A landslide occurred in the Awunio – Lapuko road section from STA 4+955 to STA 5+015, causing the road shoulder to collapse. It is estimated that the cause of this is the entry of water into the soil, affecting the properties of clay shale. An analysis of the existing slope stability and its planning needs to be done. Water management planning and alternative reinforcement are necessary if the stability does not meet the requirements. The slope stability analysis is conducted on the existing slope and the existing design using manual calculation methods and the GEO5 software. The stability aspects considered include overturning stability, sliding stability, bearing capacity, and overall stability. The analysis of the existing slope stability shows safety from landslide incidents. However, this contradicts the field observations, so a crack soil approach is used to understand the landslide conditions in the field, resulting in a safety factor (SF) of 0.95. The existing design, which includes a retaining wall with bored piles, yields a slope stability with an SF of 7.87. Water management system planning indicates that the drainage channel capacity can still accommodate the water flow resulting from rainfall. The construction of subdrains increases the SF on the slope to 1.38 but requires additional reinforcement. The retaining wall design with bored pile results in a slope stability 2.11. Meanwhile, the alternative of subdrains with additional geotextile reinforcement yields a slope stability of 1.96. The alternative geotextile design achieves slope stability with an SF of 1.77, ensuring safety and meeting stability requirements.

Abramson, Lee. W., Lee, Thomas. S., Sharma, S., & Boyce, G. M. (2002). Slope Stability and Stabilization Method (2nd ed.). John & Wiley Sons, Inc.

Alhadar, S., Asrida, L., Prabandiyani, S., & Hardiyati, S. (2014). “Analisis Stabilitas Lereng Pada Tanah Clay Shale Proyek Jalan Tol Semarang-Solo Paket VI STA 22+700 sampai STA 22+775”. Jurnal Karya Teknik Sipil, Vol. 3, Hal.: 336–344. Semarang.

Departemen Permukiman & Prasarana Wilayah. (2002). Panduan Geoteknik 4: Desain dan Konstruksi. WSP International. Bandung.

Hardiyatmo, H. C. (2003). Mekanika Tanah II (3rd ed.). Gadjah Mada University Press.

Hardiyatmo, H. C. (2006). Penanggulangan Tanah Longsor dan Erosi. Gajah Mada University Press.

Hardiyatmo, H. C. (2010). Analisis & Perancangan Fondasi II. Gadjah Mada University Press.

Hardiyatmo, H. C. (2014). Analisis & Perancangan Fondasi (2nd ed., Vol. 1). Gadjah Mada University Press.

Manudianto, Dedy., Endah, Noor., & Siahaan, Hardy P. (2023). “Alternative of Soil Improvement Methods on Organic Soil Using Preloading and Vertical Piles for Embankment with Varied Heights. Case Study: Construction of Batanjung Port Access Road in Pulang Pisau Regency, Central Kalimantan”. Journal of Infrastructure and Facility Asset Management. Vol. 5, No. 1, Hal.: 11-26. Surabaya.

Mochtar, I. B. (2021). The Phenomena of Cracked Soil. Institut Teknologi Sepuluh Nopember.

NAVFAC DM-7. (1971). Design Manual - Soil Mechanics, Foundations, and Earth Structures. U.S Naval Publications and Forms Center.

Satrya, T. R., Soemitro, R. A. A., Maulana, M. A., & Soetanto, R. (2019). “Assessment of Infrastructure Assets InducedbyWaterLevel Fluctuation along the Bengawan Solo River”. Journal of Infrastructure and Facility Asset Management. Vol. 1, No. 2, Hal.: 105. Surabaya.

Seftian, E., Sumampouw, R. J. E. R., & Balamba, S. (2015). “Analisis Daya Dukung Tiang Pancang Dengan Menggunakan Metode Statik dan Calendring Studi Kasus : Proyek Pembangunan Manado Town Square 3”. Jurnal Sipil Statik, 3(9), 631–643. Manado.

Shoffiana, Nur A., Lastiasih, Yudhi., & Satrya, Trihanyndio R. (2022). “Comparison of Embankment Reinforcement Requirements with Geotextile on Soft Soil with 2D and 3D Slope Stability Analysis Methods”. Journal of Infrastructure and Facility Asset Management. Vol. 4, No. 2, Hal.: 65-78. Surabaya.

SNI 2847. (2013). Persyaratan Beton Struktural Untuk Bangunan Gedung. www.bsn.go.id

SNI 8460. (2017). Persyaratan Perancangan Geoteknik. www.bsn.go.id

Soemitro, R. A. A., & Suprayitno, H. (2019). “Preliminary Reflection on Basic Problematics of National Public Infrastructure Financing in Indonesia”. Journal of Infrastructure and Facility Asset Management. Vol. 2, No. 1, Hal.: 51. Surabaya.

Suprayitno, H., Soemitro, R. A. A., Maulana, M. A., & Hesna, Yervi. (2020). “Preliminary Reflection on Performance Indicator and Performance Factor for Infrastructure Asset Management”. Journal of Infrastructure and Facility Asset Management. Vol. 2, No. 1, Hal.: 35. Surabaya.

Tarigan, B. A. C., Mochtar, I. B., & Arif, M. (2020). “Rekomendasi Solusi untuk Mengatasi Kelongsoran pada Lereng Jalan Akses PLTA Musi (KM 5 dan KM 8) dengan Pendekatan Cracked Soil”. Jurnal Teknik ITS, 9(2), 265–271. Surabaya.