If adopted high preload in the struts braced excavation?
Pre-loading in the struts braced excavation helps eliminate potential movement. The use of preload reduces the shear stress in the soil, previously established by the excavation. Because of the rigidity of the soil, they can use high preload the struts are not desirable, because the movement of strut local departure could cause damage to public services nearby.
For Peck, the pressure boundary of braced excavation, the total weight or actual weight used in the trapezoidal and rectangular envelope?
Asset utilization and rest the theory is not applicable in the braced excavation. Basically spacers higher tendency to be more crowded, while lower spacers appear to be less responsible in comparison with the theory of the pressure force.
Peck measured reinforcement loads are converted to the pressure of the earth. For example, the limit of the pressure of cohesionless soils is 0.65rHKa
where
r = soil density
H = height of the excavation
Ka = coefficient of active pressure
Some engineers consider r the total weight of the soil to apply any pressure. However, Peck said, "the pressures are not substantially affect the coefficient of active earth pressure and redistribution of
rectangle or a trapezoid. "So an effective weight of soil to use for r the pressure of water is added separately.
The excavation was prepared, why Rankine's theory of lateral earth pressure is not applied?
The excavation was prepared, piling was built first, followed by the installation of braces, as a result of the excavations. After installing the first row of tabs, the depth of excavation is small, so that there is a great performance from the earth. However, as the excavation takes place, the performance of the ground before installing the line number of the spacers. The first row of slats prevents the transfer of near surface. Therefore, the deformation of the walls increases with depth with the lowest land. Because of the effect of the construction method of excavation was prepared, unlike the condition of deformation of the Rankine theory. This is attributed to the effects of the ark in which there is a redistribution of loads up. The top of the excavation will be mounted in the state of elastic equilibrium, while the fund is in a state of plastic equilibrium.
What is the difference between the method of the land of free technical support and method fixed earth support?
Pre-loading in the struts braced excavation helps eliminate potential movement. The use of preload reduces the shear stress in the soil, previously established by the excavation. Because of the rigidity of the soil, they can use high preload the struts are not desirable, because the movement of strut local departure could cause damage to public services nearby.
For Peck, the pressure boundary of braced excavation, the total weight or actual weight used in the trapezoidal and rectangular envelope?
Asset utilization and rest the theory is not applicable in the braced excavation. Basically spacers higher tendency to be more crowded, while lower spacers appear to be less responsible in comparison with the theory of the pressure force.
Peck measured reinforcement loads are converted to the pressure of the earth. For example, the limit of the pressure of cohesionless soils is 0.65rHKa
where
r = soil density
H = height of the excavation
Ka = coefficient of active pressure
Some engineers consider r the total weight of the soil to apply any pressure. However, Peck said, "the pressures are not substantially affect the coefficient of active earth pressure and redistribution of
rectangle or a trapezoid. "So an effective weight of soil to use for r the pressure of water is added separately.
The excavation was prepared, why Rankine's theory of lateral earth pressure is not applied?
The excavation was prepared, piling was built first, followed by the installation of braces, as a result of the excavations. After installing the first row of tabs, the depth of excavation is small, so that there is a great performance from the earth. However, as the excavation takes place, the performance of the ground before installing the line number of the spacers. The first row of slats prevents the transfer of near surface. Therefore, the deformation of the walls increases with depth with the lowest land. Because of the effect of the construction method of excavation was prepared, unlike the condition of deformation of the Rankine theory. This is attributed to the effects of the ark in which there is a redistribution of loads up. The top of the excavation will be mounted in the state of elastic equilibrium, while the fund is in a state of plastic equilibrium.
What is the difference between the method of the land of free technical support and method fixed earth support?
For free earth support method, the soils at the lower part of piling is incapable of inducing effective restraint so that it would not result in negative bending moments. In essence, the passive pressures in front of the sheet piles are insufficient to prevent lateral deflection and rotations at the lower end of piling. No passive resistance is developed on the backside of the piling below the line of excavation.
For fixed earth support method, the piling is driven deep enough so that the soil under the line of excavation provides the required restraint against deformations and rotations. In short, the lower end of piling is essentially fixed. Is bleeding to test a prerequisite for the grout?
Bleeding is a form of segregation, where a layer of water migrates to the surface of the grout in the initial phase of the process of cement hydration. Later, some liquid water reabsorbed in the grout due to additional hydration reactions. Even without the problem of bleeding, there is an overall reduction in the volume of grout after treatment of hydration compared to the total individual initial reaction of cement and water. Bleeding tests should be performed to grout for the following reasons:
(I) During the riser duct bleeding water from the mixture of slurry to the formation of channel paths inside the grout mixture. These channels act as potential pathways for materials to go aggressive, because these
channels would not be closed when the additional hydration of the grout.
(Ii) the loss of volume by bleeding inside the product shall render the milk mixture affecting the properties and performance of the grout. It also increases the possibility of corrosion of steel elements protected by the grout. (Tendons, etc.)
(Iii) The test of bleeding, there is a usual requirement for a total re-absorption of water after 24 hours the composition of the grout, because for some cold countries, this layer of water, causing serious problems freezing, leading to freezing.
The presence of colluvial slopes good?
Bleeding is a form of segregation, where a layer of water migrates to the surface of the grout in the initial phase of the process of cement hydration. Later, some liquid water reabsorbed in the grout due to additional hydration reactions. Even without the problem of bleeding, there is an overall reduction in the volume of grout after treatment of hydration compared to the total individual initial reaction of cement and water. Bleeding tests should be performed to grout for the following reasons:
(I) During the riser duct bleeding water from the mixture of slurry to the formation of channel paths inside the grout mixture. These channels act as potential pathways for materials to go aggressive, because these
channels would not be closed when the additional hydration of the grout.
(Ii) the loss of volume by bleeding inside the product shall render the milk mixture affecting the properties and performance of the grout. It also increases the possibility of corrosion of steel elements protected by the grout. (Tendons, etc.)
(Iii) The test of bleeding, there is a usual requirement for a total re-absorption of water after 24 hours the composition of the grout, because for some cold countries, this layer of water, causing serious problems freezing, leading to freezing.
The presence of colluvial slopes good?
Colluvium refer to the deposit same area running down the mountain slopes under the influence of gravity. It differs from the remaining land, degradation of the discontinuity, part of the textures preserved. The rolling action colluvium destroy these features.
Colluvium shows some important features that deserve attention:
(I) seems to be stronger than the residual soil to erosion and tends to provide protection to the ground below.
(Ii) the relatively low permeability compared to the rest of the ground below to form a perched water table at the base of a thunderstorm.
(Iii) the remains of earth, when the slope cut out the presence of relict joints can affect slope stability. But the base layer of colluvium is also a location map of potential error.
Dykes and decomposed dolerite slope stability?
Decomposed dolerite dikes are rich in clay show a high plasticity. In addition, the material is generally low permeability of the decomposed granite, which has many sides.
The presence of dolerite dykes degrades the direction parallel to the surface of the slope after slope failure can cause intense and prolonged rains. Shortages due to the permeability of the decomposed dolerite dykes, to sit in groundwater could be developed for the dams, and this is substantially more positive pore water pressure, which reduces the shear strength of soil.
The presence of dolerite dikes broken in a direction perpendicular to the surface of the slope can also cause a break in the slope after the storm. The low permeability of the materials tend to act as the construction of dams on the level of local groundwater for water coming down from the upper slopes. The increase in water level behind the "prey" leads to increased water pressure of the pores to reduce the resistance of the soil on slopes, leading to later failure.
What are the effects of pile groups, the stability of a slope?
Soil moisture on the slopes of Hong Kong usually consists of colluvium and rock weathering on fresh. Groundwater flow of the sloping terrain, and can participate in the race and the flow of water main. As the permeability of the soil tends to decrease with depth, the flow of groundwater can occur above the water table, which includes a tour of the lower surface of the water.
The presence of a lot of teams below the water table to prevent the flow of groundwater, which increases the level of groundwater. Significant developments in the slopes with a lot of influence has its roots in a sort groundwater is cut off. Growth of the lower surface of the water due to the effects of dam groups reduce the pile of slope stability, reducing the shear strength of the soil and eventually lead to failures slope.
Rising groundwater levels tend to increase with the angle of the slope and
depth of the groundwater flow.
How can you fill in the geogrid reinforcement?
Geogrid can fill the other side of the grid to meet the key to the other side of the grid. This is why it is different than the capacity of interlocking strips of soil reinforcement. Placing on both sides of the fill could be obtained from the condensation and the static load over the filling.
To trigger intersect the plane of the geogrid, the work must be done to expand the ground and defeat the forces of friction.
Colluvium shows some important features that deserve attention:
(I) seems to be stronger than the residual soil to erosion and tends to provide protection to the ground below.
(Ii) the relatively low permeability compared to the rest of the ground below to form a perched water table at the base of a thunderstorm.
(Iii) the remains of earth, when the slope cut out the presence of relict joints can affect slope stability. But the base layer of colluvium is also a location map of potential error.
Dykes and decomposed dolerite slope stability?
Decomposed dolerite dikes are rich in clay show a high plasticity. In addition, the material is generally low permeability of the decomposed granite, which has many sides.
The presence of dolerite dykes degrades the direction parallel to the surface of the slope after slope failure can cause intense and prolonged rains. Shortages due to the permeability of the decomposed dolerite dykes, to sit in groundwater could be developed for the dams, and this is substantially more positive pore water pressure, which reduces the shear strength of soil.
The presence of dolerite dikes broken in a direction perpendicular to the surface of the slope can also cause a break in the slope after the storm. The low permeability of the materials tend to act as the construction of dams on the level of local groundwater for water coming down from the upper slopes. The increase in water level behind the "prey" leads to increased water pressure of the pores to reduce the resistance of the soil on slopes, leading to later failure.
What are the effects of pile groups, the stability of a slope?
Soil moisture on the slopes of Hong Kong usually consists of colluvium and rock weathering on fresh. Groundwater flow of the sloping terrain, and can participate in the race and the flow of water main. As the permeability of the soil tends to decrease with depth, the flow of groundwater can occur above the water table, which includes a tour of the lower surface of the water.
The presence of a lot of teams below the water table to prevent the flow of groundwater, which increases the level of groundwater. Significant developments in the slopes with a lot of influence has its roots in a sort groundwater is cut off. Growth of the lower surface of the water due to the effects of dam groups reduce the pile of slope stability, reducing the shear strength of the soil and eventually lead to failures slope.
Rising groundwater levels tend to increase with the angle of the slope and
depth of the groundwater flow.
How can you fill in the geogrid reinforcement?
Geogrid can fill the other side of the grid to meet the key to the other side of the grid. This is why it is different than the capacity of interlocking strips of soil reinforcement. Placing on both sides of the fill could be obtained from the condensation and the static load over the filling.
To trigger intersect the plane of the geogrid, the work must be done to expand the ground and defeat the forces of friction.
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