scholarly journals Study on Mechanical Characteristics of Composite Alkali-activated Materials-stabilized Gold Tailings Under Direct Shear

2021 ◽  
Author(s):  
Zhenkai Pan ◽  
Chao Zhang ◽  
Yuan Li ◽  
Shucheng Gan
Keyword(s):  
Shear Strength ◽  
Mine Tailings ◽  
Mechanical Characteristics ◽  
Confining Pressure ◽  
Gold Mine ◽  
Direct Shear ◽  
Type Curves ◽  
Direct Shear Tests ◽  
Gold Mine Tailings ◽  
Alkali Activated

Abstract In this study, the traditional industrial waste residue and some alkaline activators were mixed to prepare a new composite alkali-activated materials (CAAMs), which was used to stabilize gold mine tailings (GMTs). Due to emissions of greenhouse gases and solid dust, alkali-activated materials have been widely used to replace Portland cement to solidify geotechnical materials to enhance their mechanical properties. Different admixture of CAAMs (i.e., 0, 3, 5, 8% ) and gold mine tailings were prepared, and the samples were cured in saturated water and under no air conditions. In order to investigate the mechanical characteristics of CAAMs-stabilized GMTs, laboratory direct shear tests were carried out on samples after curing them for 3, 7, 14 and 28 days, respectively. The test results showed that as the curing periods increased, the brittleness of the samples increased, and the stress-displacement curves for all the cured specimens changed from plateau-type to peak-type curves. The curing periods and the content of CAAMs are both beneficial for enhancing the shear strength of CAAMs-stabilized GMTs samples, but the increase rate decreased as the vertical confining pressure increased. Furthermore, the influence of CAAMs content on shear strength increment was larger than that of curing periods. An exponential growth model could be well used to describe the change of shear strength with the curing periods at different vertical stresses.

Effect of fibre content and structure on anisotropic elastic stiffness and shear strength of peat

2012 ◽  
Vol 49 (4) ◽  
pp. 403-415 ◽  
Author(s):  
Michael T. Hendry ◽  
Jitendra S. Sharma ◽  
C. Derek Martin ◽  
S. Lee Barbour
Keyword(s):  
Shear Strength ◽  
Confining Pressure ◽  
Deviatoric Stress ◽  
Direct Shear ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
A Value ◽  
Frictional Strength ◽  
Fibrous Peat ◽  
Interparticle Friction

This paper presents the results of a laboratory testing program involving consolidated undrained triaxial tests and direct shear tests on remoulded peat, remoulded peat fibre, and Shelby specimens of peat obtained from a field site located in the Edson subdivision of the Canadian National railway in Alberta, Canada. These results were analyzed within the frameworks of elastic behaviour of cross-anisotropic materials and shear strength of fibre-reinforced soil. Shelby specimens were found to be inherently cross-anisotropic, whereas the remoulded peat and peat fibre specimens showed a transition from isotropic to cross-anisotropic with increasing vertical strain and effective confining pressure. The horizontal stiffness of Shelby specimens was found to be 2.6 to 2.9 times their vertical stiffness. The shear strength of intact peat is made up of interparticle friction as well as tension in the peat fibres. A novel procedure for estimating the interparticle frictional strength of fibrous peat from CU triaxial test results is proposed. It involves extrapolating the linear strain-hardening portion of the stress–strain curve to obtain the deviatoric stress at zero axial strain and plotting the deviatoric stress values thus obtained against initial mean effective confining pressure to obtain the frictional strength. Using this procedure, a value of 31° was obtained for the interparticle friction, which compares favourably with a value of 31° obtained from direct shear tests. It is recommended that further studies be undertaken to assess if interparticle frictional strength is an appropriate strength parameter for evaluation of the stability of structures founded on fibrous peat.

scholarly journals Mechanical Properties and Micro Mechanism of Nano-Clay-Modified Soil Cement Reinforced by Recycled Sand

2021 ◽  
Vol 13 (14) ◽  
pp. 7758
Author(s):  
Biao Qian ◽  
Wenjie Yu ◽  
Beifeng Lv ◽  
Haibo Kang ◽  
Longxin Shu ◽  
...  
Keyword(s):  
Shear Strength ◽  
Void Ratio ◽  
Soil Mass ◽  
Direct Shear ◽  
Test Results ◽  
The Sustainable Development ◽  
Direct Shear Tests ◽  
Soil Cement ◽  
Nano Clay ◽  
New Material

To observe the effect of recycled sand and nano-clay on the improvement of the early strength of soil-cement (7d), 0%, 10%, 15% and 20% recycled sand were added. While maintaining a fixed moisture content of 30%, the ratios of each material are specified in terms of soil mass percentage. The shear strength of CSR (recycled sand blended soil-cement) was investigated by direct shear test and four groups of specimens (CSR-1, CSR-2, CSR-3 and CSR-4) were obtained. In addition, 8% nano-clay was added to four CSR groups to obtain the four groups of CSRN-1, CSRN-2, CSRN-3 and CSRN-4 (soil-cement mixed with recycled sand and nano-clay), which were also subjected to direct shear tests. A detailed analysis of the modification mechanism of soil-cement by recycled sand and nano-clay was carried out in combination with scanning electron microscopy (SEM) and IPP (ImagePro-Plus) software. The test results showed that: (1) CSR-3 has the highest shear strength due to the “concrete-like” effect of the incorporation of recycled sand. With the addition of 8% nano-clay, the overall shear strength of the cement was improved, with CSRN-2 having the best shear strength, thanks to the filling effect of the nano-clay and its high volcanic ash content. (2) When recycled sand and nano-clay were added to soil-cement, the improvement in shear strength was manifested in a more reasonable macroscopic internal structure distribution of soil-cement. (3) SEM test results showed that the shear strength was negatively correlated with the void ratio of its microstructure. The smaller the void ratio, the greater the shear strength. This shows that the use of reclaimed sand can improve the sustainable development of the environment, and at the same time, the new material of nano-clay has potential application value.

scholarly journals Potential utilization of artisanal gold-mine tailings as geopolymeric source material: preliminary investigation

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
John Paul J. Aseniero ◽  
Einstine M. Opiso ◽  
Marybeth Hope T. Banda ◽  
Carlito B. Tabelin
Keyword(s):  
Mine Tailings ◽  
Preliminary Investigation ◽  
Source Material ◽  
Gold Mine ◽  
Gold Mine Tailings

scholarly journals Strength Tests and Numerical Simulations of Loess Modified by Desulfurization Ash and Fly Ash

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 512
Author(s):  
Zhi Cheng ◽  
Xinrong Cheng ◽  
Yuchao Xie ◽  
Zhe Ma ◽  
Yuhao Liu
Keyword(s):  
Shear Strength ◽  
Fly Ash ◽  
Power Plants ◽  
Utilization Rate ◽  
Direct Shear ◽  
Test Results ◽  
Mass Ratio ◽  
Direct Shear Tests ◽  
Strength Tests ◽  
Actual Test

Desulfurization ash and fly ash are solid wastes discharged from boilers of power plants. Their utilization rate is low, especially desulfurization ash, most of which is stored. In order to realize their resource utilization, they are used to modify loess in this paper. Nine group compaction tests and 32 group direct shear tests are done in order to explore the influence law of desulfurization ash and fly ash on the strength of the loess. Meanwhile, FLAC3D software is used to numerically simulate the direct shear test, and the simulation results and the test results are compared and analyzed. The results show that, with the increase of desulfurization ash’s amount, the shear strength of the modified loess increases first and then decreases. The loess modified by the fly ash has the same law with that of the desulfurization ash. The best mass ratio of modified loess is 80:20. When the mass ratio is 80:20, the shear strength of loess modified by the desulfurization ash is 12.74% higher than that of the pure loess on average and the shear strength of loess modified by fly ash is 3.59% higher than that of the pure loess on average. The effect of the desulfurization ash on modifying the loess is better than that of the fly ash. When the mass ratio is 80:20, the shear strength of loess modified by the desulfurization ash is 9.15% higher than that of the fly ash on average. Comparing the results of the simulation calculation with the actual test results, the increase rate of the shear stress of the FLAC3D simulation is larger than that of the actual test, and the simulated shear strength is about 8.21% higher than the test shear strength.

scholarly journals Growth, histochemical and physiological responses of non-edible oil producing plant (Reutealis trisperma) to gold mine tailings

2018 ◽  
Vol 19 (4) ◽  
pp. 1294-1302 ◽  
Author(s):  
MUHAMMAD HILMI ◽  
HAMIM HAMIM ◽  
YOHANA C. SULISTYANINGSIH ◽  
TAUFIKURAHMAN TAUFIKURAHMAN
Keyword(s):  
Mine Tailings ◽  
Shoot Growth ◽  
Physiological Responses ◽  
Gold Mine ◽  
Histochemical Analysis ◽  
Root And Shoot Growth ◽  
Gold Mine Tailings ◽  
Chlorophyll A And B ◽  
Anatomical Characters ◽  
High Level

Hilmi M, Hamim H, Sulistyaningsih YC, Taufikurahman. 2018. Growth, histochemical and physiological responses of nonedibleoil producing plant (Reutealis trisperma) to gold mine tailings. Biodiversitas 19: 1294-1302. Reutealis trisperma (Blanco) AiryShaw is a non-edible biodiesel producing plant that is able to grow well in various unfavorable environmental conditions. The studyaimed to analyze the growth, physiological, and anatomical responses of R. trisperma to gold mine tailings. Three-month-old of R.trisperma were grown in 8 kg of polybags contained with mixed soil-compost medium treated with 0, 25, 50 and 100% of gold minetailings for 3 months. Root and shoot growth, physiological and anatomical characters, and histochemical analysis of Pb inside the rootsand leaves were examined. The root and shoot growth as well as chlorophyll a and b contents of R. trisperma grown in sole gold minetailing at 100% significantly decreased, while at the lower concentration of gold mine tailings, the decrease of the growth performanceswas not significant, or even increased shown in that of 25% of tailing treatment. The treatment of gold mine tailing at 100% alsoinduced lipid peroxidation, indicated by the significant increase in malondialdehyde (MDA) contents in the root as well as the leaves.Histochemical analysis showed that accumulation of Pb occurred both in roots as well as in leaves of R. trisperma treated with 100% oftailings. High-level tailing treatment also induced anatomical alteration in roots as well as leaves of the species. These results indicatedthat gold mine tailings induced oxidative stress in roots and leaves of R. trisperma resulted in growth inhibition.

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