Problematic Soil and Ground Improvement Techniques PDF

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Report on Problematic Soil and Ground Improvement Techniques SUBMITTED TO: Engr. Ussama Waseem SUBMITTED BY: Abdul Moeez (13L-5779) Asad Abdullah (13L-5770) Aqib Rana (13L-5800) Afzaal Akram (13L- 5815) Hassan Khalil (13L-5792) DATE OF SUBMISSION: May 26, 2016 ORGANIZATION: FAST NUCES DEPARTMENT OF ...

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Problematic Soil and Ground Improvement Techniques Afzaal Jutt, Abdul Moeez Mahmood

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Report on

Problematic Soil and Ground Improvement Techniques SUBMITTED TO: Engr. Ussama Waseem

SUBMITTED BY: Abdul Moeez (13L-5779) Asad Abdullah (13L-5770) Aqib Rana (13L-5800) Afzaal Akram (13L- 5815) Hassan Khalil (13L-5792)

DATE OF SUBMISSION: May 26, 2016

ORGANIZATION:

FAST NUCES DEPARTMENT OF CIVIL ENGINEERING

Table of Contents ABSTRACT ................................................................................................................................................. 6 INTRODUCTION....................................................................................................................................... 7 SOIL:........................................................................................................................................................ 7 Importance of soil in construction ......................................................................................................... 7 PURPOSE .................................................................................................................................................... 7 EXPLANATION ......................................................................................................................................... 8 Problematic Soil: ..................................................................................................................................... 8 Types of problematic soil: .................................................................................................................. 8 Chemical soils:......................................................................................................................................... 8 

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Acidic Soil: ................................................................................................................................... 8 Saline soil ...................................................................................................................................... 9 Alkaline soil ................................................................................................................................ 10 Sodic Soil .................................................................................................................................... 11

Physical soils:......................................................................................................................................... 12 

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Dispersive soil ............................................................................................................................. 12

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Expansive (swelling) soil ............................................................................................................ 15

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Hardpan Soil ............................................................................................................................... 17

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Shock sensitive soil ..................................................................................................................... 18

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Collapsible soil............................................................................................................................ 14

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Sandy Soil ................................................................................................................................... 17

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Laterite Soils ............................................................................................................................... 18

Frost sensitive soil....................................................................................................................... 18

Ground Improvement Technique: ...................................................................................................... 19 Types of Ground improvement techniques..................................................................................... 20 Mechanism of Ground improvement techniques ........................................................................... 20 Mechanical techniques.......................................................................................................................... 20 o

Remove and replacement of soil ................................................................................................. 20

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Vibro flotation. ............................................................................................................................ 21

o

VIbro Reduction.......................................................................................................................... 22 2|Page

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Dynamic Compaction. ................................................................................................................ 24

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Compaction Piles ........................................................................................................................ 24

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Grouting ...................................................................................................................................... 25

o

Vacuum consolidation................................................................................................................. 27

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Rigid Inclusion ............................................................................................................................ 28

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Pre loading .................................................................................................................................. 29

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Vertical drains ............................................................................................................................. 29

o

Ground freezing .......................................................................................................................... 31

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Blasting ....................................................................................................................................... 31

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Wet soil mixing ........................................................................................................................... 32

Chemical techniques: ............................................................................................................................ 33 o

Addition of lime .......................................................................................................................... 33

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Addition of sulfates ..................................................................................................................... 34

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De-salinization: ........................................................................................................................... 34

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Addition of gypsum: ................................................................................................................... 35

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Addition of fly ash. ..................................................................................................................... 35

RESEARCH METHODOLOGY ............................................................................................................ 35 CONCLUSION AND RECOMENDATIONS ........................................................................................ 36 BIBLIOGRAPHY ..................................................................................................................................... 37

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List of Figures Figure 1a. Soil .............................................................................................................................................. 7 Figure 1b. Soil excavation ............................................................................................................................ 7 Figure 2 Acidic soil ..................................................................................................................................... 9 Figure 3. pH scale for soil in Geotechnical field.[1] ..................................................................................... 9 Figure 4. Saline soil .................................................................................................................................... 10 Figure 5 Sodic soil dry texture .................................................................................................................... 12 Figure 6. Sodic soil with cracks .................................................................................................................. 12 Figure 7. Sink hole ..................................................................................................................................... 13 Figure 8.Soil layer dispersion and cracking ................................................................................................ 13 Figure 9. Collapsing soil under the road ..................................................................................................... 14 Figure 10. Cracks on the soil due to expansion ......................................................................................... 16 Figure 11. Expansion cracks on soil ........................................................................................................... 16 Figure 12. Sandy soil ................................................................................................................................. 17 Figure 13 . Texture of sandy soil ................................................................................................................ 17 Figure 14. Hard pan soil layer ..................................................................................................................... 17 Figure 15. Laterite soil ................................................................................................................................ 18 Figure 16. Cracks on pavement due to frost heaving .................................................................................. 19 Figure 17. Soil removal ............................................................................................................................ 21 Figure 18. Soil replacement ........................................................................................................................ 21 Figure 19. Mechanism of vibro-flotation .................................................................................................... 22 Figure 20. Vibro Flotation ........................................................................................................................ 22 Figure 21.Vibrating probe ........................................................................................................................... 22 Figure 22. Steps for Top feed vibro- reduction ........................................................................................... 23 Figure 23. Step for bottom feed vibro- reduction ....................................................................................... 23 Figure 24. A crane doing dynamic compaction .......................................................................................... 24 Figure 25. Steps for compaction pile installation ....................................................................................... 25 Figure 26. Displacement pressure grout ..................................................................................................... 26 Figure 27. Displacement soil fracture grouting........................................................................................... 26 Figure 28. Rock fissure grouting................................................................................................................. 26 Figure 29. Vacuum consolidation ............................................................................................................... 27 Figure 30. Rigid inclusions ......................................................................................................................... 28 Figure 31.Pre loading diagram .................................................................................................................... 29 Figure 32. PVD Core .................................................................................................................................. 30 Figure 33.Compairison between soil with and without drainage paths ...................................................... 30 Figure 34. Ground freezing ....................................................................................................................... 31 Figure 35. Ground freezing ......................................................................................................................... 31 Figure 36. Wet soil mixing ......................................................................................................................... 32 Figure 37. Drainage path for De salinization .............................................................................................. 34

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List of Tables Table 1. Percentage of collapsing and its intensity ..................................................................................... 16 Table 2. Amount of Agricultural lime depending upon pH and soil texture .............................................. 33 Table 3. Improvement techniques for problematic soils ............................................................................. 36

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ABSTRACT The soil is an essential and second most abundant component of earth. Most of the world activities are directly or indirectly related to land. The soil is helpful to humans in many ways such as natural water filtration system, absorbing minerals, constructing shelter/homes and roads, and providing food through agriculture. In this paper, the reader is being educated with soil having physical and chemical problems in nature and their types such as changes in pH value and water moisture. The possible remedies of all the problems are under consideration and improvement techniques that are being used in the world to make the soil more suitable and stable to use for the purpose of farming, agriculture, and construction. The ground improvement techniques are used to improve unfavorable conditions of soil to favorable conditions. The adverse conditions of soil are collapsing, salinity, sodicity, sandy soil, hardpan, sandy soil, etc.

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INTRODUCTION SOIL: The soil is a mixture of materials such as organic compounds, water particles, very small rocks, microorganisms and decomposed dead matter. The combination of all of this makes the soil altogether. The soil is covering the top layer of the earth. It is normally brown in color and in providing a base for plantation and also a bed for the foundation of different building structures. The soil is a porous structure and can allow water to pass freely through it. This passage due to porosity is the reason how plant’s root get their water from the soil. Soil can be consolidated as well to remove all the air pockets from the soil. This compaction can be primary consolidation or secondary consolidation. There is a different category of soils, depending upon the size such as silt, clay, etc. Silt and clays have the finest particles. The soil is transported from one place to the other through many natural transportation methods, like with rain, it mixes with water and flows with it, and water takes the soil to different places and thus it is transported, and this soil will settle there as the water evaporates leaving the soil behind. The second method is a storm, the wind, and high-pressure air. The air will take the soil particles and transport this soil to different places. Other reason of soil transportation can be the work of gravity where the soil particles can move from high altitude areas to low altitude areas.

Importance of soil in construction Soil provide a base for the foundation of every construction on earth. So the properties of soil are very much important for the construction point of view. Because whole building can collapse just because of the soil. The soil can withstand the load of the building without any failure, but it can fail if the analysis of the soil, in which the foundation is being placed, is not properly done.

Figure 1a. Soil

Figure 1b. Soil excavation

PURPOSE The purpose of this research paper is to identify all the problems that can occur in a soil, physically or chemically and to provide a solution to those problems to improve that problematic soil for construction and another dynamic usage.

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EXPLANATION Problematic Soil: Sometimes, due to some unforeseen reasons, the soil starts to expand or swell or can have unexpected of the settlement, or can collapse. Due to some reasons, the structure of soil fabric can also change thus altering the strength of soil. All of these can create a lot of problem for construction point of view. The soil cannot be used for construction purposes and thus need some improvement techniques. Such soils are known as problematic soils.

Types of problematic soil: There are two types of problematic soils, chemical soils, and physical soils. 

CHEMICAL SOILS When the problem in the soil is due to the excess chemical amount, then it is known as chemical soil. There are following types of chemical soils. o Acidic Soil o Saline Soil o Alkaline soil o Sodic Soil

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PHYSICAL SOILS When the problem in the soil is due to the physical properties of soil. Then this type of problematic soil is known as Physical soil. Following are the types of physical problematic soil. o Dispersive soils o Collapsible soils o Expansive ( swelling) soils o Laterite soil o Sandy soils o Hardpan soil o Shock sensitive soil o Frost sensitive soil

Chemical soils: 

Acidic Soil:

Acidity is a property measured by the amount of hydronium ions present in the solution. More hydronium ions mean more acidic and fewer hydronium ions mean less acidic or alkaline. Acidity is measured on a pH scale. This scale ranges from 1-14 pH value; one means super acidic; pH value 7 means neutral and pH value 14 means super alkaline. Now if the pH of something is less than seven, then it is acidic, and if it is more than seven, then it is basic or alkaline. In the case of soil, the soil becomes acidic if its pH value is less than 7. Soil should have pH above 5.5 for the top layer and above 5 for sub-layer. 8|Page

Effect: Acidic soil is not recommended for construction point of view because if the soil is more acidic, it can cause corrosion to different building construction parts that are in contact with the soil. These construction parts are mostly cast iron, steel, etc. Mostly neutral soil is recommended for construction purposes because any change in pH can further affect the construction workability and usage of the soil. Also Shrinkage limit, plastic limit and liquid limit increase if the soil is more acidic. Causes Soil become acidic due to a certain number of factors.  Dec...