The Experts below are selected from a list of 4542 Experts worldwide ranked by ideXlab platform
Kelda Rankine - One of the best experts on this subject based on the ideXlab platform.
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drainage behaviour of three dimensional Hydraulic fill stopes a sensitivity analysis
2007Co-Authors: Siva Sivakugan, Kelda RankineAbstract:Recent barricade failures in underground Hydraulic fill mines in Australia and overseas, have resulted in significant economic loss and on a number of occasions, loss of lives. As a result, there is an urgent need in the mining industry for proper understanding of underground Filling practices and in particular the use of Hydraulic Filling. Using analytical solutions developed for flow through three-dimensional Hydraulic fill stopes, an EXCEL model was developed 'to accurately and efficiently model the drainage behaviour in three-dimensional stopes. The model simulates the complete Filling and draining of the stopes and was verified using the three-dimensional finite difference program and results showed excellent agreement. This paper investigates the variation and sensitivity in drainage behaviour and pore water pressure measurements with, the fill properties of a three-dimensional Hydraulic fill stope. The model studied in this paper assumes a simple drain geometry, with a square based stope and single square drain outlet located at the centre of the stope face.
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a simple solution for drainage through a 2 dimensional Hydraulic fill stope
Geotechnical and Geological Engineering, 2006Co-Authors: Nagaratnam Sivakugan, Kelda RankineAbstract:Inadequate drainage has been attributed as the major cause of failure of several Hydraulic fill stopes that have claimed lives. Therefore it is necessary to be able to predict the pore water pressure developments and flow rates throughout the Filling operation. There are computer programmes that can simulate the Hydraulic Filling of a mine stope and enable computations of the pore water pressures, flow rates and Hydraulic gradients at any time. This paper presents a simple analytical solution for estimating the maximum pore water pressure within the stope, flow rate and the Hydraulic gradients at the entry and exit. The proposed solutions are verified against solutions derived from FLAC, a finite difference software, and the agreement is found to be excellent. A simple equation for the Hydraulic gradient at the top of the stope, as a function of the height of water within the fill, is also presented.
Qiong Wang - One of the best experts on this subject based on the ideXlab platform.
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sand fraction effect on hydro mechanical behavior of sand clay mixture
Applied Clay Science, 2017Co-Authors: Yongfeng Deng, Yujun Cui, Songyu Liu, Qiong WangAbstract:Abstract The sand-clay mixture was prepared to simulate special soils with discontinuous gradations, e . g . the residual soils, clinosols or Hydraulic Filling soils. Incremental loading oedometer tests were conducted to investigate their hydro-mechanical behaviors. The results were first analyzed based on the plots in the semi-logarithmic planes ( i . e . normalized void ratio by that at liquid limit versus vertical effective stress, and ver sus Hydraulic conductivity). It appears that the normalized void ratio by that at liquid limit allows valuable and reliable normalization of the compressibility and permeability curves. To investigate the influence of sand fraction, a four-phase model of sand-clay mixture was introduced, enabling the void ratios of clay and sand to be determined. Further analysis showed that the sand void ratio and the normalized clay void ratio by that at liquid limit are also suitable parameters to describe the sand skeleton formation. Moreover, the normalized clay void ratio by that at liquid limit is an appropriate parameter to describe the Hydraulic behavior of soils with or without sand fraction. When the sand skeleton was partly formed, the vertical stress was partly supported by the skeleton resulting in a different compression behavior from that of common clays. The partial formation of skeleton was found to depend on the relative dimension of coarse to fine grains as well as the stress state. This implies that during compression the interaction between sand and clay evolves, from non-, partial- to complete sand skeleton, reaching at the end of the maximum void ratio of sand.
Nagaratnam Sivakugan - One of the best experts on this subject based on the ideXlab platform.
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a simple solution for drainage through a 2 dimensional Hydraulic fill stope
Geotechnical and Geological Engineering, 2006Co-Authors: Nagaratnam Sivakugan, Kelda RankineAbstract:Inadequate drainage has been attributed as the major cause of failure of several Hydraulic fill stopes that have claimed lives. Therefore it is necessary to be able to predict the pore water pressure developments and flow rates throughout the Filling operation. There are computer programmes that can simulate the Hydraulic Filling of a mine stope and enable computations of the pore water pressures, flow rates and Hydraulic gradients at any time. This paper presents a simple analytical solution for estimating the maximum pore water pressure within the stope, flow rate and the Hydraulic gradients at the entry and exit. The proposed solutions are verified against solutions derived from FLAC, a finite difference software, and the agreement is found to be excellent. A simple equation for the Hydraulic gradient at the top of the stope, as a function of the height of water within the fill, is also presented.
Yongfeng Deng - One of the best experts on this subject based on the ideXlab platform.
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sand fraction effect on hydro mechanical behavior of sand clay mixture
Applied Clay Science, 2017Co-Authors: Yongfeng Deng, Yujun Cui, Songyu Liu, Qiong WangAbstract:Abstract The sand-clay mixture was prepared to simulate special soils with discontinuous gradations, e . g . the residual soils, clinosols or Hydraulic Filling soils. Incremental loading oedometer tests were conducted to investigate their hydro-mechanical behaviors. The results were first analyzed based on the plots in the semi-logarithmic planes ( i . e . normalized void ratio by that at liquid limit versus vertical effective stress, and ver sus Hydraulic conductivity). It appears that the normalized void ratio by that at liquid limit allows valuable and reliable normalization of the compressibility and permeability curves. To investigate the influence of sand fraction, a four-phase model of sand-clay mixture was introduced, enabling the void ratios of clay and sand to be determined. Further analysis showed that the sand void ratio and the normalized clay void ratio by that at liquid limit are also suitable parameters to describe the sand skeleton formation. Moreover, the normalized clay void ratio by that at liquid limit is an appropriate parameter to describe the Hydraulic behavior of soils with or without sand fraction. When the sand skeleton was partly formed, the vertical stress was partly supported by the skeleton resulting in a different compression behavior from that of common clays. The partial formation of skeleton was found to depend on the relative dimension of coarse to fine grains as well as the stress state. This implies that during compression the interaction between sand and clay evolves, from non-, partial- to complete sand skeleton, reaching at the end of the maximum void ratio of sand.
Qi Feng - One of the best experts on this subject based on the ideXlab platform.
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Colloid effect on clogging mechanism of Hydraulic reclamation mud improved by vacuum preloading
'Canadian Science Publishing', 2019Co-Authors: Deng Yongfeng, Li Liu, Cui Yu-jun, Qi Feng, Chen Xianglong, He NingAbstract:International audienceMany cases of artificial soft clay foundation constructed by Hydraulic Filling and improved by the vacuum preloading show the clogging phenomenon in the surrounding soil, which compromises the improvement quality. To clarify the clogging mechanism and the formation of soil columns, the vacuum process was tracked from macro to micro by laboratory model tests. Results show that the soil column with higher strength (density) and lower water content was formed surrounding the prefabricated vertical drainage (PVD). Mercury intrusion porosimetry (MIP) tests revealed that the pore-entrance diameter of the soil column after 50 and 43 days of vacuum application ranged from 100 to 600 nm, and that at peak it is 300 nm. However, the mean diameter of the colloidal particles in tail water decreases from 1000 to 100 nm with continuous vacuum application, and then becomes stable at about 100 nm after 43 days. After re-visiting the vacuum process of the Hydraulic reclamation mud, the pore-size distribution of surrounding soils and particle-size distribution of the tail water, the clogging was explained by the Filling of the pores of the soil column by the colloidal particles in pore water. This mechanism differentiates the artificialDe nombreux cas de fondations en argile molle artificielle construites par remplissage hydraulique et améliorées par la précharge sous vide montrent le phénomène de colmatage dans le sol environnant, qui compromet la qualité de l’amélioration. Pour clarifier le mécanisme de colmatage et la formation des colonnes de sol, le processus de vide a été suivi de macro à micro par des tests de modèle de laboratoire. Les résultats montrent que la colonne de sol avec une plus grande résistance (densité) et une plus faible teneur en eau a été formée autour du drainage vertical préfabriqué (« PVD »). Les tests de porosimétrie au mercure (« MIP ») ont révélé que le diamètre d’entrée des pores de la colonne de sol après 50 et 43 jours de vide variait de 100 à 600 nm et que le pic atteignait 300 nm. Cependant, le diamètre moyen des particules colloïdales dans l’eau d’aval diminue de 1000 à 100 nm avec une application continue sous vide, puis devient stable à environ 100 nm après 43 jours. Après avoir revu le processus de vide de la boue de récupération hydraulique, la distribution de la taille des pores des sols environnants et la distribution granulométrique de l’eau d’aval, le colmatage a été expliqué par le remplissage des pores de la colonne de sol par les particules colloïdales dans l’eau interstitielle. Ce mécanisme différencie la fondation artificielle améliorée par le préchargement sous vide de la fondation naturelle pour la présence de particules colloïdales riches dans l’eau interstitielle
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Investigations on secondary compression behaviours of artificial soft sand-clay mixtures
'Elsevier BV', 2019Co-Authors: Wu Zilong, Deng Yongfeng, Cui Yu-jun, Chen Yonggui, Wang Qiong, Qi FengAbstract:International audienceSpecial soft soils with notable coarse and fine fractions are not only naturally deposited in ravines or interactive marine-terrestrial sedimentation areas but also artificially formed in land reclamation projects via the Hydraulic Filling method and excavation cuts of different soil layers in open pit mines. The behaviour of these soils is not like that of similar normal sands or clays but rather exhibits the characteristics of transitional mixtures. A sand-clay mixture was prepared in the laboratory to simulate these special soil types, and an incremental loading oedometer test was performed. Thereafter, a secondary compression coefficient (Cα) was determined to investigate the long-term rheological properties of the mixture. The results in the Cα-log σv′, Cα-e, Cα-e/eL and Cα-Cc planes revealed that a threshold e/eL value (i.e. approximately 0.45) in the case of sands. Note that in a traditional Cα-Cc analysis system, the soils with sand exhibited the same secondary compression behaviour (SCB) as that without sand before reaching the transformation threshold, whereas after this threshold, they appeared to behave much like sandy soils. Hence, a four-phase frame of sand-clay mixture was further introduced to clarify the mechanism of the SCB of soils with and without sand. An updated Cαc/Ccc reflecting the creep mechanism of the clay phase can be effectively adopted to exclude the influence of sand particles. Because the quantitative relationship between Cαc and Ccc for soils with sand was consistent with that without sand, it can be assumed that the SCB of clay-sand mixtures was dominated by the creep of fine fractions. It is porposed that the existence pattern of the sand particles in the mixtures undergoes three stages with an increasing vertical stress, i.e. non-skeleton, partial skeleton and complete skeleton. A further discussion on the mutual relationship between phases on the behaviour of mixtures with sand revealed that isolated sand had no effect on the compressibility and SCB during the initial stage. When a partial skeleton of the sand was established in the second stage, characterized by less stress on the clay matrix, the compressibility and SCB were suppressed. When the vertical stress continuously increased or additional sand content was supplied, a complete skeleton formed. Hence, the behaviour of mixtures (regardless of compressibility and secondary compression) was completely governed by the sand fractions. Generally, the same relationship was observed between Cαc and Ccc during the first and second stages with sand, indicating that the influence of sand fractions on the compressibility and SCB can be counterweighted
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Colloid effect on Clogging Mechanism of Hydraulic reclamation mud improved by vacuum preloading
NRC Research Press (a division of Canadian Science Publishing), 2018Co-Authors: Deng Yongfeng, Li Liu, Cui Yu-jun, Qi Feng, Chen Xianglong, He NingAbstract:Many cases of artificial soft clay foundation constructed by Hydraulic Filling and improved by the vacuum preloading show the clogging phenomenon in the surrounding soil, which compromise the improvement quality. To clarify the clogging mechanism and the formation of soil columns, the vacuum process was tracked from macro to micro by laboratory model tests. Results show that the soil column was formed surrounding PVD with higher strength (density) and lower water content. MIP (Mercury intrusion porosimetry) tests revealed that the pore-entrance diameter of the soil column after 50 and 43 daysâ vacuum ranged from 100 to 600 nm, and that at peak is 300 nm. However, the mean diameter of the colloidal particles in tail water decreases from 1000 to 100 nm with continuous vacuum application, and then becomes stable at about 100 nm after 43 day. After re-visiting the vacuum process of the Hydraulic reclamation mud, the pore size distribution of surrounding soils and particle size distribution of the tail water, the clogging was explained by the Filling of the pores of soil column by the colloidal particles in pore water. This mechanism differentiates the artificial foundation improved by vacuum preloading from the natural foundation for the presence of rich colloidal particles in pore water.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
