scholarly journals Study on Mechanical and Ecological Properties of Fly Ash Substrate for Ecological Slope Protection

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Juan Wan ◽  
Jun Zhu ◽  
Henglin Xiao ◽  
Qiang Ma
Keyword(s):  
Shear Strength ◽  
Fly Ash ◽  
Moisture Content ◽  
Friction Angle ◽  
Ash Content ◽  
Class V ◽  
Ecological Requirements ◽  
Msw Incineration ◽  
Standard Limit ◽  
Root Content

In order to realize the resource utilization of fly ash, a kind of ecological slope protection substrate was prepared by mixing fly ash produced by MSW incineration into slope protection soil. Through the direct shear test and a leaching experiment on ion pollutants, the influence that shear strength of the substrate changed with root content, ash content, and moisture content and the ecological effects of leach liquor were investigated. The results showed the following: (1) When the optimum moisture content is about 24.9%, the shear strength of the substrate is the maximum. (2) Fly ash can improve the shear strength of the soil, which can reach 1.67 times as much as that of plain soil, and the optimum content of fly ash is 5%–6.7%. (3) The root system can increase the cohesion and internal friction angle of the substrate soil but mainly increases the cohesion of the substrate soil. (4) Plants grow taller in ash-mixed soil than in plain soil. (5) When the fly ash content is 20%, the ion concentrations of Cl, Cu, and Zn are the highest: 220.7, 0.153, and 1.526 mg/L, respectively. All of them are lower than the standard limit of class V water and gradually decrease with time. Therefore, the leaching liquid will not cause environmental pollution and meet the ecological requirements.

scholarly journals Improvement of the Salinized Soil Properties of Fly Ash by Freeze-Thaw Cycles: An Impact Test Study

2021 ◽  
Vol 13 (5) ◽  
pp. 2908
Author(s):  
Zhuo Cheng ◽  
Gaohang Cui ◽  
Zheng Yang ◽  
Haohang Gang ◽  
Zening Gao ◽  
...  
Keyword(s):  
Shear Strength ◽  
Fly Ash ◽  
Internal Friction ◽  
Unconfined Compressive Strength ◽  
Saline Soil ◽  
Friction Angle ◽  
Ash Content ◽  
Internal Friction Angle ◽  
Freeze Thaw ◽  
Salinized Soil

To explore the mechanism of the microstructural change in salinized soil under freeze-thaw cycles and the strength characteristics of subgrade salinized soil improved by fly ash, an unconfined compressive test, a triaxial shear test, and a scanning electron microscopy test were carried out using salinized soil samples with different fly ash contents along the Suihua to Daqing expressway in China. The results showed that after several freeze-thaw cycles, the unconfined compressive strength, triaxial shear strength, cohesion, and internal friction angle of saline soil showed a decreasing trend. With an increase in the fly ash content, the internal friction angle, cohesion, unconfined compressive strength, and shear strength of the improved saline soil first increased and then decreased. When the fly ash content was 15%, the mechanical indexes, such as cohesion and the internal friction angle, reached the maximum value. Microscopic test results showed that the freeze-thaw cycle will lead to an increase in the proportion of pores and cracks, an increase in the average pore size, and a loosening of the soil structure. The addition of fly ash can fill the soil pores, improve the microstructure of the soil, increase the cohesive force of the soil particles, and improve the overall strength of the soil. Fly ash (15%) can be added to subgrade soil in the process of subgrade construction in the Suihua-Daqing expressway area to improve the shear strength and the resistance to freezing and thawing cycles. These research results are conducive to promoting the comprehensive utilization of fly ash, improving the utilization rate of resources, and promoting sustainable development, thus providing a reference for the design and construction of saline soil roadbed engineering in seasonal frozen areas and the development and construction of saline land belts in seasonal and winter areas.

scholarly journals Quantitative Analysis of the Relationship Between Shear Strength and Fractal Dimension of Solidified Dredger Fill with Different Fly Ash Content Under Monotonic Shear

2018 ◽  
Vol 25 (s2) ◽  
pp. 132-138 ◽  
Author(s):  
Yang Shuai ◽  
Liu Wenbai ◽  
Liu Hongwei
Keyword(s):  
Shear Strength ◽  
Fractal Dimension ◽  
Fly Ash ◽  
Particle Surface ◽  
Fractal Dimensions ◽  
Friction Angle ◽  
Ash Content ◽  
Strength Index ◽  
Dredger Fill ◽  
The Relationship

Abstract The dredger fill of Shanghai Hengsha Island Dongtan is solidified by curing agents with different fly ash content, and the shear strength index of solidified dredger fill is measured by the direct shear test. The microscopic images of solidified dredger fill are obtained by using SEM. The microscopic images are processed and analyzed by using IPP, and the fractal dimension including particle size fractal dimension Dps, aperture fractal dimension Dbs and particle surface fractal dimension Dpr is calculated by fractal theory. The quantitative analysis of the relationship between shear strength index and fractal dimension of solidified dredger fill is done. The research results show that the internal friction angle and the cohesion are closely related to the fly ash content λ and the curing period T, and the addition of fly ash can improve the effect of curing agent; There is no obvious linear relationship between the internal friction angle and the three fractal dimensions; The smaller particle surface fractal dimension Dpr and particle size fractal dimension Dps, the larger aperture fractal dimension Dbs, the greater the cohesion, and the cohesion has a good linear relationship with three fractal dimensions, and the correlation coefficient R2 is above 0.91.

Characterization of Shear Strength and Interface Friction of Organic Soil

2020 ◽  
Vol 857 ◽  
pp. 203-211
Author(s):  
Majid Hamed ◽  
Waleed S. Sidik ◽  
Hanifi Canakci ◽  
Fatih Celik ◽  
Romel N. Georgees
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Internal Friction ◽  
Moisture Content ◽  
Water Content ◽  
Friction Angle ◽  
Structural Materials ◽  
Organic Soil ◽  
Internal Friction Angle ◽  
Interface Friction

This study was undertaken to investigate some specific problems that limit a safe design and construction of structures on problematic soils. An experimental study was carried out to examine the influence of loading rate and moisture content on shear strength of organic soil. Influece of moisture content on interface friction between organic soil and structural materials was also attempted. A commonly used soil in Iraq was prepared at varying moisture contents of 39%, 57% and 75%. The experimental results showed that the increase in water content will decrease the shear stress and the internal friction angle. An increase of the shearing rate was found to decrease the shear stress and internal friction angle for all percetanges of water contents. Further, direct shear tests were carried out to detect the interface shear stress behavior between organic soil and structural materials. The results revealed that the increase in water content was shown to have significant negetavie effects on the interface internal friction and angle shear strength.

scholarly journals Shear Strength Characterization of Bauxite Deposits in Kuantan, East Coast Malaysia

2019 ◽  
Vol 8 (3S3) ◽  
pp. 404-407
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
East Coast ◽  
Field Performance ◽  
Friction Angle ◽  
Parent Rock ◽  
Index Tests ◽  
Strength Characterization ◽  
The Relationship

Engineering characterization which are useful for "temperate" zone soils usually fail to predict the field performance of bauxitic soils, because the index tests upon which the characterization are based are not always reproducible for bauxitic soils. Fifteen (15) bauxitic soil of undisturbed and disturbed samples from 3 distinct sites in Kuantan, all derived from basalt parent rock but representing various stages of weathering were subjected to engineering and mineralogic tests. Values for cohesion and friction angles are evaluated. Soils from Semambu has the highest moisture content of 33.27%, the cohesion value is however lower compared to Bukit Goh which has moisture content of 21.74%. Study are further done to discover the relationship with cohesion and friction angles. Thus, by measuring the cohesion and friction angle can evaluate the performance of bauxite shear strength.

The Strength of Fly Ash-Bottom Ash (FA-BA) Mixtures as Backfill Material in Ground Improvement Works

2013 ◽  
Vol 465-466 ◽  
pp. 937-943
Author(s):  
Abd Rahim bin Hj. Awang ◽  
Wan Hilmi bin Wan Mansor ◽  
Ahmad Yusri Bin Mohamad
Keyword(s):  
Shear Strength ◽  
Fly Ash ◽  
Specific Gravity ◽  
Ground Improvement ◽  
Bottom Ash ◽  
Friction Angle ◽  
Soil Improvement ◽  
Geotechnical Properties ◽  
Raw Material ◽  
Fa Composition

In Malaysia, coal has been used as a raw material to generate electricity since 1988. In the past, most of the wastage of coal burning especially the bottom ash was not managed properly as it was dumped in the waste pond and accumulated drastically. This research has been conducted to explore the physical characteristic and geotechnical properties of fly ash-bottom ash (FA-BA) mixtures that consist of 30% FA, 50% FA, 70% FA and 90% FA by weight. The physical characteristics, that include the specific gravity, particle size distribution and compaction, were tested for each mixture without any curing. However, the geotechnical properties of the mixtures that include the permeability and shear strength had been studied at various curing periods (0, 14 and 28 days) to review the effect of time on the geotechnical properties of the mixtures. The results show that mixtures with higher FA composition have lower value of specific gravity, well-graded, and need less moisture to be compacted efficiently compared to those mixtures with lower FA composition. The results also show that mixtures with higher FA composition have less drainage characteristics but can be improved by prolonging the curing period. The maximum shear strength was obtained at mixture with 50%FA and the value increased with curing periods. The friction angle obtained ranged from 270to 370. It is also found that the mixtures with lower FA composition are more compressible compared to the mixtures with higher FA composition. The results obtained could be used by others to determine the suitability of different FA-BA mixtures for various usage in Geotechnical Engineering work such as for soil improvement work in weak soils or as backfill materials in embankment construction.

Study on Shear Strength Experiments Base on the Modified Direct Shear Apparatus for Unsaturated Soils

2013 ◽  
Vol 438-439 ◽  
pp. 1176-1180 ◽  
Author(s):  
Gao Feng Chen ◽  
Ying Fa Lv ◽  
Zhi Huai Huang ◽  
Yan Chang
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Moisture Content ◽  
Friction Angle ◽  
Soil Samples ◽  
Direct Shear ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
General Internal ◽  
Direct Shear Apparatus

The unconsolidated-undrained fast shear tests of saturated-unsaturated remolded soil samples under different moisture content which is 1.1%, 10.1%, 14.9%, 19.9%, 24.2%, 29.9%, 37.7% respectively, and normal stress which is 50kPa, 100kPa, 200kPa, 300kPa, 400kPa respectively, were studied by the modified SDJ-1-type strain direct shear apparatus and U.S. Lab VIEW data acquisition system. The shear strength parameters of unsaturated soil samples, i.e. general cohesion and general internal friction angle were obtained based on Mohr-Coulomb strength theory. The test results showed that the general cohesion firstly increased and then reduced with the moisture content increasing, and the general internal friction angle increased with the moisture content decreasing. The function between the general shear strength parameters and the moisture content was studied. The concept of general shear strength parameters was proposed in the paper, and would provide a simple and practical method to obtain the strength parameters for engineering practice.

scholarly journals SIFAT-SIFAT MEKANIK MATERIAL KOMPOSIT BERBAHAN DASAR FLY ASH DAN PASIR HALUS

2020 ◽  
Vol 12 (1) ◽  
pp. 1
Author(s):  
La Ode Muhaimin ◽  
Minson Simatupang
Keyword(s):  
Compressive Strength ◽  
Composite Material ◽  
Shear Strength ◽  
Fly Ash ◽  
Soil Stabilization ◽  
Compressive Strain ◽  
Fine Sand ◽  
Ash Content ◽  
Attractive Alternative ◽  
Curing Period

Soil stabilization using fly ash is an attractive alternative to be developed. Besides reducing industrial waste, it is also economical in terms of costs. With the presence of water, the lime contained in fly ash would be decomposed and undergone a cementation process and a pozolan reaction which would bind the sand grains. In this study, the effect of fly ash content and curing period on the amount of compressive strength and shear strength was observed using an unconfined compressive and direct shear test, respectively. The stress-strain relationships due to shear loads between sand without fly ash and sand with fly ash were compared to see an increase in shear strength due to the addition of fly ash. The results show that the unconfined compressive strength and shear strength of the composite material increase with the addition of fly ash and curing period. But the opposite happened in compressive strain. It was confirmed that the strain to achieve maximum compressive strength decreased with increasing fly ash content and curing period. The fly ash bond was getting brittle with the increasing compressive strength of the composite material made from fly ash and fine sand.

scholarly journals Influence of Organic Matter Content on Engineering Properties of Clays

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yue Gui ◽  
Qiumin Zhang ◽  
Xiaqiang Qin ◽  
Jianfei Wang
Keyword(s):  
Organic Matter ◽  
Shear Strength ◽  
Moisture Content ◽  
Void Ratio ◽  
Clay Soil ◽  
Organic Matter Content ◽  
Friction Angle ◽  
Matter Content ◽  
Atterberg Limit ◽  
Shear Characteristics

Most natural sedimentary clay contains organic matter, and even a small amount of organic matter will have a great impact on the physical and mechanical properties of clay. In order to clarify the influence of organic matter content on clay soil, the illite-quartz mixture was mixed with natural amorphous peat soil (organic matter content is 50%) in different proportions for studying the influence of different organic matter contents on the physical properties (specific gravity, Gs; moisture content, w ; void ratio, e; liquid limit, w L ; plastic limit, w p ; plasticity index, Ip) and shear characteristics (cohesion, c; friction angle, φ) of clay soil. The experimental results found that, with the change of organic matter content, the specific gravity and void ratio of clay changed linearly, while the water content, Atterberg limit, shear strength, cohesion, and friction angle changed nonlinearly with the increase of organic matter content. Moisture content and Atterberg limit have a turning point when OC = 7.5%. Shear strength, cohesion, and friction angle all have obvious turning points when OC = 7.5% and OC = 37.5%. The variation of moisture content and Atterberg limit with organic matter content indicates that OC = 7.5% may be the limit value for the different forms of organic matter in the clay. When OC ≤ 7.5%, the organic matter in clay is in the bound state; when OC > 7.5%, the bound organic matter reaches saturation; and the free organic matter gradually increases. The change law of shear strength characteristics with organic matter content shows that the interaction between minerals and organic matter exhibits different shear characteristics under different organic matter content. When OC ≤ 7.5%, clay shows mineral properties, when 7.5% < OC ≤ 37.5%, clay shows mineral-free organic matter properties, and when OC > 37.5%, clay shows free organic matter properties.

scholarly journals Shear Strength Parameters of Cement Stabilized Amorphous Peat of Various Water Additive Ratios at Different Natural Moisture Contents under Consolidated Undrained Triaxial Test

2020 ◽  
Vol 8 (6) ◽  
pp. 317-322
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Triaxial Test ◽  
Peat Soil ◽  
Initial Moisture Content ◽  
Friction Angle ◽  
Moisture Contents ◽  
Shear Characteristic ◽  
Ductile Behavior ◽  
Problematic Soil

Peat is a problematic soil which has a low shear strength characteristic. Addition of cement can improve the properties and strength of peat soil. This paper presents the findings of the shear characteristic of cement stabilized amorphous peat under consolidated undrained (CU) triaxial test. Three different natural moisture contents of peat which are 1210%, 803% and 380%, were stabilized using cement with water to additive (W/A) ratio of 2.0 and 3.0. CU triaxial test was conducted to the specimens after cured for 90 days. The shear parameters and characteristics were investigated towards the change of W/A ratio of the samples with different moisture contents. The result shows that the stabilized peat specimens exhibited ductile behavior and were sensitive to the over consolidation. The total and effective cohesion (ccu, c′) of the stabilized peat were found to be greater at W/A ratio of 2.0 compared to W/A ratio of 3.0, and greater at lower initial moisture content specimens. The total and effective friction angles (φcu, φ′) are ranged from 14o to 27o and 36o to 47o consecutively and found to be increased upon the increase of W/A ratio except for the specimens with moisture content 1210% and 803% in term of total friction angle.

scholarly journals The mechanism of the plant roots’ soil-reinforcement based on generalized equivalent confining pressure

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10064
Author(s):  
Ping Guo ◽  
Zhenyao Xia ◽  
Qi Liu ◽  
Hai Xiao ◽  
Feng Gao ◽  
...  
Keyword(s):  
Shear Strength ◽  
Root Distribution ◽  
Plant Root ◽  
Friction Angle ◽  
Confining Pressure ◽  
Distribution Patterns ◽  
Reinforced Soil ◽  
Soil Reinforcement ◽  
Plant Roots ◽  
Root Content

Background To quantitatively evaluate the contribution of plant roots to soil shear strength, the generalized equivalent confining pressure (GECP), which is the difference in confining pressure between the reinforced and un-reinforced soil specimens at the same shear strength, was proposed and considered in terms of the function of plant roots in soil reinforcement. Methods In this paper, silt loam soil was selected as the test soil, and the roots of Indigofera amblyantha were chosen as the reinforcing material. Different drainage conditions (consolidation drained (CD), consolidation undrained (CU), and unconsolidated undrained (UU)) were used to analyse the influences of different root distribution patterns (horizontal root (HR), vertical root (VR), and complex root (CR)) and root contents (0.25%, 0.50%, and 0.75%) on the shear strength of soil-root composites. Results The cohesion (c) values of the soil-root composites varied under different drainage conditions and root contents, while the internal friction angle (φ ) values remain basically stable under different drainage conditions. Under the same root content and drainage conditions, the shear strength indexes ranked in order of lower to higher were HR, VR and CR. The GECP of the soil-root composites with a 0.75% root content was 1.5–2.0 times that with a 0.50% root content and more than 5 times that with a 0.25% root content under the CD and CU conditions. The GECP in reinforced soil followed the sequence of CD > CU > UU. The GECP of the plant roots increased as confining pressure increased under CD and CU conditions while showed a complex change to the confining pressure under the UU condition. Conclusion It was concluded that the evaluation of plant root reinforcing soil based on GECP can be used to measure effectively the influences of roots on soil under different drainage conditions and root distribution patterns.

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