The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Jun Otani - One of the best experts on this subject based on the ideXlab platform.
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Image analysis of soil failure on defective Underground Pipe due to cyclic water supply and drainage using X-ray CT
Frontiers of Structural and Civil Engineering, 2012Co-Authors: Toshifumi Mukunoki, Naoko Kumano, Jun OtaniAbstract:The ground subsidence on the Underground Pipe often is caused with the reduction of the effective stress and the loss of suction in the base course and then, soil drainage into the Pipe. The final formation of the cavity growth in the ground was observed as the ground subsidence. Authors focused this problem and hence performed model tests with water-inflow and drainage cycle in the model ground. The mechanism of cavity generation in the model ground was observed using an X-ray Computed Tomography (CT) scanner. In those studies, water was supplied into the model grounds from the defected Underground Pipe model in case of the change of relative density and grain size distribution. As results, it was observed that the loosening area was generated from the defected part with water-inflow and some of the soil particles in the ground were drained into the Underground Pipe through the defected part. And afterward, the cavity was generated just above the defected part of the model Pipe in the ground. Based on this observation, it might be said that the bulk density of soil around the defected Pipe played one of key factor to generate the cavity in the ground. Moreover, the dimension of the defected part should be related to the magnification of the ground subsidence, in particular, crack width on a sewerage Pipe and particle size would be the quantitative factor to evaluate the magnification of the ground subsidence.
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Image analysis of soil failure on defective Underground Pipe due to cyclic water supply and drainage using X-ray CT
Frontiers of Structural and Civil Engineering, 2012Co-Authors: Toshifumi Mukunoki, Naoko Kumano, Jun OtaniAbstract:The ground subsidence on the Underground Pipe often is caused with the reduction of the effective stress and the loss of suction in the base course and then, soil drainage into the Pipe. The final formation of the cavity growth in the ground was observed as the ground subsidence. Authors focused this problem and hence performed model tests with water-inflow and drainage cycle in the model ground. The mechanism of cavity generation in the model ground was observed using an X-ray Computed Tomography (CT) scanner. In those studies, water was supplied into the model grounds from the defected Underground Pipe model in case of the change of relative density and grain size distribution. As results, it was observed that the loosening area was generated from the defected part with water-inflow and some of the soil particles in the ground were drained into the Underground Pipe through the defected part. And afterward, the cavity was generated just above the defected part of the model Pipe in the ground. Based on this observation, it might be said that the bulk density of soil around the defected Pipe played one of key factor to generate the cavity in the ground. Moreover, the dimension of the defected part should be related to the magnification of the ground subsidence, in particular, crack width on a sewerage Pipe and particle size would be the quantitative factor to evaluate the magnification of the ground subsidence. In this paper, it was concluded that the low relative density of soil would become the critical factor to cause the fatal failure of model ground if the maximum grain size was close to the dimension of crack width of defective part. The fatal collapse of the ground with high relative density more than 80% would be avoided in a few cycles of water inflow and soil drainage.
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visualization of three dimensional failure in sand due to water inflow and soil drainage from defective Underground Pipe using x ray ct
Soils and Foundations, 2009Co-Authors: Toshifumi Mukunoki, Naoko Kumano, Jun Otani, Reiko KuwanoAbstract:The roadway surface locally subsides due to material aging or settlement of a base course in particular, resulting in failure of the ground with a plenty of water inflow. In most cases of roadway subsidence, Underground Pipes exist underneath the subsidence. In order to understand significant factors leading to local subsidence at a ground surface, a series of model tests using sandy soil were performed with the concerned defect configuration of the Underground Pipe and hydraulic condition. An industrial X-ray computed tomography (CT) scanner was used to investigate the behaviour of the model ground at each step of monotonic water inflow, monotonic soil drainage and the cyclic water inflow—soil drainage. Then, the behaviour density change of the model ground was visualized as a density change in two-dimensions and three-dimension. This paper concludes that the cyclic condition of water inflow—soil drainage caused fatal ground failure as the water inflow process created a water path disturbing the soil. Subsequently, the soil drained and the soil particles were interlocked due to the drainage. The movement of soil particles were restricted with the arching effect; and, the factors causing the cavity in the ground were not only the existing defect in the Underground Pipe but also the water flow towards the defective part after the loss of capillary force.
Toshifumi Mukunoki - One of the best experts on this subject based on the ideXlab platform.
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Image analysis of soil failure on defective Underground Pipe due to cyclic water supply and drainage using X-ray CT
Frontiers of Structural and Civil Engineering, 2012Co-Authors: Toshifumi Mukunoki, Naoko Kumano, Jun OtaniAbstract:The ground subsidence on the Underground Pipe often is caused with the reduction of the effective stress and the loss of suction in the base course and then, soil drainage into the Pipe. The final formation of the cavity growth in the ground was observed as the ground subsidence. Authors focused this problem and hence performed model tests with water-inflow and drainage cycle in the model ground. The mechanism of cavity generation in the model ground was observed using an X-ray Computed Tomography (CT) scanner. In those studies, water was supplied into the model grounds from the defected Underground Pipe model in case of the change of relative density and grain size distribution. As results, it was observed that the loosening area was generated from the defected part with water-inflow and some of the soil particles in the ground were drained into the Underground Pipe through the defected part. And afterward, the cavity was generated just above the defected part of the model Pipe in the ground. Based on this observation, it might be said that the bulk density of soil around the defected Pipe played one of key factor to generate the cavity in the ground. Moreover, the dimension of the defected part should be related to the magnification of the ground subsidence, in particular, crack width on a sewerage Pipe and particle size would be the quantitative factor to evaluate the magnification of the ground subsidence.
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Image analysis of soil failure on defective Underground Pipe due to cyclic water supply and drainage using X-ray CT
Frontiers of Structural and Civil Engineering, 2012Co-Authors: Toshifumi Mukunoki, Naoko Kumano, Jun OtaniAbstract:The ground subsidence on the Underground Pipe often is caused with the reduction of the effective stress and the loss of suction in the base course and then, soil drainage into the Pipe. The final formation of the cavity growth in the ground was observed as the ground subsidence. Authors focused this problem and hence performed model tests with water-inflow and drainage cycle in the model ground. The mechanism of cavity generation in the model ground was observed using an X-ray Computed Tomography (CT) scanner. In those studies, water was supplied into the model grounds from the defected Underground Pipe model in case of the change of relative density and grain size distribution. As results, it was observed that the loosening area was generated from the defected part with water-inflow and some of the soil particles in the ground were drained into the Underground Pipe through the defected part. And afterward, the cavity was generated just above the defected part of the model Pipe in the ground. Based on this observation, it might be said that the bulk density of soil around the defected Pipe played one of key factor to generate the cavity in the ground. Moreover, the dimension of the defected part should be related to the magnification of the ground subsidence, in particular, crack width on a sewerage Pipe and particle size would be the quantitative factor to evaluate the magnification of the ground subsidence. In this paper, it was concluded that the low relative density of soil would become the critical factor to cause the fatal failure of model ground if the maximum grain size was close to the dimension of crack width of defective part. The fatal collapse of the ground with high relative density more than 80% would be avoided in a few cycles of water inflow and soil drainage.
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visualization of three dimensional failure in sand due to water inflow and soil drainage from defective Underground Pipe using x ray ct
Soils and Foundations, 2009Co-Authors: Toshifumi Mukunoki, Naoko Kumano, Jun Otani, Reiko KuwanoAbstract:The roadway surface locally subsides due to material aging or settlement of a base course in particular, resulting in failure of the ground with a plenty of water inflow. In most cases of roadway subsidence, Underground Pipes exist underneath the subsidence. In order to understand significant factors leading to local subsidence at a ground surface, a series of model tests using sandy soil were performed with the concerned defect configuration of the Underground Pipe and hydraulic condition. An industrial X-ray computed tomography (CT) scanner was used to investigate the behaviour of the model ground at each step of monotonic water inflow, monotonic soil drainage and the cyclic water inflow—soil drainage. Then, the behaviour density change of the model ground was visualized as a density change in two-dimensions and three-dimension. This paper concludes that the cyclic condition of water inflow—soil drainage caused fatal ground failure as the water inflow process created a water path disturbing the soil. Subsequently, the soil drained and the soil particles were interlocked due to the drainage. The movement of soil particles were restricted with the arching effect; and, the factors causing the cavity in the ground were not only the existing defect in the Underground Pipe but also the water flow towards the defective part after the loss of capillary force.
Naoko Kumano - One of the best experts on this subject based on the ideXlab platform.
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Image analysis of soil failure on defective Underground Pipe due to cyclic water supply and drainage using X-ray CT
Frontiers of Structural and Civil Engineering, 2012Co-Authors: Toshifumi Mukunoki, Naoko Kumano, Jun OtaniAbstract:The ground subsidence on the Underground Pipe often is caused with the reduction of the effective stress and the loss of suction in the base course and then, soil drainage into the Pipe. The final formation of the cavity growth in the ground was observed as the ground subsidence. Authors focused this problem and hence performed model tests with water-inflow and drainage cycle in the model ground. The mechanism of cavity generation in the model ground was observed using an X-ray Computed Tomography (CT) scanner. In those studies, water was supplied into the model grounds from the defected Underground Pipe model in case of the change of relative density and grain size distribution. As results, it was observed that the loosening area was generated from the defected part with water-inflow and some of the soil particles in the ground were drained into the Underground Pipe through the defected part. And afterward, the cavity was generated just above the defected part of the model Pipe in the ground. Based on this observation, it might be said that the bulk density of soil around the defected Pipe played one of key factor to generate the cavity in the ground. Moreover, the dimension of the defected part should be related to the magnification of the ground subsidence, in particular, crack width on a sewerage Pipe and particle size would be the quantitative factor to evaluate the magnification of the ground subsidence.
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Image analysis of soil failure on defective Underground Pipe due to cyclic water supply and drainage using X-ray CT
Frontiers of Structural and Civil Engineering, 2012Co-Authors: Toshifumi Mukunoki, Naoko Kumano, Jun OtaniAbstract:The ground subsidence on the Underground Pipe often is caused with the reduction of the effective stress and the loss of suction in the base course and then, soil drainage into the Pipe. The final formation of the cavity growth in the ground was observed as the ground subsidence. Authors focused this problem and hence performed model tests with water-inflow and drainage cycle in the model ground. The mechanism of cavity generation in the model ground was observed using an X-ray Computed Tomography (CT) scanner. In those studies, water was supplied into the model grounds from the defected Underground Pipe model in case of the change of relative density and grain size distribution. As results, it was observed that the loosening area was generated from the defected part with water-inflow and some of the soil particles in the ground were drained into the Underground Pipe through the defected part. And afterward, the cavity was generated just above the defected part of the model Pipe in the ground. Based on this observation, it might be said that the bulk density of soil around the defected Pipe played one of key factor to generate the cavity in the ground. Moreover, the dimension of the defected part should be related to the magnification of the ground subsidence, in particular, crack width on a sewerage Pipe and particle size would be the quantitative factor to evaluate the magnification of the ground subsidence. In this paper, it was concluded that the low relative density of soil would become the critical factor to cause the fatal failure of model ground if the maximum grain size was close to the dimension of crack width of defective part. The fatal collapse of the ground with high relative density more than 80% would be avoided in a few cycles of water inflow and soil drainage.
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visualization of three dimensional failure in sand due to water inflow and soil drainage from defective Underground Pipe using x ray ct
Soils and Foundations, 2009Co-Authors: Toshifumi Mukunoki, Naoko Kumano, Jun Otani, Reiko KuwanoAbstract:The roadway surface locally subsides due to material aging or settlement of a base course in particular, resulting in failure of the ground with a plenty of water inflow. In most cases of roadway subsidence, Underground Pipes exist underneath the subsidence. In order to understand significant factors leading to local subsidence at a ground surface, a series of model tests using sandy soil were performed with the concerned defect configuration of the Underground Pipe and hydraulic condition. An industrial X-ray computed tomography (CT) scanner was used to investigate the behaviour of the model ground at each step of monotonic water inflow, monotonic soil drainage and the cyclic water inflow—soil drainage. Then, the behaviour density change of the model ground was visualized as a density change in two-dimensions and three-dimension. This paper concludes that the cyclic condition of water inflow—soil drainage caused fatal ground failure as the water inflow process created a water path disturbing the soil. Subsequently, the soil drained and the soil particles were interlocked due to the drainage. The movement of soil particles were restricted with the arching effect; and, the factors causing the cavity in the ground were not only the existing defect in the Underground Pipe but also the water flow towards the defective part after the loss of capillary force.
Yang Zhuan-yun - One of the best experts on this subject based on the ideXlab platform.
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3D FEM Analysis of Subgrade Soil Movement and Deformation Caused by Extra-Shallow-Underground-Pipe Jacking
Journal of Chongqing Jianzhu University, 2020Co-Authors: Yang Zhuan-yunAbstract:Pavement structures will be damaged by subgrade soil movement around the Pipes introduced by extra-shallow-Underground-Pipe jacking.Soil layer deformation with shallow deposits on Pipes during extra-shallow-Underground-Pipe jacking is analyzed using 3D FEM.The effects on pavement deformation created by the friction between shield and soil,injection slurry,jacking forces and the vehicle loads are studied with a practical project.The analytical results show that the ground surface deformation is an uplift first followed by settling with the lower part of the cover moving faster than the upper layers.It is demonstrated by comparing computational results of FEM simulation and the observed data from the in-situ test that these FEM models can be applied to real-world engineering.Subgrade soil settling on extra-shallow-Underground-Pipe jacking in a cross-section will be stable when the shield has passed through a section with a length twice the diameter of the Pipe.Horizontal surface subsidence along the lateral distribution is similar to a normal distribution curve,with the primary affected areas on both sides of the axis approximately 1.5 times the diameter of the Pipe.
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Construction Techniques of Working Shaft for Ultra-shallow-Underground-Pipe Jacking
2020Co-Authors: Yang Zhuan-yunAbstract:In construction of Pipe jacking,the wall of working shaft and soil body behind the sidewall offers enormous supporting force to a lift.But for ultra-shallow-Underground-Pipe jacking,the limited discrepancy between ground level and the bottom level of the shaft produces the difficulty for the designing and construction.The paper detailed construction technology of working shaft for Pipe jacking in ultra-shallow shaft with a practical engineering,including some key points of pre-grouting,ring beam construction and top-down construction methods.
Reiko Kuwano - One of the best experts on this subject based on the ideXlab platform.
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visualization of three dimensional failure in sand due to water inflow and soil drainage from defective Underground Pipe using x ray ct
Soils and Foundations, 2009Co-Authors: Toshifumi Mukunoki, Naoko Kumano, Jun Otani, Reiko KuwanoAbstract:The roadway surface locally subsides due to material aging or settlement of a base course in particular, resulting in failure of the ground with a plenty of water inflow. In most cases of roadway subsidence, Underground Pipes exist underneath the subsidence. In order to understand significant factors leading to local subsidence at a ground surface, a series of model tests using sandy soil were performed with the concerned defect configuration of the Underground Pipe and hydraulic condition. An industrial X-ray computed tomography (CT) scanner was used to investigate the behaviour of the model ground at each step of monotonic water inflow, monotonic soil drainage and the cyclic water inflow—soil drainage. Then, the behaviour density change of the model ground was visualized as a density change in two-dimensions and three-dimension. This paper concludes that the cyclic condition of water inflow—soil drainage caused fatal ground failure as the water inflow process created a water path disturbing the soil. Subsequently, the soil drained and the soil particles were interlocked due to the drainage. The movement of soil particles were restricted with the arching effect; and, the factors causing the cavity in the ground were not only the existing defect in the Underground Pipe but also the water flow towards the defective part after the loss of capillary force.
