CONTROL METHOD ANALYSIS ON FROST HEAVE WITH GEOTEXTILES AS THE EFFECT OF CAPILLARY BREAKS IN SOILS

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In order to develop the method of capillary breaks for the practical use, the laboratory experiments to prove the mechanism were conducted using several geotextiles, and field investigation was also carried out during three winters. The capillary rise experiment was first conduced to evaluate the potential of the several geotextiles. Then each geotextile was emplaced at mid-height in the soil column and water level was maintained at the same position. If a volcanic ash soil with high retention and high frost susceptivity was used, the potential of geotextiles was recognized for the effect of capillary breaks. In laboratory frost heave tests, the specimen was kept on the bottom at 4 C and was frozen from the too at -6 C.Consequently two kinds of thick geotextiles interpreted the uptake of water and indicated the effect of frost heave reduction by amounts below 50 percent. They were polyester geotextiles with three-layred structure and resin-bonding mat-shaped fabric, ranging from 7.5 mm to 10 mm in thickness. Some thin geotextiles did not show the effect of the reduction on frost heave. The field experiment was performed with several lysimeters under the constant water level conditions that was maintained at the 120 cm deep from the surface during three winters. The geotextiles were installed between the maximum frost penetration depth and the groundwater level. thick geotextiles, the same kinds used in the laboratory tests showed to be durable to reduce frost heave through three winters. In conclusion, it appears likely that the method of capillary breaks with geotextiles is significant for the remedies of frost heave control and the polyester geotextiles with thick structure were most effective to mitigate frost heave in soils.