Abstrak Tanah lunak memiliki karakteristik daya dukung rendah, konsistensi lunak, potensi penurunan tinggi, dan stabilitas rendah yang dapat menyebabkan ketidakmampuan tanah dalam menahan beban konstruksi, sehingga penerapan metode perbaikam tanah menjadi keharusan. Penelitian ini menggunakan metode stabilisasi untuk memperbaiki tanah dengan penambahan tanah pedel dan silica fume untuk meningkatkan sifat mekanis dan kimiawi tanah, melalui pengujian UCS, triaksial, dan ED-XRF. Variasi tanah pedel yang digunakan yaitu 3%, 6%, 9%, dan 12%, kemudian persentase optimum tanah pedel dikombinasikan dengan 7,5% silica fume. Hasil menunjukkan bahwa tambahan tanah pedel 9% merupakan variasi paling optimum, terjadi peningkatan kuat tekan bebas hingga 691%, kohesi 296%, dan sudut geser 115% jika dibandingkan tanah asli pada masa peram 14 hari. Kombinasi tanah pedel 9% dan silica fume 7,5% juga meningkatkan kuat tekan, kohesi dan sudut geser tanah berturut turut hingga 756%, 311%, dan 138% jika dibandingkan dengan tanah asli pada masa peram yang sama. Peningkatan ini dipengaruhi reaksi kimia pembentukan Calcium Silicate Hydrate (CSH) dari interaksi CaO pada tanah pedel dan SiO₂ silica fume. Kata kunci: Stabilisasi, Tanah Lunak, Tanah Pedel, Silica Fume, Calcium Silicate Hydrate (CSH) Abstract Soft soil is characterized by low bearing capacity, soft consistency, high settlement potential, and low stability, which can lead to the soil’s inability to support construction loads; therefore, the application of soil improvement methods becomes essential. This study employs a stabilization method to improve soil by adding pedel soil and silica fume to enhance the mechanical and chemical properties of the soil, through UCS, triaxial, and ED-XRF tests. The pedel soil contents used were 3%, 6%, 9%, and 12%, after which the optimum pedel soil percentage was combined with 7.5% silica fume. The results show that the addition of 9% pedel soil is the most optimum variation, resulting in increases in unconfined compressive strength of up to 691%, cohesion by 296%, and internal friction angle by 115% compared to the natural soil at a curing period of 14 days. The combination of 9% pedel soil and 7.5% silica fume further increased the unconfined compressive strength, cohesion, and internal friction angle by 756%, 311%, and 138%, respectively, compared to the natural soil at the same curing period. These improvements are influenced by the chemical reaction forming Calcium Silicate Hydrate (CSH) from the interaction between CaO in the pedel soil and SiO₂ in the silica fume. Keywords: Stabilization, Soft Soil, Pedel Soil, Silica Fume, Calcium Silicate Hydrate (CSH)