<![CDATA[Permeability and bearing capacity are key parameters in geotechnical engineering that are strongly influenced by grain gradation, particle morphology, and the arrangement of granular materials. This study aims to investigate the effect of engineered sand gradation on the permeability and bearing capacity characteristics of granular materials through theoretical and experimental approaches. The materials consisted of Bali Sand, Cibeet Sand, and Serayu Sand, which were combined using mixture theory to produce different gradation configurations. Material characterization included specific gravity testing, sieve analysis, particle morphology observation, and laboratory permeability testing. The measured permeability coefficients were subsequently compared with theoretical predictions obtained from the Hazen and Chapuis equations. Furthermore, the relationship between permeability and bearing capacity was evaluated through empirical correlations with the California Bearing Ratio (CBR) and estimated N-SPT values, followed by verification using direct shear testing based on the internal friction angle. The results demonstrate that engineered gradation producing denser particle arrangements through a void filling mechanism effectively reduces permeability while improving the mechanical performance of granular materials. These findings indicate that engineered sand gradation is a promising approach for enhancing granular material performance in geotechnical applications and contributes to the achievement of Sustainable Development Goal (SDG) 9 by promoting more efficient and sustainable construction materials. Abstrak Permeabilitas dan daya dukung merupakan parameter penting dalam rekayasa geoteknik yang dipengaruhi oleh gradasi, morfologi butiran, dan susunan material granular. Penelitian ini bertujuan menganalisis pengaruh rekayasa gradasi campuran pasir terhadap karakteristik permeabilitas dan daya dukung material granular melalui pendekatan teoritis dan eksperimental. Material yang digunakan terdiri atas Pasir Bali, Pasir Cibeet, dan Pasir Serayu yang dikombinasikan menggunakan mixture theory untuk memperoleh variasi gradasi yang berbeda. Karakterisasi material dilakukan melalui pengujian specific gravity, sieve analysis, pengamatan morfologi butiran, dan uji permeabilitas laboratorium. Nilai koefisien permeabilitas hasil pengujian kemudian dibandingkan dengan hasil perhitungan teoritis menggunakan persamaan Hazen dan Chapuis. Selanjutnya, hubungan antara permeabilitas dan daya dukung dianalisis melalui korelasi empiris terhadap nilai California Bearing Ratio (CBR) dan estimasi N-SPT, kemudian diverifikasi menggunakan pengujian direct shear berdasarkan nilai sudut geser dalam. Hasil penelitian menunjukkan bahwa rekayasa gradasi yang menghasilkan susunan butiran lebih rapat melalui mekanisme void filling mampu menurunkan permeabilitas sekaligus meningkatkan karakteristik mekanik material. Temuan ini menunjukkan bahwa rekayasa gradasi campuran pasir merupakan pendekatan yang efektif dalam meningkatkan kinerja material granular untuk aplikasi geoteknik serta mendukung pencapaian Sustainable Development Goal (SDG) 9 melalui pengembangan material konstruksi yang lebih efisien dan berkelanjutan.]]>
