All the structures ultimately rest on the soil. If the soil deforms below the structure then the structure is directly affected by it. The kind of deformation, depends on the soil and the type of loading on it. It is important to study the deformation of the soil so that we can design the structure for its safety.
Deformation of soil: Any change in the volume of the soil, any vertical or lateral movement of the soil is deformation of the soil.
Necessity or importance of studying the deformation of soil:
(1)All structures rest on the soil so their safety depends on the type of soil. It is important to study the soil below.
(2) The deformation of the soil depends on the type of loading and the type of soil below, so it is important to keep the balance between the two.
(3) It is important to find out the deformation of the soil for the given loading, to design it within the allowable limits of the deformation.
Types of deformation:
(a) Swelling: Swelling is the property of the soil, by virtue of which it expands in volume after the addition of the moisture. This property is found specifically in the clay carrying the mineral named Montmorillonite. It has the tendency to catch the water in between its layers, which increases its volume.
(b) Creep : Creep is the slow movement of the soil generally under the action of its self load. Creep is affected by the soil properties like its shear strength, permeability and density etc.
(c)Heaving: Heaving takes place whenever their is the variation in the moisture content from place to another in the given bed of soil. Due to variation in moisture, the soil will have different volume at different places of the same bed of soil. The volume change may be either due to swelling or due to the freezing of the moisture in the soil pores of that area. It results in the upheaval of the soil of that particular area.
(d) Lateral movement: Lateral movement of the soil takes place generally in the slopes. The retaining walls are provided at such places, and the stability of these retaining walls depends upon the amount of the lateral movement of these soils, which again depends upon the type of soil, its moisture content and permeability etc.
(e)Freeze and Thaw: In the places where temperature goes below freezing temperature, when the water enters into the pores of the soil or the cracks of the soil, it freezes at the times of these low temperatures. As the ice has the larger volume, the cracks widens up, and results in the wider pores or cracks after the thawing of the ice into water. So next time, there is more space for the water to capture when the water enters in, and after freezing again, it will enlarge the given pores or cracks. So it is continuous process, in which the pores or the cracks are continuously widened. It is important to check this process.
Deformation of soil: Any change in the volume of the soil, any vertical or lateral movement of the soil is deformation of the soil.
Necessity or importance of studying the deformation of soil:
(1)All structures rest on the soil so their safety depends on the type of soil. It is important to study the soil below.
(2) The deformation of the soil depends on the type of loading and the type of soil below, so it is important to keep the balance between the two.
(3) It is important to find out the deformation of the soil for the given loading, to design it within the allowable limits of the deformation.
Types of deformation:
(a) Swelling: Swelling is the property of the soil, by virtue of which it expands in volume after the addition of the moisture. This property is found specifically in the clay carrying the mineral named Montmorillonite. It has the tendency to catch the water in between its layers, which increases its volume.
(b) Creep : Creep is the slow movement of the soil generally under the action of its self load. Creep is affected by the soil properties like its shear strength, permeability and density etc.
(c)Heaving: Heaving takes place whenever their is the variation in the moisture content from place to another in the given bed of soil. Due to variation in moisture, the soil will have different volume at different places of the same bed of soil. The volume change may be either due to swelling or due to the freezing of the moisture in the soil pores of that area. It results in the upheaval of the soil of that particular area.
(d) Lateral movement: Lateral movement of the soil takes place generally in the slopes. The retaining walls are provided at such places, and the stability of these retaining walls depends upon the amount of the lateral movement of these soils, which again depends upon the type of soil, its moisture content and permeability etc.
(e)Freeze and Thaw: In the places where temperature goes below freezing temperature, when the water enters into the pores of the soil or the cracks of the soil, it freezes at the times of these low temperatures. As the ice has the larger volume, the cracks widens up, and results in the wider pores or cracks after the thawing of the ice into water. So next time, there is more space for the water to capture when the water enters in, and after freezing again, it will enlarge the given pores or cracks. So it is continuous process, in which the pores or the cracks are continuously widened. It is important to check this process.
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