Tanah lempung ekspansif memiliki sifat dan karakter tanah yang merugikan karena sifat kembang susutnya. Bila suatu konstruksi dibangun di atas tanah ekspansif maka akan terjadi berbagai kerusakan antara lain lantai bergelombang dan dinding rumah mengalami keretakan yang berdampak pada ketidaknyamanan penghuni rumah.

Salah satu upaya untuk mengatasi problema tanah ekspansif kembang-susut yaitu dengan stabilisasi tanah. Pada penelitian ini akan dilakukan eksperimen untuk menaikkan nilai kuat tekan bebas  (qu) tanah lempung di daerah Panempan, Madura, dengan cara menambahkan serbuk cangkang kerang sebagai bahan stabilisasi. Dalam penelitian ini dilakukan berbagai macam uji antara lain, uji Konsistensi Tanah, uji Specific Gravity (Gs), uji Standar Proktor, dan uji Kuat Tekan Bebas (qu) dengan masing – masing variasi penambahan serbuk cangkang kerang 0%, 10%, 15%, 20%, 25%, dan 30% dari berat tanah.

Hasil penelitian menunjukkan bahwa penambahan 0%, 10%, 15%, 20%, dan 25% serbuk cangkang kerang menyebabkan peningkatan nilai kuat tekan tekan bebas berturut – turut sebesar 1,045 kg/cm², 1,855 kg/cm², 2,482 kg/cm², 2,865 kg/cm², dan 3,435 kg/cm². Penambahan 25% serbuk cangkang merupakan persentase yang paling efektif sehingga meningkatkan nilai maksimum kuat tekan bebas.

Kata Kunci:  Tanah lempung ekspansif, serbuk cangkang

kerang, daya dukung pondasi dangkal

Expansive clay has adverse soil properties and characteristics because of the shrinkage properties. If the construction is built on expansive soil, there will be damages such as corrugated floor and cracking walls that have an impact on the inconvenience from the occupants of the building.

One effort to overcome the problem of expansionary soil shrinkage is stabilization of the soil. In this study an experiment will be conducted to increase the value of Unconfined Compression Test (qu) in clay which is located in Panempan, Madura that is by adding clamshell powder as a stabilizing material. In this study various tests will be carried out, namely: Soil Consistency test, Specific Gravity Test (Gs), Standard Proctor Test, and Unconfined Compression Test (qu) with each variation of the addition of clamshell powder 0%, 10%, 15%, 20%, 25%, and 30% of the weight of the soil.

The results showed that the addition of 0%, 10%, 15%, 20%, and 25% of clamshell powder caused an increase in the value of Unconfined Compression Test in a row of 1,045 kg/cm², 1,855 kg/cm², 2,482 kg/cm², 2,865 kg/cm², dan 3,435 kg/cm². Addition of 25% of the shell powder is the most effective percentage which increases the maximum value of Unconfined Compression.

Keyword:  Expansive clay, clamshell powder, bearing

capacity of shallow foundation.