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Aceh located in earthquake disaster-prone area because it is located between two tectonic plates and also surrounded by several active volcanos. When earthquakes shake, the building frequency (f) should not be equal to the natural soil frequency (fn) as it may cause the collapse of buildings. The purpose of this study is to determine dynamic seismic parameters value on the surface layers for forthcoming disaster mitigation. The object study for this research were Rahmatullah Lampuuk Mosque, Sultan Iskandar Muda Airport, Lambaro Bridge in Aceh Besar, TDMRC building, and Taman Sari. Soil samplings from the locations and data obtained from the BMKG such as earthquake center map, coordinates, magnitude, and earthquake depths were used in the study. The result of this research was Gmax value based on Richart method. Kramer method was also used for computing the fn parameters. Some static and dynamic calculation of design parameter result from Rahmatullah Lampuuk Mosque shows that with void ratio (e) = 0.92, the Gmax = 266 × 103 kg/ms2, Vs = 10.096 m/s and fn = 2.524 Hz. The comparison of fn and fstructure = 2.50 Hz which not equal to zero make the building were safe from collapse during previous earthquakes in Aceh.

Analysis of slope stability in this study aims to determine the safety factor (SF) of the landslide for the existing and the reinforcement condition. The study case was in STA 84+910 of national road Meulaboh-Geumpang, West Aceh Regency in Aceh Province. The condition of the Meulaboh-Geumpang road often causes landslides due to the topography of the area and is also triggered by rainfall. The analysis of safety factor for the existing condition was calculated by using the Bishop method that assumes a circular failure surface and the calculation was also validated by the finite element method using 2D Plaxis version 8.6 software. However, computation requires iterative procedures because of the nonlinear relationship for the safety factors. The result obtained from calculations using the Bishop method for the existing condition is 1.08, while by using Plaxis software, the result is 1.10, which means the slopes are in unstable conditions and need to be reinforced to prevent landslides. Alternative reinforcement was conducted by using sheet pile and calculations performed using 2D Plaxis version 8.6 software. Variations in the placement of sheet piles are at the upper and middle of the slope. The results obtained from the calculation of the safety factor after reinforcement are 1.57 (with a 12m sheet pile depth at the upper slope) and 1.48 (with a 10m sheet pile depth in the middle of the slope).

Soil stabilization is the modification process of one or more soil properties mechanically or chemically to generate an improved soil material with the appropriate engineering properties. Recently, stabilization methods utilizing commonly used stabilizing agents are becoming more costly. On the other hand, there is an increasing interest in identifying new green technologies that may be used to improve construction practices. As a result, the search for new materials and improved processes for processing local materials has moved to a priority. Thus, this study was conducted to validate the effectiveness of coffee husk ash (CHA) as a stabilizing agent on the compaction characteristics of clayey soil. To characterize the properties of clayey soil admixed with varying concentrations of CHA, Atterberg limits, grain size distribution, and standard proctor compaction tests were conducted. The soil was mixed with CHA in concentrations ranging from 5% to 25% by dry weight of the soil. Observation indicates CHA progressively enhances soil compaction performance. The pozzolanic and hydration reactions between CHA and the soil may have made the soil more likely to be compacted.