Drying Wetting Effect On The Physical Characteristics of Bobonaro Clay (Case Study: East Nusa Tenggara Province, Indonesia)

Abstract

The Motaain-Henes-Motamasin route, which forms the eastern boundary between the Republic of Indonesia and the Democratic Republic of Timor Leste, includes Dafala-Laktutus STA.149+140. This route is managed by the East Nusa Tenggara BPJN. In the East Nusa Tenggara province, numerous road projects close to the border between RI and Timor Leste were constructed on challenging clay soil from the Bobonaro clay deposit. This suggests that a landslide has occurred along the road portion. Thus, it is crucial to investigate the properties of this Bobonaro clay. Drying and wetting experiments were conducted on a laboratory scale for a maximum of three (3) cycles in this study. Soil samples in the remolded disturb condition—the starting circumstances of the first undisturbed soil test results with wetting-drying test intervals per 25% moisture content (w)—were used to create the specimens for the wetting-drying test. Volumetric gravimetric testing and suction testing using the ASTM D 5298-03 Soil Suction Method with Filter Paper are used to determine the physical characteristics of the soil. The physical characteristics of Bobonaro clay usually decrease over the wetting-drying cycle. Between the first and third cycles, the dry volume weight, γd [kN/m3], fell by 4.043%, the void ratio, e, increased by 13.82%, and the negative pore water pressure (-Uw) reduced by 66.71%. The Bobonaro clay exhibits strong swelling and shrinkage capabilities, akin to expansive soil behavior, as evidenced by notable variations in the water content (w), void ratio (e), and negative pore water pressure (-Uw).