A full-scale reinforced earth embankment was designed and constructed by the
Department of Highwa... more A full-scale reinforced earth embankment was designed and constructed by the Department of Highways of Thailand on a hard foundation in Phitsanulok Province, Thailand. Two types of reinforcement were used in the embankment. One side was reinforced with polymeric reinforcement consisting of polyester (PET), polypropylene (PP) and high-density polyethylene (HDPE) and referred to as a reinforced steep slope (RSS), with an angle of 70° from horizontal. On the other side, the embankment was reinforced with metallic reinforcement consisting of metallic strips (MS) and steel wire grids (SWG) combined with vertical segmental concrete facing and referred to as a mechanically stabilised earth wall (MSEW). The behaviour of the reinforced soil slope and the mechanically stabilised earth wall on a hard foundation were observed and compared with predictions from the PLAXIS 3D software. The lateral displacements and settlements were very small in the case of the MSEW with inextensible reinforcement. The corresponding lateral and vertical deformations in the RSS were much larger due to its extensible reinforcing materials. The stiffnesses of the reinforcing materials decrease in the following order: MS, SWG, PP, HDPE and PET. The results obtained from three-dimensional (3D) finite element method simulations (using PLAXIS 3D) were in good agreement with the field measurements in terms of vertical and lateral deformations and strains in the reinforcement.
A full scale reinforced test embankment was designed and constructed by Department of Highways (D... more A full scale reinforced test embankment was designed and constructed by Department of Highways (DOH) on hard foundation (i.e. Soil stratum containing relatively stiff to very stiff clay) in Phitsanulok Province, Thailand. Two types of reinforcements were used. One side, called reinforced steep slope (RSS) with folded polymer facing at an angle of 70 degrees from the horizontal, was reinforced with polymeric reinforcements consisting of polyester (PET), polypropylene (PP) and high density polyethelene (HDPE). The other side, called mechanically stabilized earth wall (MSEW) with vertical segmental concrete facing, was reinforced with metallic reinforcement consisting of metallic strips (MS) and steel wire grids (SWG). The behaviour of the RSS and MSEW slopes were observed, back-analysed by sensitivity analysis and compared with the predictions from FEM PLAXIS 3D simulations. As expected the vertical settlements were very small for the hard foundation. The corresponding lateral movemen...
A full scale test embankment (6 m height) was constructed by Department of Highways, the Bureau o... more A full scale test embankment (6 m height) was constructed by Department of Highways, the Bureau of Road Research and Development in Phitsanulok, Thailand. A surcharge fill of 1.2 m thick without reinforcements was added at the top of the embankment equivalent to 2 tsm of load. One side of this embankment was reinforced with polymeric reinforcements consisting polyester (PET), polypropylene (PP) and high density polyethylene (HDPE) and referred as reinforced steep slope (RSS), which is at an angle of 70 degrees from horizontal. The other side of the embankment was reinforced with metallic reinforcements consisting of metallic strips (MS) and steel wire grids (SWG) combined with precast concrete panel and termed as mechanically stabilized earth wall (MSEW). The comparisons of these reinforcing materials in terms of stiffness from highest to lowest are metallic strip (MS), steel wire grids (SWG), polypropylene (PP), high density polyethylene (HDPE) and polyester (PET). The behavior of ...
ABSTRACT This paper presents the result of laboratory model tests using water hyacinth limited li... more ABSTRACT This paper presents the result of laboratory model tests using water hyacinth limited life geotextiles (LLGs) as well as using Vetiver and Ruzi grasses for erosion control. The mass per unit area and tensile strength of water hyacinth LLGs were obtained. The tensile properties of Ruzi and Vetiver grass roots were obtained after growing periods of 2, 3, 4, 5 and 6 months. Moreover, the rainfall effects were conducted in the laboratory model tests for the erosion control tests. Lateritic soil and sandy soil were investigated separately with LLGs and vegetation covers. Water hyacinth LLGs with opening size 8 mm by 8 mm and 12 mm by 12 mm was used to cover the bare soil. Ruzi and Vetiver grasses were planted in the container and tested at the age of 4, 6, 8 weeks, respectively. The model slope angle of 1H:1V, 2H:1V and 3H:1V were used for the tests. The maximum rainfall intensity used in this study was 120 mm/h which normally occurs in Thailand. The runoff rate and soil loss were used to measure the soil erosion. The results shows that the soil loss and runoff rate of lateritic soil were higher than sandy soil. Furthermore, the steeper slopes of 1H:1V yielded highest runoff rate and soil loss than flatter slopes of 2H:1V and 3H:1V. Slope 3H:1V with vegetation cover had the highest resistance to erosion. Generally, bare soil with woven LLGs 12 mm by 12 mm opening size resulted in less amount of runoff rate than 8 mm by 8 mm opening size for both soil types. In contrast, bare soil with LLGs 12 mm by 12 mm indicated higher soil loss than 8 mm by 8 mm opening size for both soil types. Additionally, the bare soil with Ruzi grass reduced the amount of runoff rate and soil loss than Vetiver grass. The combination of Ruzi and Vetiver grasses with lateritic soil can produce the best runoff rate and soil loss yield with slope 3H:1V. As slopes become steeper the surface runoff increased. The increasing growing periods at 4, 6, 8 weeks of Vetiver and Ruzi grasses reduced the amount of soil loss and surface runoff because of increasing coverage of vegetation. The observed data indicated the important role of vegetation in soil erosion prevention at different slope inclinations. The combination of Vetiver and Ruzi grass was highly effective against soil erosion and reducing the runoff rate.
A full-scale reinforced earth embankment was designed and constructed by the
Department of Highwa... more A full-scale reinforced earth embankment was designed and constructed by the Department of Highways of Thailand on a hard foundation in Phitsanulok Province, Thailand. Two types of reinforcement were used in the embankment. One side was reinforced with polymeric reinforcement consisting of polyester (PET), polypropylene (PP) and high-density polyethylene (HDPE) and referred to as a reinforced steep slope (RSS), with an angle of 70° from horizontal. On the other side, the embankment was reinforced with metallic reinforcement consisting of metallic strips (MS) and steel wire grids (SWG) combined with vertical segmental concrete facing and referred to as a mechanically stabilised earth wall (MSEW). The behaviour of the reinforced soil slope and the mechanically stabilised earth wall on a hard foundation were observed and compared with predictions from the PLAXIS 3D software. The lateral displacements and settlements were very small in the case of the MSEW with inextensible reinforcement. The corresponding lateral and vertical deformations in the RSS were much larger due to its extensible reinforcing materials. The stiffnesses of the reinforcing materials decrease in the following order: MS, SWG, PP, HDPE and PET. The results obtained from three-dimensional (3D) finite element method simulations (using PLAXIS 3D) were in good agreement with the field measurements in terms of vertical and lateral deformations and strains in the reinforcement.
A full scale reinforced test embankment was designed and constructed by Department of Highways (D... more A full scale reinforced test embankment was designed and constructed by Department of Highways (DOH) on hard foundation (i.e. Soil stratum containing relatively stiff to very stiff clay) in Phitsanulok Province, Thailand. Two types of reinforcements were used. One side, called reinforced steep slope (RSS) with folded polymer facing at an angle of 70 degrees from the horizontal, was reinforced with polymeric reinforcements consisting of polyester (PET), polypropylene (PP) and high density polyethelene (HDPE). The other side, called mechanically stabilized earth wall (MSEW) with vertical segmental concrete facing, was reinforced with metallic reinforcement consisting of metallic strips (MS) and steel wire grids (SWG). The behaviour of the RSS and MSEW slopes were observed, back-analysed by sensitivity analysis and compared with the predictions from FEM PLAXIS 3D simulations. As expected the vertical settlements were very small for the hard foundation. The corresponding lateral movemen...
A full scale test embankment (6 m height) was constructed by Department of Highways, the Bureau o... more A full scale test embankment (6 m height) was constructed by Department of Highways, the Bureau of Road Research and Development in Phitsanulok, Thailand. A surcharge fill of 1.2 m thick without reinforcements was added at the top of the embankment equivalent to 2 tsm of load. One side of this embankment was reinforced with polymeric reinforcements consisting polyester (PET), polypropylene (PP) and high density polyethylene (HDPE) and referred as reinforced steep slope (RSS), which is at an angle of 70 degrees from horizontal. The other side of the embankment was reinforced with metallic reinforcements consisting of metallic strips (MS) and steel wire grids (SWG) combined with precast concrete panel and termed as mechanically stabilized earth wall (MSEW). The comparisons of these reinforcing materials in terms of stiffness from highest to lowest are metallic strip (MS), steel wire grids (SWG), polypropylene (PP), high density polyethylene (HDPE) and polyester (PET). The behavior of ...
ABSTRACT This paper presents the result of laboratory model tests using water hyacinth limited li... more ABSTRACT This paper presents the result of laboratory model tests using water hyacinth limited life geotextiles (LLGs) as well as using Vetiver and Ruzi grasses for erosion control. The mass per unit area and tensile strength of water hyacinth LLGs were obtained. The tensile properties of Ruzi and Vetiver grass roots were obtained after growing periods of 2, 3, 4, 5 and 6 months. Moreover, the rainfall effects were conducted in the laboratory model tests for the erosion control tests. Lateritic soil and sandy soil were investigated separately with LLGs and vegetation covers. Water hyacinth LLGs with opening size 8 mm by 8 mm and 12 mm by 12 mm was used to cover the bare soil. Ruzi and Vetiver grasses were planted in the container and tested at the age of 4, 6, 8 weeks, respectively. The model slope angle of 1H:1V, 2H:1V and 3H:1V were used for the tests. The maximum rainfall intensity used in this study was 120 mm/h which normally occurs in Thailand. The runoff rate and soil loss were used to measure the soil erosion. The results shows that the soil loss and runoff rate of lateritic soil were higher than sandy soil. Furthermore, the steeper slopes of 1H:1V yielded highest runoff rate and soil loss than flatter slopes of 2H:1V and 3H:1V. Slope 3H:1V with vegetation cover had the highest resistance to erosion. Generally, bare soil with woven LLGs 12 mm by 12 mm opening size resulted in less amount of runoff rate than 8 mm by 8 mm opening size for both soil types. In contrast, bare soil with LLGs 12 mm by 12 mm indicated higher soil loss than 8 mm by 8 mm opening size for both soil types. Additionally, the bare soil with Ruzi grass reduced the amount of runoff rate and soil loss than Vetiver grass. The combination of Ruzi and Vetiver grasses with lateritic soil can produce the best runoff rate and soil loss yield with slope 3H:1V. As slopes become steeper the surface runoff increased. The increasing growing periods at 4, 6, 8 weeks of Vetiver and Ruzi grasses reduced the amount of soil loss and surface runoff because of increasing coverage of vegetation. The observed data indicated the important role of vegetation in soil erosion prevention at different slope inclinations. The combination of Vetiver and Ruzi grass was highly effective against soil erosion and reducing the runoff rate.
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Department of Highways of Thailand on a hard foundation in Phitsanulok Province,
Thailand. Two types of reinforcement were used in the embankment. One side was
reinforced with polymeric reinforcement consisting of polyester (PET), polypropylene
(PP) and high-density polyethylene (HDPE) and referred to as a reinforced steep slope
(RSS), with an angle of 70° from horizontal. On the other side, the embankment was
reinforced with metallic reinforcement consisting of metallic strips (MS) and steel wire
grids (SWG) combined with vertical segmental concrete facing and referred to as a
mechanically stabilised earth wall (MSEW). The behaviour of the reinforced soil slope
and the mechanically stabilised earth wall on a hard foundation were observed and
compared with predictions from the PLAXIS 3D software. The lateral displacements
and settlements were very small in the case of the MSEW with inextensible reinforcement.
The corresponding lateral and vertical deformations in the RSS were much larger
due to its extensible reinforcing materials. The stiffnesses of the reinforcing materials
decrease in the following order: MS, SWG, PP, HDPE and PET. The results obtained from
three-dimensional (3D) finite element method simulations (using PLAXIS 3D) were in
good agreement with the field measurements in terms of vertical and lateral deformations
and strains in the reinforcement.
Department of Highways of Thailand on a hard foundation in Phitsanulok Province,
Thailand. Two types of reinforcement were used in the embankment. One side was
reinforced with polymeric reinforcement consisting of polyester (PET), polypropylene
(PP) and high-density polyethylene (HDPE) and referred to as a reinforced steep slope
(RSS), with an angle of 70° from horizontal. On the other side, the embankment was
reinforced with metallic reinforcement consisting of metallic strips (MS) and steel wire
grids (SWG) combined with vertical segmental concrete facing and referred to as a
mechanically stabilised earth wall (MSEW). The behaviour of the reinforced soil slope
and the mechanically stabilised earth wall on a hard foundation were observed and
compared with predictions from the PLAXIS 3D software. The lateral displacements
and settlements were very small in the case of the MSEW with inextensible reinforcement.
The corresponding lateral and vertical deformations in the RSS were much larger
due to its extensible reinforcing materials. The stiffnesses of the reinforcing materials
decrease in the following order: MS, SWG, PP, HDPE and PET. The results obtained from
three-dimensional (3D) finite element method simulations (using PLAXIS 3D) were in
good agreement with the field measurements in terms of vertical and lateral deformations
and strains in the reinforcement.