Stabilisasi tanah lempung lunak dengan abu sekam padi (rice husk ash) kampung satu kota tarakan. Tanah lempung merupakan tanah yang berukuran mikroskopis sampai dengan sub-mikroskopis yang berasal dari pelapukan unsur-unsur kimiawi penyusun batuan. Permasalahan yang biasanya timbul dari tanah lempung ini yaitu tingkat sensitifitasnya yang terlalu tinggi terhadap perubahan kadar air, sehingga perlu dilakukan stabilisasi, diantaranya dengan menggunakan abu sekam padi sebagai bahan stabilisasi. Pengujian sifat mekanis tanah dilakukan pada tanah lempung lunak yang bahan distabilisasi dan pada tanah lunak yang sudah distabilisasikan dan melewati masa peram. Komposisi campuran adalah SC : abu sekam padi 15% + 85%, 20% + 80%, 25% + 75%. Dan masa peram selama 7 hari, 14 hari, dan 28 hari. Dari Pengujian yang akan di lakukan di laboratorium maka diharapkan menggetahui berapa persen banyak bahan kimia abu sekam padi (rice husk ash) untuk distabilisasi yang harus dicampurkan pada tanah lempung lunak agar diperoleh hasil yang optimum dan mengetahui berapa lama waktu peram (curing time) yang paling baik pada tanah lempung lunak yang distabilisasi dengan bahan kimia abu sekam padi (rice husk ash) untuk mendapatkan hasil yang optimum.

Soft clay soil has physical and mechanical special characteristic, such as content high water, numbers of large pore, low unit weight, high plasticity index, so that it cause carrying capacity of soil clay soil to be low bearing capacity and high compressibility. As technical, it is not proper for construction of roads and buildings without deep foundation. The cases that often be faced are cracks even collapse, on roads it cause differential settlement and even collapsed , on the brigde it cause decreasing the level. One of technical to recovery soft clay soil is with fly ash stabilization method; it can be good result in some previous studies. The mixing materials stabilization are using some variation of the weight percentage of soil volume, which is additional rice husk ash 15%, 20%, and 25%. And also with some variations of curing time, which is 7, 14,and 28 days. The physical and mechanical characteristic experiments are performed on the original soft clay and soft clay that has been stabilizied with lime and after a curing time. Finally, from a series of experiments that conducted turns is mixing rice husk ash 25% on soft clay and the curing time 28 days provide optimum result in this study, with some indicators such ash : plastic index (PI) of 51,90% to be 7,15%, the water content (w) from 83,2% to be 40,9%; heavy volume of soil (?) of 1,28 gr/cm3 to be 1,15 gr/cm3 , specific gravity (Gs) dropped from 2,43 to be 2,75, direct shear cohesion value of 0.021 kg/cm2 to 0.55 kg/cm2 and the value of the friction angle of 37 0 be 18.6 0 and uncondfined compression test(UCT) from 0,09 kg/cm2 to be 0,49 kg/cm2