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Earthquake: the word itself feels disastrous. Though the earthquake has no direct effect on human being, but still it causes a plenty of life and property loss. The reason is earthquake tends to fail the various structures such as buildings, houses, bridges, roads etc. and this failure causes all losses. The following pictures shows some of the failure of structures due to earthquake. But please hold for a minute, in case of the following failed structures, it was possible to prevent the failure…… Because these structures are not failed only due to earthquake but because of failure of soil strata bellow the structure due to the earthquake. And if the soil was improved before construction the failure could be avoided. This phenomenon of failure of soil strata during earthquake is called as the “Soil Liquefaction”. Liquefaction is responsible for extreme property damage & loss of life due to several variations in failure potential. Still the liquefaction is not given that much importance. In India during Bhuj Earthquake lots of structures are collapsed due to liquefaction itself. And there are many liquefaction prone areas are present in zone IV in India. That’s why liquefaction is very much important. In this paper, the study of liquefaction is done with respect to its introduction, properties of soil in which the liquefaction may occurs, how exactly the liquefaction takes place, detailed Geotechnical Study of liquefaction which includes how to decide the liquefaction prone area, evaluation of liquefaction potential and the various old and recent remedial measures to avoid the liquefaction, along with software and Artificial Neural Network. So that one can become safe against Liquefaction.
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Paper PresentationPaper Presentation
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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