Presentation on liquefation @ pvkk by raghavendra
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A MAJOR CAUSE OF STRUCTURAL FAILURE DURING EARTHQUAKE
R. RAGHAVENDRA P.HEMANTH III B.Tech, Civil III B.Tech, Civil [email protected] [email protected]
FROMJ.N.T.U College of Engg.,Anantapur.
For
P.V.K.K TECHNO FEST 2K11
BE SAFE AGAINST BE SAFE AGAINST
““LIQUEFACTION”LIQUEFACTION”
INTRODUCTION
DEFINITION
GROUND FAILURE RESULTING FROM SOIL LIQUEFACTION
EXPLANATION OF LIQUEFACTION
MODES OF LIQUEFACTION
ANALYSING LIQUEFACTION SUSCEPTIBLE
GEOTECHNICAL STUDY ON LIQUEFACTION
ANALYSIS OF LIQUEFACTION
HOW CAN THE RISK OF DAMAGE DUE TO SOIL LIQUEFACTION BE
REDUCED?
CONCLUSION
REFERENCES
INTRODUCTION• What is liquefaction?• Relation with earthquakes• Quick sand?....
Castro & Polus
"Liquefaction is a phenomenon where in a
mass of soil loses a large percentage of
its shear resistance, when subjected to
monotonic, cyclic, or shock loading, and
flows in a manner resembling a liquid until
the shear stresses acting on the mass are
as low as the reduced shear resistance."
Ground Failure Resulting From Soil
Liquefaction:
• Sand boils • Flow failures of slopes
• Lateral spreads • Ground oscillation
• Loss of bearing capacity • Buoyant rise
• Ground settlement • Failure of retaining walls
Explanation of liquefaction
CONTACT FORCES IN SOILCONTACT FORCES IN SOILSOIL BEFORE LIQUEFACTION SOIL AFTER LIQUEFACTION
MODES OF LIQUEFACTIONMODES OF LIQUEFACTION
FLOW LIQUEFACTIONFLOW LIQUEFACTION
QUASI LIQUEFACTIONQUASI LIQUEFACTION
SAND BOILINGSAND BOILING
LIQUEFACTION BY ROBERTSONLIQUEFACTION BY ROBERTSON A. FLOW LIQUEFACTIONA. FLOW LIQUEFACTION B. CYCLIC B. CYCLIC
SOFTENINGSOFTENING
1) Cyclic liquefaction1) Cyclic liquefaction
2) Cyclic mobility2) Cyclic mobility
LIQUEFACTIONLIQUEFACTION SUSCEPTIBLE SUSCEPTIBLE
ANALYSING LIQUEFACTION SUSCEPTIBLE
There are a number of different ways to evaluate the liquefaction susceptibility of a soil deposit. Here they are organized as follows (adopted from Kramer, 1996).
a) Historical criteriab) Geo logical criteriac) Compositional criteriad) State criteria
STUDY ON LIQUEFACTION BY
GEO TECHNICIANS
1) Flow Liquefaction
2) Limited liquefaction
GRAPHS RELATED TO LIQUEFACTION
ANALYSIS OF LIQUEFACTION
A. Empirical correlation
B. simplified procedure
(by SEED AND IDRISS)
SIMPLIFIED PROCEDURE
MSF= Magnitude of scaling factorKa = Over burden scaling factorKc = Correction factor for sloping grouting
amax= Peak horizontal acceleration in ground when earth quake came
g = Acceleration due to gravity
rd =stress reduction coefficient
σvo and σ’vo are the total and effective overburden stresses
PROGRESS IN LIQUEFACTION
FINES CONTENT
MAGNITUED CORRELATED
DURATION WEIGHING FACTORS
EFFECTIVE OVERBURDEN STRESS
FINES CONTENT AND PLASTICITY INDEX
Applicable for
FC > 20% if PI>12%
FC > 35% if PI<12%
WEIGHTING FACTORS
SAFETY HOUSE FOR LIQUEFACTION
Properties
CONCLUSIONCONCLUSION We studied soil Liquefaction in Detail w.r.t. its importance,
properties of soil, details of Liquefaction, geotechnical study,
evaluation techniques and remedial measures and concluded that
liquefaction is very important phenomenon and it has not given
that much importance in India.
The detailed study of liquefaction must be undertaken for Indian
earthquake regions and the preventive measures must be
conducted in liquefaction prone area so as to avoid the failure of
structures during earthquake. So as to be safe against earthquake
failure.
REFERENCES
1) www.ce.washington.edu
2)what is soil liquefaction
- Alisha Kaplan.
3)Soil Liquefaction in Earthquake.
- Alan F. Rauch.
4) Soil Mechanics & Foundation Engineering.
- B. C. Punmia.
5) Liquefaction potential assessment in Chandigarh city.
- R. Dharmaraju & Gayatri Devi.
6)laboratory evaluation of dynamic properties and
liquefaction potential of sands
- Prof. T. G. Sitharam
RAGHAVENDRA & HEMANTH
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