AbstrakWilayah Indonesia yang berada pada belahan dunia yang memiliki iklim hujan tropis menyebabkan bervariasinya intensitas curah hujan. Intensitas curah hujan akan sangat berpengaruh pada kestabilan tanah sebagai dasar pondasi sebuah struktur sipil. Dalam penelitian ini ditinjau pengaruh intensitas curah hujan dan kemiringan lereng dalam upaya pencegahan kerusakan struktur maupun kejadian bencana yang dapat ditimbulkan. Dilakukan pengujian laboratorium dengan menggunakan metode pembanding Universal Soil Loss Equation untuk menentukan besarnya erosi yang terjadi pada lereng tanah dengan kadar organik 18,67% dengan tingkat kepadatan 60% dan 70%. Dengan menggunakan Rainfall Simulator digunakan variasi intensitas hujan 23 mm/jam, 34 mm/jam dan 51 mm/jam diperoleh peningkatan nilai erosi tanah sebesar 40% dari intensitas tertinggi ke intensitas terendah. Dari faktor kemiringan lereng dimodelkan kemiringan 10 o , 15 o dan 20 o dan didapatkan hasil peningkatan nilai erosi sebesar 3%. Abstract The Effect of Rainfally and Land Slope to Erosion which Could Cause A Landslide.Indonesian region is located on tropical rain forest territory on earth causes variations of high intensity of rainfall. The intensity of rainfall will great ly affect the stability of soils as a foundation ground of a civil structure. In this study reviewed the influence of rainfall intensity and slope in the prevention of structural damage or catastrophic events that may occur. Experimental research conduct using comparison method Universal Soil Loss equation to determine the amount of erosion on the slope of ground with organic content of 18.67 with a density of 60% and 70%. Rainfall simulator used to set variations of rainfall intensity by 23 mm/hour, 34 mm/hour and 51 mm/hour is obtained an increase in ground erosion by 40% from the highest intensity to the lowest intensity. From the slope factor, sample is modeled slope with 10 o , 15 o and 20 o and showed increase of erosion up to 3%. Kata-kunci:Erosi lereng, intensitas hujan, tanah organik .

South Sulawesi is one of eastern Indonesia area covered with coastal line which have growth fast of industries. Infrastructure builds and developed in a row of industries population. Most coastal are lowland areas with expansive soil as primary soil forms. Exhaustive laboratory test conducts for clay taken from lowland area in south Sulawesi and lime up to 10% and volcanic up to 25% as stabilizers to know the Physical-mechanical properties and mineralogical when the expansive soil stabilized. The extensive soil stabilized with 5% lime + 15% Volcanic ash presents better performance and pass the roadbed materials requirements. Chemical reactions between soil and the stabilizers increase the pH and electrical conductivity. X-ray diffraction (XRD) and transmission electron microscope (TEM) confirmed new cementing agents’ findings regarding the results of chemical reactions. An explicit effect on controlling the soil deformation and the moisture change shows by the expansive soil stabilized with 5% lime + 15% volcanic ash. The research results find the optimum combination of stabilizers to reduce cost to improve expansive soil from the South Sulawesi lowland area.