Soil Nailing , Soil Nailing Technique, Types of soil nailing

Soil Nailing, Soil Nailing Technique, Types of Soil Nailing

 
 
Soil Nailing , Soil Nailing Technique, Types of soil nailing,
Soil Nailing
 
 
 

SOIL NAILING AND SOIL NAILING TECHNIQUE

 

INTRODUCTION OF SOIL NAILING➱

 
Soil
Nailing
Is a process To Make The soil or Soil fill  More Able to resist
loads (direct loads, Shear Loads Radial loads etc) Or to Make it more
stable,Soil nailing Reinforces soil hence the soil becomes more
stable,
 
Generally
Soil Nailing Technique is used in steep sloppy areas, high fill areas, High
embankment, retaining walls And other Structures where There is more chance of
failure of soil,
 
Here in
In this post we are going to describe about soil nailing process, soil nailing
technique, types of soil nailing and its applications,

How does a soil nail wall work?

SOIL NAILING PROCESS- TECHNIQUE➱


What is soil nailing technique?
In the
Process or Technique of Soil Nailing The Soil Is Reinforced With An Element
Such As Self Drilling Anchor bars or Reinforcing Bars Which Are
called Nails See in the fig. 
 
These Self
Drilling Anchor bars or Reinforcing Bars are installed into Self Drilled holes
or pre-drilled holes and after it grouted with contentious mix, 
 
These Self
Drilling Anchors or Reinforcing bars are installed at an angle of 5 to 20
degrees with vertical generally or any other angle which is specified,
 
As The
Drilling Work Proceeds,The concrete, Shotcrete or any other Drilling materials
are used on The drilled face to grout the nails, 
 
Soil Nailing , Soil Nailing Technique, Types of soil nailing,
Soil nailing Details
 
 

MACHINERY REQUIRED FOR SOIL NAILING➱

 
➤Grouting and mixing Equipments,
➮ High-speed shear Colloidal mixer, Grout pump, 
 
➤Drilling Equipment,
➮Rotary Air Flushed and water Flushed drilling machine, tricone bit , Rigid Drill Rods,
 
➤Compressor,
➤Shotcreting  Or Guniting Equipment,
 

MATERIALS REQUIRED FOR SOIL NAILING➱

 
➤Reinforcing Steel Rods Or Nails,
➤Self drilling anchor(SDA) bars,
Soil Nailing , Soil Nailing Technique, Types of soil nailing
Self Drilling Anchor
 
➤Shotcrete, Concrete or Any other grouting material,
➤Grout mix, 
 

ORIGIN
OF SOIL NAILING TECHNIQUE➱

 
➤The
soil nailing technique was first time implemented in France near Versailles for
a Railroad widening Project in 1972,
Soil Nailing , Soil Nailing Technique, Types of soil nailing
Soil nailing
 
➤The soil nailing Technique in United States was used first time for the support of a
13.7-metre deep foundation excavation in dense silty sand in 1976,
 

TYPES OF SOIL NAILING -METHODS➱


How do you install soil nails?

Following
Are the Various Types of Soil Nailing Methods or process,
Soil Nailing , Soil Nailing Technique, Types of soil nailing
Inserting nails and fixing plates soil nailing
Soil Nailing , Soil Nailing Technique, Types of soil nailing
Using Shotcrete and grouting
 
 

1-Grouted
Soil Nailing or Drilled Soil Nailing
 

 
➤In
This type of Soil Nailing and drilling is done on the Wall or the Slope Face
Where nailing is Required,
➤Then
The nails are inserted in the Drilled Holes,
➤After
it the Drilled hole is Filled with Cement Slurry, Shotcrete or any other
Grouting Material,
➤The
The diameter Of Nails Are Taken From 100 mm to 200 mm And the Spacing between each
nails Are Taken 1.5 meters,
Soil Nailing , Soil Nailing Technique, Types of soil nailing
Grouted soil nailing
 
 

2- Driven
Soil Nailing 

 
➤This
Type Of Soil Nailing Is used for temporary Stabilization of Slopes,
➤This
Soil Nailing Is Faster Than Other nailing methods,
➤In
In this Soil Nailing Method, The Reinforcement bars are inserted in the face of
slope While the Excavation Activity is Going On,
➤The
The diameter of Reinforcing bars is normally 19 mm to 25 mm, Which is Smaller in size
as Compared to Others,
➤The
Spacing between Nails is Provided 1 meter to 1.2 meter,
➤In The
Driven Soil Nailing There is no Protection of Nails from Corrosion And Rusting,
 
Soil Nailing , Soil Nailing Technique, Types of soil nailing
Driven soil nailing

3- Self
Drilling Soil Nailing

 
➤Self
Drilling Anchors (SDA) Bars or Hollow bars are used in self-drilling soil
nailing,
➤Bars
are inserted and Drilled into the surface, and at the same time Grout is
injected While the Drilling Process is going on,
➤In
Self Drilling Soil nailing The Self Drilling Anchors Or hollow Reinforcing Bars
Are More Protected From Corrosion and rusting as compared to Driven soil
nailing method,
➤This
is Faster Than Driven Soil Nailing,
 
Soil Nailing , Soil Nailing Technique, Types of soil nailing
Self drilling soil nailing

4-Jet
Grouted Soil Nailing

 
➤In
This Soil nailing method,The water jets Are used for eroding The Soil To make
holes in the surface,
➤After
it the Reinforcing Steel Bars Are inserted and fitted in the ready holes and
grouting is done with shotcrete, Concrete or Other Grouting materials,
➤In Jet
Grouted Soil Nailing The Reinforcing Steel bars are protected From corrosion
and rusting,
 
Soil Nailing , Soil Nailing Technique, Types of soil nailing
Jet grouted soil nailing

5-
Launched Soil Nailing

 
➤In
launched soil nailing, The Reinforcing steel bars are inserted Forcefully into
surface in a single shot with the help of of highly compressed air mechanism,
➤In
This Method The Installation process of nails is fast, But it is difficult to
control over length of bars penetrating the surface,
➤The
length of Reinforcing nails is around 6 meter and the diameter is 38 mm,
Soil Nailing , Soil Nailing Technique, Types of soil nailing
Launched soil nailing
 
 

APPLICATIONS
OF SOIL NAILING➱

 
➤Soil
nailing is used for the stabilization of Existing Retaining walls,
➤In
Excavating retaining structures in urban areas for high-rise buildings and
underground utilities,
➤In
Eradicating and Redemption of Landslide,
➤Stabilizing
the Roadways, Highways, and expressways embankments and steep slopes,
➤Retrofitting
and construction of abutments of bridges,
➤Steep
cutting stabilization,
➤Stabilization
of over steep existing embankments,
➤Providing
long-term stability to existing concrete structures without demolition and
rebuilding costs,
➤Temporary
excavation shoring,
➤Stabilization
of Railroad cut slopes,
➤For
Strengthening The Tunnel portals in steep and unstable slopes,
➤For
Stabilization of Slopes in hilly areas where roads are constructed, where
movement of vehicles, people or animals is more,
 
Soil Nailing , Soil Nailing Technique, Types of soil nailing
Soil nailing 

 

 

ASSUMPTIONS
AND CONSIDERATIONS IN INSTALLATION OF SOIL NAILS➱

 
➤Soil
Nailing Should be started within some limit of time after excavation, any delay
may lead to the collapse of soil slope,
➤Reinforcing
bars or soil nails must penetrate beyond the slip plane into the passive zone
for 4 meters to 5 meters,
➤Metallic
reinforcement soil nails get corroded,
➤The
The area occupied by Reinforcing soil nails is sterilized and the site posed
constraints to the development in future,
Soil Nailing , Soil Nailing Technique, Types of soil nailing
Soil nailing Anchor plates
What is a soil nail wall?
 

ADVANTAGES
OF SOIL NAILING➱


What are the advantages of soil nailing?

➤With
the help of soil nailing the erosion of soil of high fill, high embankment or
steep slope can be avoided,
➤After
soil nailing The age, durability and stability increase,
➤Soil
nailing is suitable for confined locations with difficult access As the
The equipment required for soil nailing is small and mobile to use,

 

➤The
failure of the soil nailing system is ductile that’s why it provides
warning signs before failure,

You must read About Asphalt Concrete And Bituminous Concrete Click Here
Click here for Engineering jobs and other updates

 

GRANULAR SUB BASE CONSTRUCTION – GSB CONSTRUCTION

GRANULAR SUB-BASE CONSTRUCTION – GSB CONSTRUCTION

GRANULAR SUB BASE CONSTRUCTION - GSB CONSTRUCTION
GSB Construction


GRANULAR SUB BASE CONSTRUCTION

FUNCTION:➱

             It Acts as a Drainage layer for The pavements to avoid excessive wetting and weakening of the subgrade.
 
             In Strength, it is superior as compared to the subgrade, various materials and techniques are used for the construction of the base course.
 
             It is an intermediate layer between the subgrade and granular base course.
 
What is a granular sub-base?
What is a granular sub-base in road construction?
 
        If The Thickness of the base layer provided in the design permits,
 
➤The sub-base layer shall have two sub-layers.⇩
➤Drainage layer and the filter layer.
➤The upper layer of the sub-base functions as a drainage layer to drain away the that enters through surface cracks.
➤The lower layer of the base should function as a filter/separation layer to prevent intrusion of sub grade soil into the pavements.
GRANULAR SUB BASE CONSTRUCTION - GSB CONSTRUCTION
permeability testing of GSB
 
        If the thickness of the granular sub-base layer is less than or equal to 200 mm.
➤Both drainage and filter layers can not be provided separately ( considering the minimum thickness requirements as per 7.2.2).
➤ For such cases, a single drainage-cum-filter layer with GSB gradation Ⅴ or Ⅵ of MoRTH specification may be provided.
 

MATERIALS REQUIREMENTS:⇨

➤Natural sand,
➤Crushed gravel,
➤Crushed stone,
➤Crushed slag,
➤Brick metal,kankar and crushed concrete is permitted in the lower sub-base,
➤Shall be free from organic or other deleterious constituents,
➤Shall satisfy the grading requirements as is explained below,
➤shall satisfy the physical requirements as it is explained below,
 
GRANULAR SUB BASE CONSTRUCTION - GSB CONSTRUCTION
materials required for GSB
GRANULAR SUB BASE CONSTRUCTION - GSB CONSTRUCTION
grading requirements
GRANULAR SUB BASE CONSTRUCTION - GSB CONSTRUCTION
physical requirements
Is code for a granular sub-base?
What is the Type 1 granular sub-base?
What is the granular subbase used for
What is a granular base course
What is the size of GSB
 

GRANULAR SUB BASE CONSTRUCTION OPERATION

TOE LINE FIXING:➩

➤The Toe line/fixing of pegs to mark the limits of the Granular sub-base shall be done before the commencement of work.
➤The width of pavements for the toe line shall be calculated by referring to the drawing with due consideration to formation width plus the offsets and slopes of different layers’ depth the current layer from the formation road level( FRL).
 
GRANULAR SUB BASE CONSTRUCTION - GSB CONSTRUCTION
grading and rolling of GSB
 

HAULING AND DUMPING:➯

➤The Required Quantity of GSB shall be Calculated and informed to the GSB Dumping Supervisor or Staff at the site,
➤Dumping Patterns Such as to ensure uniform Spread shall be determined and explained to the dumping supervisor or staff,
➤The materials for GSB shall be hauled to by tippers and dumped on the bed in a predetermined pattern,
 
GRANULAR SUB BASE CONSTRUCTION - GSB CONSTRUCTION
GSB Material Quantity Calculation
How is base course aggregate calculated
What is base course material
What is GSB material
 

GRANULAR SUB BASE CONSTRUCTION OPERATION 

SPREADING AND GRADING:➯

➤The materials shall be up to the required thickness,
➤Control pegs at every 10 meters along centre line shall be fixed on both sides of the bed in such a manner That they are not disturbed by the movements of the grader,
➤Required level shall be marked on the pegs with suitable vertical offsets,
➤After rough initial spreading, a cotton/nylon string line(line dori) shall be held at the marks on the control pegs on both sides,
➤ The height of String line from the bed top is measured at fixed horizontal offsets from the center line,
➤The grader operator shall be directed according to the measurement in the above step to cut and fill material at every point,
➤Each grader run shall overlap by at least 1/3rd of the bled length,
➤Most important if any suggestion is observed, instruct the operator to correct the same while grading,
 

WATERING:➱

➤The moisture content shall be checked for OMC and if it is less than required water may be added by sprinkling and if it is more than required, shall be allowed to dry by exposure to the sun,
➤The moisture content shall be adjusted with allowance for evaporation losses in a manner to achieve 1 % above to 2 % below OMC During compaction,
 

COMPACTING:➱

➤Before the commencement of compaction and while spreading the GSB all the oversize materials available more than 2/3rd the thickness of the layer shall be removed manually,
➤The compaction shall be done mechanically using vibratory rollers of 80 to 100 KN static weight for the entire width of the pavement,
➤The rolling shall commence from the lower edge and proceed towards the upper edge, each pass of the roller shall overlap 1/3rd of the proceeding pass,
➤During the compaction, any low spots shall be filled with the material of the same properties and high spots shall be excavated and removed manually,
➤ The number of passes shall be decided beforehand by conducting trial,
➤Each layer shall be tested by sand replacement  method,
 

RECTIFICATION:➱

➤If The surface is higher than the required level the defective area shall be trimmed off and compacted,
➤If the surface is lower than the required level the defective area shall be sacrificed, fresh material shall be placed and compacted,
 

BUMPING:➱

➤If The surface is exhibiting bumping then the material in the defective area shall be removed to full depth and fresh material will be placed and compacted,
 

SEGREGATION:➱

➤If segregation is observed then the material from the defective area shall be removed to full depth and either made good and replaced or replaced by fresh material,
 
GRANULAR SUB BASE CONSTRUCTION - GSB CONSTRUCTION
GSB Construction
 
 

QUALITY CONTROL TEST AND THEIR FREQUENCY

➤Gradation at a frequency of 1 test for every 200 cum,
➤Moisture content test as per IS 2720 Part-2 at a frequency of 1 test for every 250 cum at the time of spreading and rolling,
➤MDD and OMC  As per IS 2720 Part-8 at a frequency of 2 test per 3000 cum,
➤Laboratory determination of CBR as per IS 2720 Part-16 as required,
➤Atterberg’s limits at a frequency of 1 test per 200 cum,
➤Field Density test as per IS 2720 Part-28 at a frequency a set of test for every 1000 sqm to a minimum of 6 tests up to 3000 sqm, if nuclear density meter is used the frequency shall be doubled,
 

PROBLEMS AND REMEDIES IN GSB CONSTRUCTION

 
PROBLEMS REMEDIES 
➤ GSB bed compaction less than required

➤Variation in surface level

➤Over burden materials mixed during preparation of GSB material,

➤Approved GSB bed

➤GSB Material Dumped Over moist or Wet Surface

➤Required Compaction should not be less than 98 %,
poor Compaction may lead to settlement
➤surface level tolerance limits:➯
for Sub grade:- +/- 20 mm,
for GSB        :- +/- 10 mm,
The Surface level shall be maintained within the tolerance limits else may impact of required thickness of next layer,
Rework may occur due to unacceptable tolerance,
➤Gradation:➯ specified gradation as per approved design
Liquid limit and Plasticity Index:➯ Max 25 And max. 6,
In such case, specified gradation and plasticity index limit shall be ensured before loading the GSB materials or at least before spreading.
Chances of Impact on the drainage properties,
➤At actual completely disturbed bed due to the following reasons,
➯Poorly Graded ⟶ Leads To Segregation,
➯Poor Workmanship⟶after final grading it would have rectified,
➯Poor Quality Control⟶before testing it would have suggested to concerned site Engineer to rectify the bed which leads poor compaction and segregation,
100 % Rework Required
➤Moisture Content ⟶OMC +1% and OMC -2%
➱The bed Should Have moisture Content as per requirement before proceeding for the next layer,
➱Rework may occur due to improper supervision
➱settlement of successive layer
 
Click here for More Working Procedures and Engineering jobs