Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths...
-
Upload
luis-pullas -
Category
Documents
-
view
62 -
download
4
Transcript of Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths...
![Page 1: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/1.jpg)
Gas Speak Colloquium 2011
Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines
Daniel TianMechanical Engineer
KBR
![Page 2: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/2.jpg)
Introduction
• What is Pipe Soil Interaction?• What is Pipe-Soil Interaction?– Behavior of buried pipeline in the surrounding soil– Pipe and soil together form the engineered systemPipe and soil together form the engineered system
• Soil Restraint Propertiesp– Relationship between soil resistance and pipe movement
• Virtual Anchor Length– Pipe section moving relative to the soil near directional change
![Page 3: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/3.jpg)
Why now?
• Risk based pipeline design approach (AS2885)
• Challenges facing pipeline designin Australia– Higher pressures– Larger diameters
Telfer Brooklyn-Lara Iona-Orford QueenslandTelferPipeline
Brooklyn LaraPipeline
Iona OrfordPipeline
QueenslandCSG Pipeline
Size (DN) 250 500 450 1050
Length (km) 443 65 101 Over 1000g ( )
MAOP (MPag) 10.2 10.2 15.3 10.2 / 15.3
WT (mm) 4.7 7.9 9.1 14.1 / 18.7
Material API 5L X60 API 5L X70 API 5L X70 API 5L X70Material API 5L X60 API 5L X70 API 5L X70 API 5L X70
![Page 4: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/4.jpg)
Onshore Pipeline Uplift, Uzbekistan
![Page 5: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/5.jpg)
Subsea Oil Pipeline Failure, Brazil, 2000
![Page 6: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/6.jpg)
Purpose of Calculating Pipe-Soil Interaction
• Soil restraint input into Pipe Stress Analysis (AutoPipe or Caesar II)• Virtual anchor length to define model boundary• Virtual anchor length to define model boundary
– Above-Ground Facilities - Buried Pipeline Sectionsp
(soil restraint is the fundamental part)
Compressor Station Major Water CrossingCompressor Station Major Water Crossing
![Page 7: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/7.jpg)
Determination of Soil Restraint Properties
Longitudinal TransverseActual
Vertical Upward Vertical Downward
Elastic-Plastic Soil Springp g
![Page 8: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/8.jpg)
Determination of Soil Restraint Properties
Soil and Pipe Properties:• Unit Weight ()
Elastic-Plastic Soil Springs:• Soil Stiffness (K1)
• Undrained Shear Strength (Su)• Angle of Internal Friction ()• Pipe Diameter (D)
• Ultimate Soil Resistance (P1)
ALAPipe Diameter (D)• Depth of Cover (H)
ALA
AutoPipe
Peng
![Page 9: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/9.jpg)
ALA Method for Calculating Pipe-Soil Interaction
• Widely recognised and applied
• Advanced soil modeller in Caesar II
• Based on laboratory and field i t l i ti tiexperimental investigations
• Formulas available for design factors• Formulas available for design factors
• Limitation:Limitation:– Under-estimate vertical upward
resistance (Appendix B)(Appendix B)
![Page 10: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/10.jpg)
AutoPipe Method for Calculating Pipe-Soil Interaction
• Detailed in AutoPipe Technical Reference Manual
• Based on laboratory and field i l i i iexperimental investigations
Li it ti• Limitations:– Design factors need to be
determined from tables and charts
(Pipe-Soil Appendix)
![Page 11: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/11.jpg)
Peng’s Method for Calculating Pipe-Soil Interaction
• First published in 1978
• Basic Soil Modeller in Caesar II
• Limitations:P li i ti ti– Preliminary estimation
– Based on theoretical soil mechanics
(Chapter 10)
![Page 12: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/12.jpg)
KBR Pipe-Soil Interaction Calculation Sheet
• Each of the 3 established methods• Each of the 3 established methods has strengths and weaknesses.
• Compare results from 3 methods and choose which method is suitableand choose which method is suitable for a particular application
• Calculate input data for stress software package
![Page 13: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/13.jpg)
Typical Soil Properties
Soil TypeSoftClay
NormalClay
StiffClay
LooseSand
MediumSand
DenseSandy y y
Dry Unit Weight(kg/m3)
1600 1800 2000 1600 1800 2000
UndrainedShear Strength
(kP )5 25 100 0 0 0
(kPa)Internal Friction
Angle (°)0 0 0 25 30 40
• To be used when soil data is not available for critical locations
Angle ( )
• Soft clay – worst design case for unknown soily g
![Page 14: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/14.jpg)
DN1000, 1.2m Cover, Soft Clay Condition, Various Methods
Vertical Upward
![Page 15: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/15.jpg)
DN1000, 1.2m Cover, Soft Clay Condition, Various Methods
Transverse
![Page 16: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/16.jpg)
DN1000, 1.2m Cover, Soft Clay Condition, Various Methods
Longitudinal VerticalDownward
![Page 17: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/17.jpg)
Calculation of Virtual Anchor Length in Buried Pipeline
• Distance from bend, tee or A/G-U/G transition to the point where pipe axial strain is completely suppressed by soil.
La
Virtual Anchor Length La = Co A [ε E + (0.5 - v) SHP] / Plong
Elastic Factor
Stress -Thermal
Expansion
Stress -Pressure
Elongation
LongitudinalSoil Resistance
Expansion Elongation
![Page 18: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/18.jpg)
Virtual Anchor Lengths under Different Soil Conditions
DN1000, 1200mm Cover, 55°C DT, 10.2MPag DP
![Page 19: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/19.jpg)
Applications
Anchor Block Requirementat Pig Trap
MajorW tWater
Crossing
Overbend atTop of Hill
Depth of Cover ChangeDepth of Cover Change
![Page 20: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/20.jpg)
Pipeline Design Engineer’s Responsibility
• Know how to use the right engineering design toolsengineering design tools
• Do some research and understand pipe-soilunderstand pipe-soil interaction
• Make sound engineering• Make sound engineering judgement
![Page 21: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/21.jpg)
Questions?
![Page 22: Daniel Tian - Determination of Soil Restraint Properties and Calculation of Virtual Anchor Lengths in Buried Pipelines (1).pdf](https://reader035.fdocuments.us/reader035/viewer/2022081722/55cf9e44550346d033b07a48/html5/thumbnails/22.jpg)
Disclaimer
These materials contain information of a general nature and are provided for discussion purposes only. They do not in any p p p y y yway represent engineering advice and KBR does not warrant the accuracy, completeness or currency of the information in these materials. Any person who uses or relies on these materials doesthese materials. Any person who uses or relies on these materials does so entirely at their own risk.