Dear Selvakumar,

Please check the following useful links.

https://www.researchgate.net/publication/223088387_Laboratory_assessment_of_swelling_pressure_of_expansive_soils

https://www.academia.edu/5343437/Critical_Evaluation_of_Determining_Swelling_Pressure_by_Swell-Load_Method_and_Constant_Volume_Method

http://www.nrcresearchpress.com/doi/abs/10.1139/T10-074#.V8FW0WG6bDc

http://link.springer.com/article/10.1007/s11440-008-0057-0

https://www.researchgate.net/post/How_do_I_measure_swelling_pressure_of_expansive_soils

https://www.researchgate.net/post/I_would_like_to_measure_the_swelling_pressure_exerted_by_the_soil_expansive_upon_interaction_with_water_Any_suggestions_about_the_sensors_to_be_used

Good Luck

Article Laboratory assessment of swelling pressure of expansive soils

Please check these two attachments also.

Thanks aravind