S melkote new delhi mem hers deputy director csmrs

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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 (K-VALUE) 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 K-value 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, K-value 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 co-ordination 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 : 2-1960*. 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 X-value 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 load-settlement 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 K-value - 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, K-value 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 =&amp...
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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.

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