THE PREPARATION OF SUBGRADES

FOR SOFT SOILS IN EMBANKMENTS, COMPACTION IS OBTAINED BY USING SPECIAL ROLLING EQUIPMENT. FOR CLAYEY SOILS, AN INSULATING LAYER OF SAND, GRAVEL OR SLAG VARYING IN THICKNESS FROM 10 TO 30 CM IS USED TO PREVENT CAPILLARY MOISTURE FROM ESCAPING INTO THE PAVEMENT. DRAINAGE DESIGN IS IMPORTANT.