Liquification Grad project 2024 HUE Updated 0.2.pdf

Liquefaction occurs when saturated soil loses strength and behaves like a liquid during an earthquake or other ground-shaking events.
This transformation can significantly damage buildings and infrastructure, as the ground beneath them becomes unstable and loses its ability to support heavy loads.

1. Soil Liquefaction
Faculty Of Engineering
Course: foundation Grad project 2024
Under the supervision of :
Prof.Dr. Adel Deif
Dr. Ahmed Fawzy Dr. Ahmed Rabah Dr. OmniaEmara
Assistant teacher: Abd El Rahman El Masry
Done by:
Mohamed Ahmed Sherif ID: 1191069 Level 4
Mohamed Farag Mosa ID: 1191289 Level 4
Mostafa Abdo Elshahat ID:1181213 Level 4

2. Table of Contents:
1.Introduction
•The Definition of Liquefication and its Impact on Structures
•Causes of Soil Liquefaction
2.Historical Examples
•San Francisco Earthquake(1906)
•Niigata, Japan, June 16, 1964
•Alaska Earthquake, USA (1964)
•Christchurch Earthquakes of 2010–11
3.Liquefaction of Soil

3. Table of contents:
4. Liquefaction-Related Failures - Types of Failures
5. Factors Affecting Liquefaction Susceptibility
6.Problems
7. Strategy for Liquefaction Mitigation
8. Liquefaction Mitigation by Soil Improvement Techniques
9. Lessons Learned
10. Summary and Conclusion
11. References
.1

4. 1.Introduction

5. The Definition of Liquefication and its
Impact on Structures:
Liquefaction occurs when saturated soil loses strength and behaves
like a liquid during an earthquake or other ground-shaking events.
This transformation can significantly damage buildings and
infrastructure, as the ground beneath them becomes unstable and loses
its ability to support heavy loads.

6. Causes of Soil Liquefaction
1.Ground Shaking: The shaking during an earthquake rearranges sand and silt grains
in saturated soil underground, increasing pressure and causing grains to float.
2.Water Pressure: Water between the soil grains is squeezed as pressure builds up,
leading to the grains floating and water being forced to the surface through cracks.
3.Loose and Wet Soil: Soil must be loose, sandy, or silty and saturated below the water
table for liquefaction, with clay and gravel typically not liquefying.
4.Lateral Spreading: Liquefied soils can move laterally towards streams or rivers, or
downhill towards lower ground, leading to cracks in the ground surface as the soil
shifts underneath.

7. 2.Historical Examples

8. San Francisco Earthquake (1906)
Earthquake Details:
•Magnitude: 7.9 to 8.5 Richter
•Duration: Less than 1 minute
•Impact of Liquification: The earthquake caused liquefaction in areas like the
Marina District and Mission Bay, where saturated soils were present.
•House Damage: Approximately 28,000 buildings were destroyed by the
blaze.
•Infrastructure Damage: Over 500 blocks in the city center, covering around
4 square miles (10 square km), were leveled due to the inferno.
Consequences:
*Buildings and infrastructure built on these unstable soils suffered significant
damage.
* Widespread destruction and loss of life resulted.

9. Niigata, Japan (Earthquake),June 16, 1964
Earthquake Details:
• Magnitude: 7.5 Richter
•Duration: Unknown
•Impact of Liquefaction: The Niigata earthquake resulted in widespread liquefaction that caused
severe damage throughout Niigata, Japan.
•House Damage: Over 3,500 houses were destroyed, and 11,000 were damaged due to soil
liquefaction and lateral spreading.
•Infrastructure Damage: The collapse of the Showa Bridge was a notable consequence of the
earthquake, with its failure attributed to the vibration between the bridge and liquefied ground
motions.
Extra information:
•The 1964 Niigata earthquake and the 1964 Alaska earthquake highlighted liquefaction phenomena.
•Engineers and seismologists paid attention to the devastating effects of liquefaction after these
earthquakes.

10. Alaska Earthquake, USA (1964)
Earthquake Details:
•Magnitude: 9.2 Richter
•Duration: 3 minutes. (It was the second-largest earthquake ever recorded)
•Impact of Liquefaction: Ground failures are an effect of seismic activity in which the ground
becomes very soft and acts like a liquid, causing landslides, spreading, and settling.
•House Damage: Approximately 30 blocks of homes and businesses were damaged or
destroyed.
•Infrastructure Damage: Water mains, gas lines, sewers, telephone, and electrical systems
were all damaged or destroyed due to the landslides.
•A tsunami followed the earthquake, causing further damage and deaths in Crescent City, California.

11. Christchurch Earthquakes of 2010–11
Earthquake Details:
•Magnitude: Started at 7.1 Richter in 2010 then struck again in 2011 with a magnitude
of 6.3 Richter.
•Duration: Started on 4/9/2010 then struck again on 22/2/ 2011, 13/6/2011, and finally
23/12/2011
•Impact of liquefaction: The earthquakes caused widespread liquefaction in many
villages due to the city's foundation on soft soils.
•House Damage: 10,000 homes needed to be rebuilt and 3,500 demolished.
•Infrastructure damage: Multiple buildings collapsed, and burst water mains,
flooding, liquefaction, and power outages impacted the city.

12. Liquification in saturated soils is a
phenomenon that can have severe
consequences for infrastructure and
human safety
One of the primary causes of
liquefaction is seismic activity
Another factor that contributes to
liquefaction is the presence of
loose, cohesionless soil
Another preventative measure
is the implementation of proper
foundation design
To prevent liquefaction, various
engineering techniques can be employed
Case studies provide valuable
insights into the effects of
liquefaction and the success
of prevention measures
In conclusion, understanding liquefaction
in saturated soils is crucial for
safeguarding infrastructure and
protecting human lives
Source:
https://fastercapit
al.com/topics/und
erstanding-
liquefaction-in-
saturated-
soils.html

13. 3.Liquefaction of Soil:
1.Reduction of shear strength due to pore pressure buildup in
the soil skeleton during an earthquake.
2. Liquefaction-when the strength and stiffness of a soil is
reduced due to earthquake shaking
3.Liquefaction occurs in saturated loose to medium sand
https://www.linkedin.com/pulse/basics-soil-
liquefaction-1-vipin-tyagi/

14. 4.Liquefaction-Related
Failures

15. Types of Failures in Liquefaction:
Four basic types of ground failure commonly result from liquefaction:
1.Flow failure
2.Lateral spread
3.Ground oscillation and Loss of bearing capacity.
4.Other failures associated with liquefaction include the rise of pore water pressure, sand boils, and
various types of deformation.

16. Flow Failure
Occurs on steep slopes (>3 degrees) with loose or contractive sediment in shear deformation zones.
Source:
Wang, S., Idinger, G. &
Wu, W. Centrifuge
modeling of rainfall-
induced slope failure in
variably saturated soil.
Acta Geotech. 16,
2899–2916 (2021).
https://doi.org/10.100
7/s11440-021-01169-x

17. Lateral Spreading
•Lateral spreads develop beneath gentle slopes (0.3 to 3
degrees) or near free faces like river channels.
•Lateral spread requires the liquefiable layer to be
continuous over a significant distance relative to its
thickness.

19. 5.Factors Affecting Liquefaction
Susceptibility

20. Factors Affecting Liquefaction Susceptibility
1- Grain-size distribution and
soil types including:
• grain size curve
2- Relative Density Dr
•Low relative density leads to soil
liquefaction

21. 3- Earthquake Loading Characteristics

22. 4- Vertical Effective Stress and
Over-consolidation
• Increase the vertical effective stress
decreasing the liquefaction
5- Age and Origin of the Soils
•The recently deposited liquefied rapidly

23. 6- Seismic Strain History
•When the soil is subjected to another earthquake it can be easy to liquefy compared with other
soil subject to the first earthquake
7- Degrees of Saturation
•Liquefaction increased with the increase of the degree of saturation

24. 6.Problems:

25. To achieve the soil is liquefied or not
at a given depth
CSR=

seismic

−
vo
=0.65
a
max

vo

r
gvo
d
−

Cyclicstressration
CSR

26. where
seismicis theshearstressoftheappliedearthquake,
a
maxisthemaximumpeakhorizontalacceleration,
relatedtoearthquake magnitude (M). It can be taken fromthe
time accelerationchart recordedduringthe earthquake,it was
found(0.1g or given)at M=7.4.

vo
istheaccelerationdue togravity.
is thetotal overburdenpressureat the depth(Z)oftheconsideredpoint,

-
vois theeffectiveoverburdenpressureatthedepth(Z)of the
consideredpoint,
rd is the stress reduction factor for any point at depth (Z),
rd=1-0.01Z.
g

27. NSPTnumberat
studieddepth
corrected
(N)=N
160
100

−
vo
(N
1)
60eff=(N
1)
60+(N1)
60
(N
1)
60eff
Effectivestandardpenetrationresistanceor Equivalent clean sand
penetration resistance
(N
1)
60 Correctionfor siltcontent
(N
1)
60
ObservedcorrectedSPTvaluefor thesilty
sand fromthe equation.
FINES CONTENT (%)∆ (N 1)60
10 1
25 2
50 4
75 5Factorof safetyagainstliquefaction
FL=CRR/CSR FL>1 Noliquefaction

28. CRRfrom curve FL=CRR/CSR
Noliquefaction
FL>1
FL<1liquefactionoccurs unsafe
Relationship between Stress Ratio
Causing Liquefaction and (N
1)
60 values
for Silty Sand for M = 7.5 (after Seed et
al. 1985)

29. •Avoid Liquefaction Susceptible Soils
•Structural Design
•Soil Improvement
7.Strategy for Liquefaction Mitigation

30. Avoid Liquefaction Susceptible Soils
•Thefirstpossibilityistoavoidconstructiononliquefaction susceptiblesoils.
•Pre-investigationof thesitesoilcriteria

31. STRUCTURAL DESIGN
To maintain stability by
reinforcing the
foundation
To relieve the external
Forces By softening or
modifying the structure
Build Liquefaction
Resistant Structures
Examples:
1.Additionalductility.
2.Adjustablesupport.
3.Usepilefoundation/Caissons.
Skirted system
4.Modifytheshapeofthe
foundation.
5.Usea tie-independentfoundation
together.
Example:
•Adjustment of bulk
unitweightofburied
structure

32. SOIL IMPROVEMENT
To improve the soil so that the soil will
not collapse under earthquake loading
To increase the liquefaction
strength of the soil
To reduce the earthquake-
induced shear stress ratio
To achieve rapid
dissipation of excess
pore water pressure
•Examples:
•Drain
•Replacement
•Granularcolumn
•Blasting
Example:
1.Soilreinforcement
2.Insitedensification
3.Grouting/solidification
Examples:
Tolower theundergroundwaterlevelto
reduce the shear stress and increase the
verticaleffective stressbelowtheGL
Themosteffective
strategy
Soil
remediation
technique

33. Soil reinforcement
In-site densification
technique
Grouting/ Solidification
Cementation
Drainage
8.Liquefaction Mitigation by Soil Improvement
Techniques
To increase the dissipation of
the excess pore water pressure

34. LiquefactionMitigationUseing Soil
RenforcementTechnique
•CommonlytypesusedinLiqu.Mitig.
•Micro-piles,orRootpiles
•Soilnailing,
•Granularcolumnsand
• Groundanchors
•Fiberreinforcement,geosynthetics,
•Lateralconfinementtechnique
•Skirtedfoundation

35. Liquefaction Mitigation Using Granular
Column/Drained Improvement
The defect of using micro-piles
leads to the use of an alternative
approach of soil reinforcement to
mitigate the liquefaction.
Granular
column
First usage by
Seed and Booker,
(1977).
Technical
Feasibility
Low Energy
Coast
Effectiveness
1- Reinforcement
2- densification
3- Drainage Path

36. Densification Technique
•Toreduce theliquefactionpotential
•Densification produces a permanent volume change and decreases the tendency to generate the
positive excess pore water pressure compared with loose cases.
•Densification methods
•Dynamic compaction
•Vibroflotation
•Vibro – rod
•Blasting
•Compaction grouting
To avoid a large
increase in PWP

37. LiquefactionMitigation Technique Using
Solidification/Grouting
•Last mentioned methods can not be used under existing building:
•So there are alternative procedures were used to mitigate the liquefaction
under the existing building. Urban area, small area. Solidification prevents
soil subsidence and gives it a high cohesive force.
•Injection

38. 9.Lessons Learned:
•The Christchurch earthquakes emphasized the importance of:
•Site-specific investigations to assess liquefaction risk.
•Engineering design considerations to mitigate liquefaction effects.
•Ongoing monitoring to manage potential liquefaction hazards.
•The event highlighted the destructive power of liquefaction.
•It spurred advancements in understanding liquefaction and developing engineering
techniques to mitigate its effects

39. 10.Summary and Conclusion
•Liquefaction occurs when saturated soil turns into a liquid-like state during earthquakes,
weakening the ground and causing damage to buildings and infrastructure.
•Historical examples of destructive liquefaction events include the 1906 San Francisco, 1964
Niigata, 1964 Alaska, and 2010-2011 Christchurch earthquakes.
•Factors affecting liquefaction risk include grain size and type of soil, soil density, earthquake
strength, soil depth, soil age, and water content.
• Mitigation strategies involve avoiding building on susceptible soils, designing structures to resist
liquefaction forces, and improving soil stability to reduce the risk of liquefaction.
•In conclusion, liquefaction is a serious hazard that can cause significant damage, and
understanding its causes and factors is crucial for prevention. Mitigation strategies are essential
for protecting lives and property.

40. 11.References:
•https://fastercapital.com/content/Liquefaction-induced-Building-Damage--Lessons-from-Past-Disasters.html#Understanding-Liquefaction-induced-Building-
Damage
•https://www.britannica.com/event/San-Francisco-earthquake-of-1906
•https://www.geoengineer.org/education/web-class-projects/ce-179-geosystems-engineering-design/assignments/liquefaction-1964-niigata-earthquake
•https://www.scribd.com/document/379321130/Niigata-Earthquake
•https://ds.iris.edu/aed2/c/newmadrid/popups/earthquakes/Earthquakes_5_niigata.html?KeepThis=true&TB_iframe=true&height=575&width=900
•https://rctwg.humboldt.edu/1964-great-alaska-earthquake-tsunami
•https://depts.washington.edu/liquefy/html/quakes/alaska/alaska.html#:~:text=Alaska%20earthquake%2C%201964&text=and%20in%20sand%20and%20silt,t
he%20levels%20needed%20for%20stability.
•https://knowledge.aidr.org.au/resources/earthquake-christchurch-new-zealand-2011/
•https://www.police.govt.nz/news/major-events/previous-major-events/christchurch-earthquake
•https://my.christchurchcitylibraries.com/christchurch-and-canterbury-earthquakes/
•https://fastercapital.com/topics/historical-events-and-liquefaction.html
•https://gsa.confex.com/gsa/2005AM/webprogram/Paper91667.html
•https://link.springer.com/article/10.1007/s11440-021-01169-x
•https://www.linkedin.com/pulse/various-types-bearing-capacity-failures-foundations-qto-construction/
•https://link.springer.com/article/10.1007/s10064-015-0790-1