Studi nilai kuat geser tanah hambalang berdasarkan kadar air

Soft soils have low strength and easy to compress when they are loaded. A soil compaction test is performed to measure maximum soil density at the optimum water content to evaluate the strength of soft soil. To maintain these circumstances, however, efforts are necessary to preserve the water content at optimal levels, which is not easy. In actual condition the compacted soil can still be penetrated by water through soil cracks occurred especially on the slopes. The shear strength of the soil will decrease if rainwater infiltration is excessive. In a laboratory investigation, direct shear testing (ASTM D3080 - SNI 3420:2016) was used to determine how changes in the value of the Hambalang clay soil shear strength as reflected by the cohesion value (c) and the soil shear angle (f). Creating soil samples with a fixed density and variations in water content (w). The test results at w = 14.47% obtained c = 0.047 kg/cm2, f = 45.75⁰; at w = 21.75% obtained c = 0.203 kg/cm2, f = 33.39⁰, at w = 26.62% obtained c = 0.186 kg/cm2, f = 24.10⁰, at w= 31.59% obtained c = 0.086 kg/cm2, f = 21.90⁰ and at w = 33.70% obtained c = 0.082 kg/cm2, f = 21.21⁰. From these results it can be concluded that the largest of cohesion and angle of internal friction or strength parameter values will reach at optimum moisture content.