Analisis Potensi Likuifaksi Menggunakan Data SPT (Standard Penetration Test) (Studi Kasus Proyek Pembangunan Jalan Tol Binjai-Pangkalan Brandan STA 17+425 Zona 2 Kuala Madu SD. STA 28+200 Zona 3 Gohor Lama)

Abstract

Indonesia is one of the countries with a high probability of an earthquake occurring. This is due to Indonesia's location at the confluence of three main tectonic plates: the Indo-Australian Plate, the Indo-Chinese Plate, and the Pacific Plate, causing tectonic movements and volcanic earthquakes. Liquefaction is one of the phenomenon caused by earthquakes where as a result of earthquake vibrations there is a cyclic dynamic or alternating motion of earthquake waves which causes a shift in the soil layers so that there is a change in soil properties from solid to liquid. In order to identify the potential for liquefaction in a location, an empirical analysis can be carried out using SPT test data (Standart Penetration Test), laboratory data, and ground acceleration in bedrock calculated using the Joyner & Boore (1988) attenuation function and Crouse (1991) attenuation function and processed using the application Proshake 2.0 resulting in a peak ground acceleration. The research location is in the Binjai-Pangkalan Brandan toll road construction project (Phase 3) in the Kuala Madu-Gohor Lama area (sta 17+425 to sta 28+200). The results of the evaluation of liquefaction potential based on SPT data show that the bigger the peak acceleration, the bigger the cyclic stress ratio and it causes a smaller safety factor value as the result. A smaller factor of safety indicates liquefaction may occur. As for the results of the analysis of liquefaction potential in case I the layer that has the potential to be liquefied is sta 25+660 at a depth of 2.45 m - 4.45 m. For case II the layers that have the potential to be liquefied is Sta 17+425 at a depth of 0 m – 4.45 m; Sta 18+450 at a depth of 2.45 m – 4.45 m; Sta 25+660 at a depth of 0 m – 4.45 m; Sta 26+500 at a depth of 0 m – 2.45 m; Sta 28+200 at a depth of 0 m – 4.45 m. For case III the layer that has the potential to be liquefied is at Sta 25+660 at a depth of 2.45 m – 4.45 m. For case IV the layers that have the potential to be liquefied is at Sta 17+425 at a depth of 0 m – 4.45 m; Sta 18+450 at a depth of 2.45 m – 4.45 m; Sta 25+660 at a depth of 2.45 m – 4.45 m; Sta 28+200 at a depth of 0 m – 4.45 m