Through unconfined compressive strength test,influencing factors on compressive strength of solidified inshore saline soil with SH lime-ash,ratio of lime-ash(1-K),quantity of lime-ash,age,degree of compression and sal...Through unconfined compressive strength test,influencing factors on compressive strength of solidified inshore saline soil with SH lime-ash,ratio of lime-ash(1-K),quantity of lime-ash,age,degree of compression and salt content were studied.The results show that because inshore saline soil has special engineering characteristic,more influencing factors must be considered compared with ordinary soil for the perfect effect of solidifying.展开更多
Agricultural liming materials are often applied to the adjustment of soil acidity and the improvement of plant growth and microbial functionality.Relatively low-grade agricultural lime was found to contain up to 125 m...Agricultural liming materials are often applied to the adjustment of soil acidity and the improvement of plant growth and microbial functionality.Relatively low-grade agricultural lime was found to contain up to 125 mg/kg arsenic(As),which is above any fertilizing materials’ toxicity threshold limit.Several techniques were employed to determine the speciation of the arsenic.Results from microprobe analyses suggest that minor minerals such as black and brown dendrites are the source of high arsenic concentrations in the samples.X-ray fluorescence spectroscopy provided further information that ferrihydrite and crystalline goethite are responsible for hosting the high concentration of arsenic with Fe/As molar ratio in around 100.A five-step sequential extraction demon-展开更多
Many construction and post-construction problems have been reported in the literature when saline soils have been used without understanding of their abnormal behavior,especially their inferior bearing capacity in the...Many construction and post-construction problems have been reported in the literature when saline soils have been used without understanding of their abnormal behavior,especially their inferior bearing capacity in the natural condition.The strength of these soils further decreases on soaking.Saline soil deposits cover extensive areas in central Iran and are associated with geotechnical problems such as excessive differential settlement,susceptibility to strength loss and collapse upon wetting.Because of these characteristics,some of the roads constructed on saline soils in Taleghan area have exhibited deterioration in the form of raveling,cracking and landslides.The main objective of this work is to improve the load-bearing capacity of pavements constructed on Taleghan saline soils using lime and micro silica.Soil samples from Hashtgerd-Taleghan road were collected and tested for improving their properties using lime and micro silica at different dosages ranging from 0 to 6%.The load-bearing capacity of stabilized soil mixtures was evaluated using California Bearing Ratio(CBR) and unconfined compressive strength tests.The test results indicate that the lime improves the performance of soil significantly.The addition of 2% lime with 3% micro silica has satisfied the strength-deformation requirements.Therefore,improved soil can be used as a good subbase in flexible pavements.展开更多
Through laboratory test, the relationships among change of compactibility, liquid/plastic limit, free swell, swell ratio without load, california bearing ratio (CBR) and soakage (after being soaked in water), and mix-...Through laboratory test, the relationships among change of compactibility, liquid/plastic limit, free swell, swell ratio without load, california bearing ratio (CBR) and soakage (after being soaked in water), and mix-ratio of quick lime and time were studied. The results show that optimum water content, plastic limit and CBR of high liquid limit clay improved by quick lime increase with the increase of mix-ratio of quick lime, while the maximum dry density, liquid limit, plasticity index, soakage (after being immersed in water), free swell, and swell ratio without load decrease with the increase of mix-ratio of quick lime. Plastic limit of high liquid clay improved by quick lime gradually increases with time, while the liquid limit, plasticity index, free swell and swell ratio without load gradually decrease with time. When the mix-ratio of quick lime exceeds 2%, after 14 d, swell ratio without load of the improved clay is zero, its free swell is about 30% of that of untreated soil, and its plasticity index is less than 26 for sub-grade material, satisfying the requirement by 'Specifications for Design of Highway Subgrade'.展开更多
Based on the principle of thermal balance and material balance of lime furnace, the reaction and heat transfer process mathematical-physical model and the on-line monitoring model of the decomposition rate of limeston...Based on the principle of thermal balance and material balance of lime furnace, the reaction and heat transfer process mathematical-physical model and the on-line monitoring model of the decomposition rate of limestone were set up. With this model, numerical simulation is used to analyze the effects of operational parameters on the process of lime calcining and to optimize it. By using visual basic program to communicate and program, the centralized management and automatic control of the lime furnace are realized. The software is put into practical production, which makes the lime furnace operate steadily and efficiently, and causes the increase in output and decrease in energy consumption.展开更多
Heap leaching is a promising, less costly, alternative technology for processing low grade gold ores compared with traditional, energy intensive processes (e.g. autoclave/tank leaching). This research investigated the...Heap leaching is a promising, less costly, alternative technology for processing low grade gold ores compared with traditional, energy intensive processes (e.g. autoclave/tank leaching). This research investigated the effectiveness of lime for enhancing gold leaching rates of gold ores from ajialongwa gold mine in china. Column and heaping experiments were performed using cyanide leaching solutions at pH=10, with and without lime (CaO). The presence of lime greatly increased gold leaching rates. Column leaching experiments showed without the addition of lime, there was 35.2% of gold leached. The addition of lime resulted in the release of 50.56% gold. Lime assisted cyanide of refractory gold was proved by heap leaching experiments.展开更多
The past decade has been characterized by the development of infrastructure in the main cities in West Africa.This requires more comprehensive studies of geotechnical properties of the soil in the region with an aim o...The past decade has been characterized by the development of infrastructure in the main cities in West Africa.This requires more comprehensive studies of geotechnical properties of the soil in the region with an aim of creating sustainable development.This paper examined the performance of the soil in Benin(West Africa).In this research,three objectives have been adopted in-depth on the performance characteristics of West Africans soil and aim to(i)accessing characteristics of soil types in the region;(ii)assessing the performance of these soils with 2%,3%and 5%of lime and(iii)characterizing landslide to evaluate the damage and potential instability.The methods used to examine these objectives are experimental tests according to standard French test.The particle size test,Proctor test,and Atterberg limits test which are physical tests and the mechanical tests such as dynamic penetration test,direct shear test,and oedometer test,were used to assess the first objective.The Proctor test and California bearing ratio test were examined for the second objective and geological,environmental,social and safety study of the river bank slide were evaluated for the third objective.This paper firstly reveals the unstable and stable areas in southern Benin(West Africa)with the presence of clays soil and gives an equation for predicting the unstable and stable area,and secondly shows that the proportion of percentage lime leading to the best performances varying between 2%and 3%.Finally,this paper shows that the sliding of a bank could be the consequence of the sudden receding water recorded in a valley.展开更多
红层泥岩水敏性高,作路基填料时可用石灰改良。受季节变化影响,路基基床经历干湿循环,导致服役性能降低。为研究干湿循环下改良填料力学特性劣化规律,开展一系列干湿循环试验、无侧限抗压试验和弯曲元试验测定改良填料无侧限抗压强度和...红层泥岩水敏性高,作路基填料时可用石灰改良。受季节变化影响,路基基床经历干湿循环,导致服役性能降低。为研究干湿循环下改良填料力学特性劣化规律,开展一系列干湿循环试验、无侧限抗压试验和弯曲元试验测定改良填料无侧限抗压强度和小应变刚度。结合连续滴水扫描电镜(scanning electron microscope,简称SEM)试验,揭示干湿循环后填料微观结构劣化特征。结果表明:低幅度循环下试样在干侧和湿侧均产生体胀。高幅度循环下试样在湿侧产生体胀。在干侧先产生体缩,随循环次数增加,即使含水率较低,试样也产生体胀。体胀导致强度和小应变刚度均有不同程度的劣化。当试样产生体缩时,强度有所增长,但小应变刚度由于裂缝衍生而持续衰减。试样强度随损伤体变可用统一劣化方程表示。但高幅度循环下试样干燥后的小应变刚度远低于劣化线,且劣化速率远大于强度。试样滴水后能维持基本形貌,但观察到团聚体松散、微粒剥落和新生裂缝等结构劣化特征,从而导致宏观力学性能衰减。展开更多
基金Project(05YFSYSF00300) supported by the Natural Science Foundation of Tianjin
文摘Through unconfined compressive strength test,influencing factors on compressive strength of solidified inshore saline soil with SH lime-ash,ratio of lime-ash(1-K),quantity of lime-ash,age,degree of compression and salt content were studied.The results show that because inshore saline soil has special engineering characteristic,more influencing factors must be considered compared with ordinary soil for the perfect effect of solidifying.
文摘Agricultural liming materials are often applied to the adjustment of soil acidity and the improvement of plant growth and microbial functionality.Relatively low-grade agricultural lime was found to contain up to 125 mg/kg arsenic(As),which is above any fertilizing materials’ toxicity threshold limit.Several techniques were employed to determine the speciation of the arsenic.Results from microprobe analyses suggest that minor minerals such as black and brown dendrites are the source of high arsenic concentrations in the samples.X-ray fluorescence spectroscopy provided further information that ferrihydrite and crystalline goethite are responsible for hosting the high concentration of arsenic with Fe/As molar ratio in around 100.A five-step sequential extraction demon-
文摘Many construction and post-construction problems have been reported in the literature when saline soils have been used without understanding of their abnormal behavior,especially their inferior bearing capacity in the natural condition.The strength of these soils further decreases on soaking.Saline soil deposits cover extensive areas in central Iran and are associated with geotechnical problems such as excessive differential settlement,susceptibility to strength loss and collapse upon wetting.Because of these characteristics,some of the roads constructed on saline soils in Taleghan area have exhibited deterioration in the form of raveling,cracking and landslides.The main objective of this work is to improve the load-bearing capacity of pavements constructed on Taleghan saline soils using lime and micro silica.Soil samples from Hashtgerd-Taleghan road were collected and tested for improving their properties using lime and micro silica at different dosages ranging from 0 to 6%.The load-bearing capacity of stabilized soil mixtures was evaluated using California Bearing Ratio(CBR) and unconfined compressive strength tests.The test results indicate that the lime improves the performance of soil significantly.The addition of 2% lime with 3% micro silica has satisfied the strength-deformation requirements.Therefore,improved soil can be used as a good subbase in flexible pavements.
文摘Through laboratory test, the relationships among change of compactibility, liquid/plastic limit, free swell, swell ratio without load, california bearing ratio (CBR) and soakage (after being soaked in water), and mix-ratio of quick lime and time were studied. The results show that optimum water content, plastic limit and CBR of high liquid limit clay improved by quick lime increase with the increase of mix-ratio of quick lime, while the maximum dry density, liquid limit, plasticity index, soakage (after being immersed in water), free swell, and swell ratio without load decrease with the increase of mix-ratio of quick lime. Plastic limit of high liquid clay improved by quick lime gradually increases with time, while the liquid limit, plasticity index, free swell and swell ratio without load gradually decrease with time. When the mix-ratio of quick lime exceeds 2%, after 14 d, swell ratio without load of the improved clay is zero, its free swell is about 30% of that of untreated soil, and its plasticity index is less than 26 for sub-grade material, satisfying the requirement by 'Specifications for Design of Highway Subgrade'.
文摘Based on the principle of thermal balance and material balance of lime furnace, the reaction and heat transfer process mathematical-physical model and the on-line monitoring model of the decomposition rate of limestone were set up. With this model, numerical simulation is used to analyze the effects of operational parameters on the process of lime calcining and to optimize it. By using visual basic program to communicate and program, the centralized management and automatic control of the lime furnace are realized. The software is put into practical production, which makes the lime furnace operate steadily and efficiently, and causes the increase in output and decrease in energy consumption.
文摘Heap leaching is a promising, less costly, alternative technology for processing low grade gold ores compared with traditional, energy intensive processes (e.g. autoclave/tank leaching). This research investigated the effectiveness of lime for enhancing gold leaching rates of gold ores from ajialongwa gold mine in china. Column and heaping experiments were performed using cyanide leaching solutions at pH=10, with and without lime (CaO). The presence of lime greatly increased gold leaching rates. Column leaching experiments showed without the addition of lime, there was 35.2% of gold leached. The addition of lime resulted in the release of 50.56% gold. Lime assisted cyanide of refractory gold was proved by heap leaching experiments.
基金Project(41627801)supported by the National Major Scientific Instruments Development Project of ChinaProject(41430634)supported by the State Key Program of National Natural Science Foundation of China+1 种基金Project(2016YJ004)supported by the Opening Fund for Innovation Platform of ChinaProject(2016G002-F)supported by the Technology Research and Development Plan Program of China Railway Corporation
文摘The past decade has been characterized by the development of infrastructure in the main cities in West Africa.This requires more comprehensive studies of geotechnical properties of the soil in the region with an aim of creating sustainable development.This paper examined the performance of the soil in Benin(West Africa).In this research,three objectives have been adopted in-depth on the performance characteristics of West Africans soil and aim to(i)accessing characteristics of soil types in the region;(ii)assessing the performance of these soils with 2%,3%and 5%of lime and(iii)characterizing landslide to evaluate the damage and potential instability.The methods used to examine these objectives are experimental tests according to standard French test.The particle size test,Proctor test,and Atterberg limits test which are physical tests and the mechanical tests such as dynamic penetration test,direct shear test,and oedometer test,were used to assess the first objective.The Proctor test and California bearing ratio test were examined for the second objective and geological,environmental,social and safety study of the river bank slide were evaluated for the third objective.This paper firstly reveals the unstable and stable areas in southern Benin(West Africa)with the presence of clays soil and gives an equation for predicting the unstable and stable area,and secondly shows that the proportion of percentage lime leading to the best performances varying between 2%and 3%.Finally,this paper shows that the sliding of a bank could be the consequence of the sudden receding water recorded in a valley.
文摘红层泥岩水敏性高,作路基填料时可用石灰改良。受季节变化影响,路基基床经历干湿循环,导致服役性能降低。为研究干湿循环下改良填料力学特性劣化规律,开展一系列干湿循环试验、无侧限抗压试验和弯曲元试验测定改良填料无侧限抗压强度和小应变刚度。结合连续滴水扫描电镜(scanning electron microscope,简称SEM)试验,揭示干湿循环后填料微观结构劣化特征。结果表明:低幅度循环下试样在干侧和湿侧均产生体胀。高幅度循环下试样在湿侧产生体胀。在干侧先产生体缩,随循环次数增加,即使含水率较低,试样也产生体胀。体胀导致强度和小应变刚度均有不同程度的劣化。当试样产生体缩时,强度有所增长,但小应变刚度由于裂缝衍生而持续衰减。试样强度随损伤体变可用统一劣化方程表示。但高幅度循环下试样干燥后的小应变刚度远低于劣化线,且劣化速率远大于强度。试样滴水后能维持基本形貌,但观察到团聚体松散、微粒剥落和新生裂缝等结构劣化特征,从而导致宏观力学性能衰减。
