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 Topic: Geotechnical design and analysis Subject: subgrade modulus
 Author: Nejat Ozcimen 2001-07-12 hidoes anybody has info. about the subgrade modulus coefficient, k (t/m3) can be used for the settlement amount?if the mat foundation system is rigid and the layer below it is sandy silty clay; as far as i know it can not be used for the settlement calculations. it is only used for differencial deformations.?empric correlations recommended for the k coefficient is 1500-2000 t/m3 for this soil structure.But if you calculate that from the formula (Braja Das. "princ. of foun. engng.)it will be app. 150-200 t/m3.and consequently:if you use emprical values the settlement value is 1-2 cm.and if the other, the sett. is 12-13 cm. if i calculate the settlement by classical stress distribution method, it will be 15 cm. i use this modulus as a soil parameter to the SAP2000 programme.would you tell me that which value is reliable? and can i calculate the settlement amount by this way?..thanks.. Reply to this posting
Follow-up:
 Author: Nejat Ozcimen 2001-07-13 thank you Paul,i have two things that i need more info?1st as far as i understand, the subgrade reaction coefficient Kh (t/m3) can not be used for the setllement analysis. it is only used for deflection of the foundation.?is settlement only determined by E (t/m2) layer by layer?2ndif i derive Kh (t/m3) by Kh=E/b(1-u2) it is app. 100-150 t/m3 but emprical correlations give 1500-2000 t/m3. in addition, 1st value represents very soft and slime soil condition? but it is not really. what is the difference betw. them.?thanks..