Measurement swelling pressures transmitted to structures and reducing these pressures by compressible materials

SUMMARY Measurement Swelling Pressures Transmitted to Structures and Reducing These Pressures by Compressible Materials Some soils can swell and shrink due to the varation of their water contents. When the soils, named as swelling soils or expansive soils, are blocked to swell freely by building up the constructions to their upper surface, a big amount of streches, defined as swelling pressure, can be appeared. Determining the shape transformation by these stretches is a very important problem. Also, getting the correct field data is very difficult in most conditions. The aim of this study is the measurement of applied pressure by establishing with the experimental model of applied pressure above or inside the swelling clays, structures. The volume changes of the investigated fields can be predicted with the estimation of these pressures and factors which effect the swelling. So, required preventations could be possible. Two models have been assembled for this aim direction. Respectively, large model in 80*105*20 cm. dimensions and small model in 25*25*30 cm. dimensions. Increment of the lateral swelling pressures at the certain depth and reduction of swelling pressure at the same depth, have been observed at a large laboratory model which was assembled at this study. Expanded Polysytrene Sytrofor (EPS) and cohesive nonswelling soils (CNS) have been used in a smaller experimental model and odemeter tool, in order to reduction transmitted swelling pressure. A very important amount reduction on the lateral and vertical swelling pressures have been determined. According to the results, lateral and vertical swelling pressures have been reduced by increasing of EPS thickness. Also, EPS which has been placed the backing of laboratory model has been found more effective in order to reduce swelling pressures, compared with the CNS at the same thickness of EPS. Reduction of transmitted swelling pressures will provide a great amount of benefit to the economy, considering construction of many structures which are damaged due to transmitted swelling pressures every year in our country. Key Words: Swelling Soils, Expansive Soils, Swelling Percentage, Lateral Swelling Pressure, Vertical Swelling Pressure, EPS. DC