Masalah yang umumnya muncul terkait dengan konstruksi bangunan pada tanah lunak di Kota Tarakan adalah daya dukung yang kurang baik, Permasalahan daya dukung tanah dapat diatasi dengan melakukan perbaikan tanah dengan cara stabilisasi tanah. Penelitian ini membahas tentang stabilisasi tanah lempung lunak dengan menggunakan stabilizer (kapur, oksida besi dan bubuk damar). Pengujian ini bertujuan untuk mengetahui pengaruh penambahan stabilizer dan pengaruh lama masa peram yang paling maksimum pada tanah lempung di Kampung Empat Kota Tarakan. Adapun metode penelitian yang digunakan pada penelitian ini adalah metode eksperimental dan dilakukan dalam skala laboratorium. Persentase penambahan bahan stabilisasi adalah sebesar 20%, 25%, dan 30% dengan masa peram selama 10 hari, 20, 30 hari dan 40 hari. Hasil penelitian menunjukan perubahan sifat fisik dan CBR meningkat paling maksimum pada penambahan campuran 30% dan masa peram 40 hari. Perubahan sifat fisik berupa kadar air turun 46,89%, berat volume tanah naik 12,92%, spesifik gravity naik 17,24%, Analisa saringan turun 85,01%, batas cair turun 12,04%, batas plastis naik 41,82% dan indeks plastis turun 51,37%. Perubahan sifat teknis diperlihatkan dengan meningkatnya nilak CBR menjadi 220,89%.

Kata Kunci : Tanah lempung lunak, Bubuk Damar, Kapur, Oksida Besi, Stabilisasi, CBR

The instability of soft clay soil with low bearing capacity is the issue with building construction in Tarakan. Enhancing or stabilizing soil can solve the issue of soil carrying capacity. The stabilization of soft clay soil employing stabilizers (lime, resin powder, and iron oxide) is covered in this study. This study sought to establish the maximum length of the peram period in Kampung Empat, Tarakan, as well as the effects of adding a stabilizer and measuring the proportion of stabilizer material. This study employed an experimental research design and a small-scale laboratory setting. The soil's physical and technical characteristics were determined to be W 70.072%, 1.47, Gs 2.68, passed sieve No. 200 85.17%, LL. 55.58%, PL 18.22%, and IP 37.36% in Tarakan, North Kalimantan. The soil stabilization found adding a stabilizer to soft clay soil might change its technical and physical characteristics. However, with a cooling interval of 10 days, 20 days, 30 days, and 40 days, the technical qualities of the soil for stabilizer changes were 20%, 25%, and 30%. The tests revealed a rise in volume weight, specific gravity, CBR values, and a decrease in soil particle size and water content. The best or maximum bearing capacity value was attained at a stabilizer combination of 30% and a 40-day curing time. Keywords: Resin Powder, Lime, Iron Oxide, Stabilization