Download - Micro Pile
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
Micropilesan Introduction
GeoProfound Engineering Sdn Bhd
Micropiles - Timeline1952 - First introduced in Italy for foundation restoration (underpinning) of WWII damaged buildings1960�s � Widely used in Europe for underpinning old sensitive structuresmid 70�s � First introduced in USA (New York & Boston)1980�s � Being introduced in East AsiaToday � �Micro-mini Revolution� worldwide
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
Micropile Applications
Rock Socketting � where driven piles cannot penetrate.Supporting New Loads in Congested Areas Seismic Retrofit Arresting Structural Settlement Resisting Uplift/Dynamic Loads Underpinning Excavation Support in Confined Areas
Different Types of Micropiles
Flexibility � Suits the soil, Suits your needs�
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
Benefits of Micropiles
When you have problems of low headroom and restricted access�
No.1 Reason
Benefits of Micropiles
No.2 Reason :High Performance�Loading fr 3 � 500 tons!
�Higher As/Ac compared to RC Driven pile
As Micropile 4-8% vs As RC Pile <3%
-> Better in Bending, Lateral Loading
Shear resistance, Seismic performance
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
Benefits of Micropiles
High
As/Ac
Good for
High Lateral/Seismic Loading
Benefits of Micropiles
No.3 Reason :Can Penetrate Anything� Drilling thru stiff clay, sandstone, timber, granite (except buried steel). �Easier penetration in rock compared to bored pile.
By various creative ways of drilling�
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
Benefits of Micropiles Can penetrate
anything�
Wash Boring � Roller (Tricone) Bit
Auger
Down Hole HammerBuried Steel
Use Down-Hole-Hammer with Air Compressor to drill thru Rock/Granite
Benefits of Micropiles
No.4 Reason :
Flexibility
(Many Ways) to adjust to difficult soils�� Enhance End Bearing
��Cross-Breed� with other Ground Improvement technique�
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
Typical Pile Loading Capacity (Geotech+Structural)
Depending on soil & pile structure, some typical working loads :Dia 250mm, Rebar 6T25, 5m socket in Granite rock - (70+ tons)Dia 250mm, API Pipe As/Ac=8%, 40m in soft soils - (100 tons)Dia 150mm, Rebar 3T25, 20m thru soft clay + hard sandy silt end-bearing - (50 tons)
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
In SOIL (Typical Design using SPT Values)
Skin Friction, fs = 2N kN/m2
End Bearing, fb = 400N/3 or 10000 kN/m2
DESIGN PILE CAPACITY
DESIGN PILE CAPACITY
In ROCK (Socketing)
Skin Friction � Use extrapolation of SPT (e.g.Granite N=300-500, Sandstone N=200) fs = 2N kN/m2
Or use Rowe & Armitage (1987):
Skin Fric, fs=0.45 to 0.6(qu)0.5
Zhang & Einstein (1998):
End Bearing, fb = 3.0 to 6.6(qu)0.5
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
Structural Capacity of Piles
Typical Reinforcement = Rebar T16, 20, 25, 32
Ultimate Axial Load:fu = 0.4*fcu*Ac + 0.75*fy*As
Example : 6Y25 rebar in 250mm micropile, grout grade 30MPa, fy=500 N/mm2
fu = 1693kN = 169tons
CO$TRM$150�350 /meterPrice Depends on :
Reinforcement TypeRock Socketing ?Volume ( ) of holeGrouting Method (any post grouting)Location - AccessibilityLength/Quantity of piles
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
ProductionTypical ProductionWash Boring 250mm x 25m,Drag/roller bit, 4T25 cage, silty soil,3m casing 2 piles/day
-ditto- sandstone/granite socket 2m, DTH Hammer 2-3 piles/day
Typical Manpower Requirement
14 men3 piles/day/rig
TOTAL Production
2 @ grout mixer 1 @ agitator tank1 pump operator1 hoseman
Grouting etc
1 welder2 general workers
Fabrication
1x2 driller2x2 helpers
Rig (2 No.)
e.g. 100 micropiles, wash bore, 250mm, 20m, 2 rigs.
Can cut down to only 8-9 men for concurrent activity planning & utilising ready mix or slurry pump mixer, steel pipe & crane.
Production >4piles/day/rig
Overall cost reduction ~ 20-30% by increased production.
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
Typical Site Setup
Air Compressor
Water Tank
Grouting Plant
Fabrication Yard
Current Drilling Location
Preparing to grout pile here
Clearing of new area for setting out
Drilling Pump
Access R
d
Entrance/Delivery
Small Quantity � Small PilesFor small sites,use simpler rigs with lower torque, faster RPM�(depending on soil type)
e.g. SI rigs
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
Small/Constrained sites -SI Rig/ Portable Drill frame e.g. �Jacro� is the solution!
Big Quantity, Small machines�
Tmn Kotamas, Kota Tinggi, Johor
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
Small Quantity, Big machine�
JB Inner Ring Road
Johor Bahru
Big Quantity, Big machine�
Vibro unit�
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
Drilling ToolsDrilling Rig (Flexible) � Size, Rotary Torque, RPM, maneuverity
Drilling Type � Wash Bore, Dry Auger, DTH hammer (Rock Drill)
Drill Bit & Rods � Drag Bit, Roller Bit, DTH (flat/convex), Tubex.
Pump � Recirculating fluid � Diaphragm pump / Piston pump.
Jack-in- Micropile
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
Monitor drilling parameters :Thrust Force on Drilling bit Drilling Fluid Flow Rate & PressureRotary/top drive RPMRotary/top drive torqueAir Compressor Output PressureRecirculating Fluid Viscosity
Why?Thrust Force : The thrust force is the force acting along the axis of the drill during cutting. The thrust force plays a significant role in the buckling of the drill.
Torque/RPM : The Torque/RPM signifies the power needed by the machine tool to drill the hole. Also, Torque acting on the drill can result in torsional vibrations affecting hole quality.
500kV Transmission Line Micropiling Works
b4
T8 Line 2
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
500kV Transmission Line Micropiling Works
After
T8 Line 2
500kV Transmission Line Micropiling Works
T13 Line 2
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
500kV Transmission Line Micropiling Works
T8 Line 2
500kV Transmission Line Micropiling Works
T38 Line 1
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
500kV Transmission Line Micropiling Works
T38 Line 1
500kV Transmission Line Micropiling Works
UpliftLoadTest
Third Arm Engineering Sdn Bhd -Your Ground Improvement Solutions
Tel : 016-7236492, 07-2364932
Solutions for the Difficult Ground
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