The Experts below are selected from a list of 2484 Experts worldwide ranked by ideXlab platform
Gopal S. P. Madabhushi - One of the best experts on this subject based on the ideXlab platform.
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Seismic behaviour of soft clay and its influence on the response of friction pile foundations
Bulletin of Earthquake Engineering, 2019Co-Authors: Thejesh Kumar Garala, Gopal S. P. MadabhushiAbstract:In recent years, much of the research in geotechnical earthquake engineering has focused on liquefaction of loose, saturated sands and silts. However, the dynamic behaviour of soft, clayey soils and their interaction with pile foundations during the earthquakes have received relatively little attention. In this study, an attempt is made to investigate the dynamic behaviour of soft clay and its interaction with pile foundations during earthquakes using high gravity centrifuge testing. A model single pile and two sets of 3 × 1 row model pile groups with different pile spacing were embedded in soft kaolin clay and tested under the action of model earthquakes at 50 times the earth’s gravity. The strength and stiffness of clay were evaluated using a T-bar test and an Air Hammer device respectively. The focus of this research is to investigate the dynamic response of friction piles in soft clay. However, this depends on the dynamic response of the soft clay layer around the pile. To this end, one-dimensional ground response analysis was performed using DEEPSOIL software to emphasise the importance of non-linear analysis in characterising the seismic behaviour of soft clays. It will be shown that clay response depends both on the earthquake intensity and the shear strength and stiffness of the clay layer. This has a direct bearing on the response of single piles and pile groups, with larger amplification occurring for small intensity earthquakes and attenuation occurring for stronger earthquakes.
Thejesh Kumar Garala - One of the best experts on this subject based on the ideXlab platform.
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Seismic behaviour of soft clay and its influence on the response of friction pile foundations
Bulletin of Earthquake Engineering, 2019Co-Authors: Thejesh Kumar Garala, Gopal S. P. MadabhushiAbstract:In recent years, much of the research in geotechnical earthquake engineering has focused on liquefaction of loose, saturated sands and silts. However, the dynamic behaviour of soft, clayey soils and their interaction with pile foundations during the earthquakes have received relatively little attention. In this study, an attempt is made to investigate the dynamic behaviour of soft clay and its interaction with pile foundations during earthquakes using high gravity centrifuge testing. A model single pile and two sets of 3 × 1 row model pile groups with different pile spacing were embedded in soft kaolin clay and tested under the action of model earthquakes at 50 times the earth’s gravity. The strength and stiffness of clay were evaluated using a T-bar test and an Air Hammer device respectively. The focus of this research is to investigate the dynamic response of friction piles in soft clay. However, this depends on the dynamic response of the soft clay layer around the pile. To this end, one-dimensional ground response analysis was performed using DEEPSOIL software to emphasise the importance of non-linear analysis in characterising the seismic behaviour of soft clays. It will be shown that clay response depends both on the earthquake intensity and the shear strength and stiffness of the clay layer. This has a direct bearing on the response of single piles and pile groups, with larger amplification occurring for small intensity earthquakes and attenuation occurring for stronger earthquakes.
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Seismic behaviour of soft clay and its influence on the response of friction pile foundations
Springer Nature, 2019Co-Authors: Thejesh Kumar Garala, Madabhushi GspAbstract:© 2018, The Author(s). In recent years, much of the research in geotechnical earthquake engineering has focused on liquefaction of loose, saturated sands and silts. However, the dynamic behaviour of soft, clayey soils and their interaction with pile foundations during the earthquakes have received relatively little attention. In this study, an attempt is made to investigate the dynamic behaviour of soft clay and its interaction with pile foundations during earthquakes using high gravity centrifuge testing. A model single pile and two sets of 3 × 1 row model pile groups with different pile spacing were embedded in soft kaolin clay and tested under the action of model earthquakes at 50 times the earth’s gravity. The strength and stiffness of clay were evaluated using a T-bar test and an Air Hammer device respectively. The focus of this research is to investigate the dynamic response of friction piles in soft clay. However, this depends on the dynamic response of the soft clay layer around the pile. To this end, one-dimensional ground response analysis was performed using DEEPSOIL software to emphasise the importance of non-linear analysis in characterising the seismic behaviour of soft clays. It will be shown that clay response depends both on the earthquake intensity and the shear strength and stiffness of the clay layer. This has a direct bearing on the response of single piles and pile groups, with larger amplification occurring for small intensity earthquakes and attenuation occurring for stronger earthquakes
Yongjiang Luo - One of the best experts on this subject based on the ideXlab platform.
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investigation of rc dth Air Hammer performance using cfd approach with dynamic mesh method
Journal of Advanced Research, 2019Co-Authors: Xinxin Zhang, Yongjiang Luo, Jianming Peng, Liming Fan, Kun YinAbstract:Abstract Reverse circulation down-the-hole (RC-DTH) Air Hammers have been widely used in construction and mining activities owing to their high drilling efficiency and good dust control performance. This paper presents a computational fluid dynamics (CFD) approach with the dynamic mesh method for evaluating the performance of RC-DTH Air Hammers. Nine stages of operating conditions of the RC-DTH Air Hammer are described herein to better understand the operating mechanism of the RC-DTH Air Hammer. Dynamic layering, sliding interfaces, as well as user-defined functions were employed to update the mesh in dynamic mesh modelling. The influences of rebound coefficient, input Air pressure, and piston mass on the performance of RC-DTH Air Hammers were studied. It was found that increasing the rebound coefficient and input Air pressure can improve the impact performance of RC-DTH Air Hammers, whereas increasing input Air pressure can reduce energy efficiency and increase energy consumption. In addition, simulation results indicate that increasing the input Air pressure may increase the stroke of the piston; the piston mass should be optimally selected to match the designed geometric parameters to avoid a significant drop in performance. The CFD approach with the dynamic mesh method shows superiority in evaluating the performance of RC-DTH Air Hammers.
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research on suction capacity and dust suppression performance of a reverse circulation Air Hammer in tunnel drilling
Tunnelling and Underground Space Technology, 2018Co-Authors: Bingxing Sun, Yunpei Liang, Yongjiang LuoAbstract:Abstract The presence of respirable dust in underground space causes serious health hazards for workers while in tunnel drilling, which could result in pneumoconiosis and silicosis. In order to control the dust dispersion and improve the environment quality of underground space while in tunnel drilling, an innovative drilling system with a reverse circulation (RC) Air Hammer is proposed. In addition, the structure of the RC Air Hammer with double-row suction nozzles is specially designed, which contributes to the improvement of suction capacity of the Air Hammer. Totally four structural parameters of the RC Air Hammer are optimized, and the effects of four structural parameters on suction capacity of the Air Hammer also have been investigated by means of Computational Fluid Dynamics (CFD) simulation method, which is crucial for the dust suppression performance of the RC Air Hammer drilling system. Simulation results have shown that the inclination angle ( θ s ) has the greatest influence on suction capacity among the four structural parameters, which is descendingly followed by the defection angle ( θ d ), the vertical space ( L ) and the horizontal space ( S ). Meanwhile, the optimal parameters configuration of the Air Hammer with double-row suction nozzles has been obtained. Additionally, the laboratory and field tests on the RC drilling system with optimal parameter configuration have been subsequently conducted, and no dust or rock cuttings were suspended in the underground space, which dramatically improves the internal working conditions of tunneling drilling. In conclusion, the suction capacity of the Air Hammer with optimized structural configuration is outstanding, and the dust suppression performance of the RC Air Hammer drilling system is excellent, which is applicable to eliminate the dust dispersion in underground tunnel drilling.
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development of a specially designed drill bit for down the hole Air Hammer to reduce dust production in the drilling process
Journal of Cleaner Production, 2016Co-Authors: Yongjiang Luo, Jianming Peng, Xin Gan, Kun Yin, Zhiqiang ZhaoAbstract:Abstract A specially structured drill bit is designed for a reverse circulation down-the-hole Air Hammer to reduce dust production in the local vicinity of the drilling site during operation. Computational fluid dynamics and experimental studies were conducted. Results show that the spray velocity of suction nozzles has an important effect on the performance of the drill bit for dust control. Three optimized drill bits were built for a GQ-89 reverse circulation down-the-hole Air Hammer and field-tested by drilling vertically downward boreholes in Xiao Qinling gold ore district. These drill bits have two mid-pressure restoring grooves with a diameter of 8 mm, two symmetrically placed flushing nozzles with diameter of 3 mm, and six uniformly distributed suction nozzles with diameter of 6 mm for each layer. Field tests show that employing the reverse circulation down-the-hole Air Hammer with specially designed drill bit has good dust control performance in the drilling processes. The specially designed drill bit can provide dust control efficiency of up to 99% with no need for additional sealing device, which is higher than both wet drilling and dry drilling by closing the drilling area. And employing reverse circulation down-the-hole Air Hammer with the current designed drill bit can efficiently protect drilling workers and equipment from threats of drilling dust. The usage of the specially designed drill bit has also significantly simplified the dust control apparatus for down-the-hole Air Hammer drilling method.
Zhiqiang Zhao - One of the best experts on this subject based on the ideXlab platform.
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development of a specially designed drill bit for down the hole Air Hammer to reduce dust production in the drilling process
Journal of Cleaner Production, 2016Co-Authors: Yongjiang Luo, Jianming Peng, Xin Gan, Kun Yin, Zhiqiang ZhaoAbstract:Abstract A specially structured drill bit is designed for a reverse circulation down-the-hole Air Hammer to reduce dust production in the local vicinity of the drilling site during operation. Computational fluid dynamics and experimental studies were conducted. Results show that the spray velocity of suction nozzles has an important effect on the performance of the drill bit for dust control. Three optimized drill bits were built for a GQ-89 reverse circulation down-the-hole Air Hammer and field-tested by drilling vertically downward boreholes in Xiao Qinling gold ore district. These drill bits have two mid-pressure restoring grooves with a diameter of 8 mm, two symmetrically placed flushing nozzles with diameter of 3 mm, and six uniformly distributed suction nozzles with diameter of 6 mm for each layer. Field tests show that employing the reverse circulation down-the-hole Air Hammer with specially designed drill bit has good dust control performance in the drilling processes. The specially designed drill bit can provide dust control efficiency of up to 99% with no need for additional sealing device, which is higher than both wet drilling and dry drilling by closing the drilling area. And employing reverse circulation down-the-hole Air Hammer with the current designed drill bit can efficiently protect drilling workers and equipment from threats of drilling dust. The usage of the specially designed drill bit has also significantly simplified the dust control apparatus for down-the-hole Air Hammer drilling method.
Kun Yin - One of the best experts on this subject based on the ideXlab platform.
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investigation of rc dth Air Hammer performance using cfd approach with dynamic mesh method
Journal of Advanced Research, 2019Co-Authors: Xinxin Zhang, Yongjiang Luo, Jianming Peng, Liming Fan, Kun YinAbstract:Abstract Reverse circulation down-the-hole (RC-DTH) Air Hammers have been widely used in construction and mining activities owing to their high drilling efficiency and good dust control performance. This paper presents a computational fluid dynamics (CFD) approach with the dynamic mesh method for evaluating the performance of RC-DTH Air Hammers. Nine stages of operating conditions of the RC-DTH Air Hammer are described herein to better understand the operating mechanism of the RC-DTH Air Hammer. Dynamic layering, sliding interfaces, as well as user-defined functions were employed to update the mesh in dynamic mesh modelling. The influences of rebound coefficient, input Air pressure, and piston mass on the performance of RC-DTH Air Hammers were studied. It was found that increasing the rebound coefficient and input Air pressure can improve the impact performance of RC-DTH Air Hammers, whereas increasing input Air pressure can reduce energy efficiency and increase energy consumption. In addition, simulation results indicate that increasing the input Air pressure may increase the stroke of the piston; the piston mass should be optimally selected to match the designed geometric parameters to avoid a significant drop in performance. The CFD approach with the dynamic mesh method shows superiority in evaluating the performance of RC-DTH Air Hammers.
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development of a specially designed drill bit for down the hole Air Hammer to reduce dust production in the drilling process
Journal of Cleaner Production, 2016Co-Authors: Yongjiang Luo, Jianming Peng, Xin Gan, Kun Yin, Zhiqiang ZhaoAbstract:Abstract A specially structured drill bit is designed for a reverse circulation down-the-hole Air Hammer to reduce dust production in the local vicinity of the drilling site during operation. Computational fluid dynamics and experimental studies were conducted. Results show that the spray velocity of suction nozzles has an important effect on the performance of the drill bit for dust control. Three optimized drill bits were built for a GQ-89 reverse circulation down-the-hole Air Hammer and field-tested by drilling vertically downward boreholes in Xiao Qinling gold ore district. These drill bits have two mid-pressure restoring grooves with a diameter of 8 mm, two symmetrically placed flushing nozzles with diameter of 3 mm, and six uniformly distributed suction nozzles with diameter of 6 mm for each layer. Field tests show that employing the reverse circulation down-the-hole Air Hammer with specially designed drill bit has good dust control performance in the drilling processes. The specially designed drill bit can provide dust control efficiency of up to 99% with no need for additional sealing device, which is higher than both wet drilling and dry drilling by closing the drilling area. And employing reverse circulation down-the-hole Air Hammer with the current designed drill bit can efficiently protect drilling workers and equipment from threats of drilling dust. The usage of the specially designed drill bit has also significantly simplified the dust control apparatus for down-the-hole Air Hammer drilling method.