction and compression of their stacking can also predict the physical and mechanical properties of the obtained plant-based concrete. Dosages of the constituents should be preferred as formulation parameters for future studies assessing the impact of the aggregate properties on the composites.

scholarly journals Effect of Different Temperature-Controlled Ultrasound on the Physical and Functional Properties of Micellar Casein Concentrate

Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2673
Author(s):  
Bong Song ◽  
Yumeng Zhang ◽  
Baojia Yang ◽  
Panpan Zhu ◽  
Xiaoyang Pang ◽  
...  
Keyword(s):  
Particle Size ◽  
Functional Properties ◽  
Calcium Content ◽  
Unstable State ◽  
Pseudoplastic Fluid ◽  
Micellar Casein ◽  
Long Time ◽  
Soluble Calcium ◽  
Temperature Controlled ◽  
The Impact

Micellar casein concentrate (MCC) is a novel dairy ingredient with high protein content. However, its poor functional properties impair its potential for further application, highlighting the importance of using innovative processing methods to produce modified MCC, such as ultrasound (US). This work investigated the impact of US on the physical and functional properties of MCC under temperature-controlled and -uncontrolled conditions for different time intervals. Under temperature-controlled ultrasound (TC-US) treatment, a reduction was found in the supernatant particle size of casein micelles. Soluble calcium content and hydrophobicity increased following ultrasound treatment at 20 °C, resulting in a remarkable improvement in emulsification. However, long-time ultrasonication led to an unstable state, causing the MCC solutions to show shear thinning behavior (pseudoplastic fluid). Compared with 50 °C temperature-controlled ultrasonication, ultrasonication at 20 °C had a greater influence on particle size, viscosity and hydrophobicity. These findings indicate that 20 °C TC-US could be a promising technology for the modification of MCC.

scholarly journals Study on some fundamental factors affecting the static liquefaction of sand

2020 ◽  
Vol 61 (HTCS6) ◽  
pp. 40-47
Author(s):  
Kien Trung Nguyen ◽  
Thang Kim Nguyen ◽  
Ha Quang Ta ◽  
Huy Quang Dang ◽  
Keyword(s):  
Significant Influence ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Liquefaction Resistance ◽  
Factors Affecting ◽  
Static Liquefaction ◽  
The World ◽  
Long Time ◽  
Confining Pressures ◽  
Undrained Conditions

Static liquefaction of soil is a hazard that has caused a lot of damage to humans. Therefore, this phenomenon has been studied for a long time over the world, nevertheless, research on this issue in Vietnam is still limited. This paper presents the results of several triaxial tests under undrained conditions to evaluate the influence of some fundamental factors on the static liquefaction of Fontainebleau sand. The results show that the relative density and the confining pressure have a significant influence on the static liquefaction of the sand. When the density of the sand increases, the liquefaction resistance of the sand increases, until a certain limit, the sand changes from liquefaction behavior to dilatancybehavior with a decrease in pore pressure and an increase in mean effective stress. When the test is carried out at different confining pressures, the greater the confining pressure, the higher the liquefaction resistance.

scholarly journals The Permeability of Granite Weathering Soil in Tanjungpinang, Bintan Island, Indonesia

2020 ◽  
Vol 5 (3) ◽  
pp. 145-152
Author(s):  
Fery Erawan ◽  
Emi Sukiyah ◽  
Johanes Hutabarat ◽  
Adjat Sudradjat
Keyword(s):  
Mechanical Properties ◽  
Clay Mineral ◽  
Soil Analysis ◽  
Soil Layer ◽  
Physical And Mechanical Properties ◽  
Undisturbed Soil ◽  
Dominant Type ◽  
Flat Terrain ◽  
The Impact ◽  
Properties Of Soil

Bintan Island is a part of Riau Islands Province. On this island, the capital city is Tanjungpinang. The compliance of public facilities such as landfill waste is a priority in this city. Landfill design that suitable in this area is a sanitary landfill system. The soil layer uses to cover the waste in this landfill system. The closure did gradually avoid the disruption of waste processing. The type of soil for its landfill cover has to be able to control the leachate. It controlled by the permeability of the soil. The methods used in this study are the analysis of the physical and mechanical properties of soil. Rock and soil samples are obtained systematically through trenching. Sampling-based on changes in physical properties of soil that reflect its mechanical properties. A probabilistic approach used to solve the problems and to get accurate results. The geomorphology of the study area divided into four units. They are very flat terrain, flat terrain, slightly steep hills, and steep hills. The sample used for the study is undisturbed soil. Analysis of the physical and mechanical properties of soil shows the types of soil, such as SW, GM, MH-OH, and CH. However, MH is the most dominant type of soil. Each of the soil types represents a certain degree of weathering. The degree of weathering in the study area varies from the III degree to VI degrees. Rocks are weathering form clay mineral, which compiles the soil. Clay mineral in the soil layer is varied from quartz, illite, kaolinite, gibbsite, goethite, and hematite—the impact of the swelling of clay. The swelling of clay in the study area ranged from low to high. The properties and composition of the soil are affected by the permeability value.

Influence of infiltration on Babaoliao shallow landslide in Taiwan using hydro-mechanical coupled model

2020 ◽  
Author(s):  
Ya-Sin Yang ◽  
Hsin-Fu Yeh
Keyword(s):  
Slope Stability ◽  
Water Content ◽  
Soil Layer ◽  
Coupled Model ◽  
Shallow Landslide ◽  
Residual Soil ◽  
Wetting Front ◽  
Element Analysis ◽  
Unstable Slope ◽  
The Impact

<p>Babaoliao landslide is located in Chiayi County of Taiwan. The geological drilling and core interpretation in previous investigation showed that exist 1 to 2 meter depths of residual soil layer above the bedrock. In this area, shallow landslides frequently occur due to the intense rainfall events. An understanding of the hydro-mechanical change under rainfall infiltration within hillslope is critical to capture the slope stability. This study used hydro-mechanical coupled model and finite element analysis to compute the field water content and stress suction, and then assess the field slope stability based on theory of local of factor. Results showed the response of internal hydraulic behavior distribution is related to terrain and the depths of bedrock. The impact of rainfall on slope stability concentrated in shallow residual soil area, since higher permeability of soil cause rainfall infiltrate into hillslope easily and form lateral flow paths, thus limiting the depths of wetting front. The discontinuity of water content distribution within hillslope may accelerate the change of hydro-mechanical behavior and unstable slope development in the hillslope. This study demonstrated the varied distribution of water content, suction stress and LFS over time and space and got the insight into the relativity unstable range of the shallow slope affected by rainfall event.</p>

Experimental Study on Adsorption Capacity of Natural Gas Odorant Tetrahydrothiophene in Soil and Relevant Influencing Factors

2014 ◽  
Vol 1044-1045 ◽  
pp. 327-331
Author(s):  
Yu Shu Xie ◽  
Mo Dan ◽  
Bing Xue Song ◽  
Wei Yao
Keyword(s):  
Particle Size ◽  
Natural Gas ◽  
Water Content ◽  
Adsorption Capacity ◽  
Gas Chromatography Mass Spectrometry ◽  
Gas Leakage ◽  
Initial Stage ◽  
City Gas ◽  
The Impact ◽  
Properties Of Soil

According to the practice of city gas odorization, the technological thought that the diffusion behavior of natural gas in soil was indirectly reflected by the adsorption capacity of tetrahydrothiophene (THT) as an odorant of natural gas in soil was put forward and explored. The adsorbed amount of THT in soil samples by gas chromatography-mass spectrometry (GS-MS) with purge and trap was determined. The impact of four parameters (namely gas leakage, water content, particle size and texture of the soil) on the adsorption properties of soil was then quantitatively analyzed. The experimental results showed that at initial stage of adsorption, the adsorption capacity of THT in soil sample was linear positively correlated with gas leakage and was negatively correlated with water content of the soil and there were no significant differences between particle size and texture of the soil and the amount of THT.

scholarly journals Mechanical Mechanism of Water Injection to Enhance the Stability of Soft Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Chuanqi Zhu ◽  
Hao Fan ◽  
Wanrong Liu ◽  
Shaobo Li
Keyword(s):  
Particle Size ◽  
Water Content ◽  
Liquid Bridge ◽  
Capillary Tube ◽  
Water Injection ◽  
Physical And Mechanical Properties ◽  
Point Load ◽  
Displacement Curve ◽  
Angle Of Internal Friction ◽  
Soft Coal

The physical and mechanical properties of soft coal body constitute one of the most important factors inducing coal wall spalling. In order to explore the mechanical essence of coal instability disaster and stability enhancement of water injection, the 7# coal in Huainan mining area is taken as the research object. Firstly, the distribution characteristics of coal particle size, point-load strength, original water content, microstructure characteristics, and shear strength of coal under different water contents are measured by laboratory tests. Then, based on the test results, the cementation morphology and force evolution law of granular coal water in coal body are analyzed using liquid bridge theory. The results show the following: (1) With the increase of particle size, the mass ratio of granular coal increases gradually. The percentage of particle coal with particle size less than 2.5 mm accounts for 47.157%, fractal dimension is 2.172, and uniaxial compressive strength and tensile strength are 3.822 MPa and 0.165 MPa, respectively. (2) The coal body is dry (the original moisture content is 1.336%), containing a large number of loose particles, pores, fissures, and other microfabrics. This “low water content and multiporosity” feature is the essential reason for its low strength, fragmentation, and instability and disaster. (3) In the process of water content increasing from 0.966% to 26.580%, the shear stress-displacement curve of coal body gradually changes from softening type to hardening type, and the failure type transitions from brittleness to ductility. The cohesive force increases first and then decreases, while the angle of internal friction almost has no change. (4) After reasonable water injection, the shape of liquid bridge in coal body changes into capillary tube, and the liquid bridge force reaches the maximum value, which transforms from a highly unstable bulk to a stable continuum. The research results have important theoretical significance and practical value for the safe and efficient mining of soft coal seams.

scholarly journals Investigating the Influence of Biochar Particle Size and Depth of Placement on Nitrous Oxide (N2O) Emissions from Simulated Urine Patches

Agriculture ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 175
Author(s):  
Ainul Mahmud ◽  
Marta Camps-Arbestain ◽  
Mike Hedley
Keyword(s):  
Particle Size ◽  
Nitrous Oxide ◽  
Soil Column ◽  
Soil Layer ◽  
Nitrous Oxide Emissions ◽  
N2o Emissions ◽  
Top Soil ◽  
The Impact ◽  
Soil Inversion

The use of biochar reduces nitrous oxide (N2O) emissions from soils under specific conditions yet the mechanisms through which interactions occur are not fully understood. The objectives of this glasshouse study were to investigate the effect of (i) biochar particle size, and (ii) the impact of soil inversion—through simulated mouldboard ploughing—on N2O emissions from soils to which cattle urine was applied. Pine biochar (550 °C) with two different particle sizes (<2 mm and >4 mm) was mixed either into the top soil layer at the original 0–10 cm depth in the soil column or at 10–20 cm depth by inverting the top soil to simulate ploughing. Nitrous oxide emissions were monitored for every two to three days, up to seven weeks during the summer trial and measurements were repeated during the autumn trial. We found that the use of large particle size biochar in the inverted soil had significant impact on increasing the cumulative N2O emissions in autumn trial, possibly through changes in the water hydraulic conductivity of the soil column and increased water retention at the boundary between soil layers. This study thus highlights the importance of the role of biochar particle size and the method of biochar placement on soil physical properties and the implications of these on N2O emissions.

scholarly journals Changes in soil-water content and heat transport under different simulated systems of drip irrigation in gravel-mulched fields

2021 ◽  
Author(s):  
Wenju Zhao ◽  
Yali Wang ◽  
Junhong Hu ◽  
Zongli Li
Keyword(s):  
Soil Temperature ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Heat Transport ◽  
Air Temperature ◽  
Drip Irrigation ◽  
Soil Layer ◽  
Irrigation Frequency ◽  
The Impact

Abstract Gravel mulching is an ancient mulching system with a history of more than 300 years in China. To explore the changes of soil-water content (SWC) and heat transport in watermelon gravel-mulched fields under the drip irrigation, we simulated three irrigation quotas (W1, 180 m3/hm2; W2, 270 m3/hm2; and W3, 360 m3/hm2) and three irrigation frequencies (F1, three times; F2, six times; and F3, nine times) based on HYDRUS-2D. The results indicated that peak SWC increased with irrigation quota. The range of fluctuation of SWC decreased as irrigation frequency increased. The temperature of the 0–40 cm soil layer varied with air temperature, but the range of fluctuation decreased with depth. Irrigation affected the distribution of soil water, increased soil heat capacity, and reduced the impact of air temperature on soil temperature, thus delaying the impact of air temperature on soil temperature. High-frequency drip irrigation could therefore effectively improve SWC, reduce water stress during the period of watermelon growth, and effectively delay the effect of air temperature on soil temperature, providing a theoretical basis for developing reasonable irrigation strategies and regulating soil water and heat in gravel-mulched fields.

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