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Unformatted text preview: LKOTE New Delhi Mem hers
DEPUTY DIRECTOR ( CSMRS Shri R. S. Melkote
SHRI V. S. AQQARWAL ) ) ( Alfernafc to SHRI AMAR SINQH ( Alternate)
PROF ALAY SINQH
DR A. BANERJEE
DEPUTY
D I R E c T o R RESEARCH
( FE),
RDSO Cent;iadora~~~lding Research Institute University of Jodhpur
Cementation Company Ltd, Bombay
Railway Board ( Ministry of Railways ASSISTANT DIRECTOR RESEARCH
( SOIL MECH ), RDSO
( Afternate) (CSIR), ) ( Continued on page 2 1 ) 2 IS: 9214 1979 Indian Standard
METHOD OF DETERMINATION
OF MODULUS
OF SUBGRADE REACTION (KVALUE)
OF SOILS IN FIELD
0. FOREWORD .O.l This Indian Standard was adopted by the Indian Standards
Institution on 5 June 1979, after the draft finalized by the Soil Engineering
and
Rock Mechanics
Sectional Committee
had been approved
by the Civil
Engineering
Division Council,
0.2 The ’ modulus of subgrade reaction test ‘, usually known as Kvalue
test, is essentially a plate bearing test. This test is used for the design of
pavement structures and raft foundations.
0.3 Like all other soil strength
tests, Kvalue test will not provide
a
representative
measurement
of subgrade strength unless performed
under
the conditions that would be expected after equilibrium
of the subgrade
with the environmental
influences of moisture, density, frost, drainage and
Equilibrium
is not attained
until the structure has been supertraffic.
imposed upon it for some time.
0.4 In the formulation
of this standard
due weightage has been given to
international
coordination
among the standards
and practices prevailing
in different countries in addition to relating it to the practices in the field
in this country.
0.5 In reporting the result of a test or analysis made in accordance
with
this standard, if the final value, observed or calculated,
is to be rounded ,
off, it shall be done in accordance
with IS : 21960*.
1. SCOPE
1.1 This standard deals with the method for the determination
of modulus
of subgrade reaction of the soil in place (generally
known as Xvalue of
the subgrade ), for evaluation of strength of subgrade for roads, runway
pavements and raft foundations.
*Rules for rounding off n;:merical valllw (reuised 3 ), IS : 9214  1979
2. TERMINOLOGY
2,0, For the purpose of this standard,
1972* and the following shall apply. the definitions given in IS : 2809 2.1 Modulus
of Subgrade
Reaction
 Ratio
of load per unit area
( applied through a centrally loaded rigid body ) of horizontal
surface of
a mass of soil to corresponding
settlement of the surface.
It is determined
as the slope of the secant drawn between the point corresponding
to zero
settlement
and the point of 1.25 mm settlement,
of a loadsettlement curve obtained
smaller loading from a plate load test on a soil using a 75 cm diameter
plate with corrections for size of plate used. 2.2 Deflection The
amount
of downward
vertical
movement
due to the application
of a load to the surface. horizontal surface or
of a that the reaction
of the subgrade is
2.3 Kvalue  If the assumption
proportional
to the deflection is entirely correct, the curve in Fig. 1 should
be straight line and the slope of this line should give the modulus of sub,
grade reaction measured in MPa/cm ( kgf /ems/cm ). The results, however,
usually give a curve which is convex upwards and which has no straight
portion even initially, Kvalue is, therefore,
taken as the slope of the line
passing through the origin and the point on the curve corresponding
to
1.25 mm settlement (see Fig. 1 ):
K =&...
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This note was uploaded on 03/14/2014 for the course CE 684 taught by Professor Prof.deepankarchoudhury during the Spring '13 term at IIT Bombay.
 Spring '13
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