Imam A. Sadisun | Institut Teknologi Bandung (original) (raw)

Papers by Imam A. Sadisun

Journal of mechanical, civil and industrial engineering, Feb 13, 2023

Volcanic soil is often used as fill material in road embankment construction in Java island-Indon... more Volcanic soil is often used as fill material in road embankment construction in Java island-Indonesia. An understanding of the engineering properties of compacted volcanic soils is needed, especially during the preliminary design phase and during the detailed design phase of the road embankment. Carrying out a field compaction trial test will significantly assist in the design of the compaction process of the road embankment construction. Selecting the correct number of passes from the compactor and the engineering properties of compacted volcanic soils can be obtained from field compaction trial tests. Constrained modulus is one of the engineering properties that can indicate the stiffness of the fill material used in a road embankment. This study aims to determine the constrained modulus of compacted volcanic soil and compare it to the number of passes of a compactor from the field compaction trial test. The volcanic soil used in this study is classified as pumiceous tuff, which is derived from older volcanic rocks. The highest value of the oedometer modulus of compacted volcanic soils is 10.38 MPa which comes from eight (8) times passes of smooth drum roller conducted on field compaction trial test.

IOP Conference Series: Materials Science and Engineering

Most soil classification systems developed for geotechnical engineering purposes are based on sim... more Most soil classification systems developed for geotechnical engineering purposes are based on simple index properties such as grain size distribution and plasticity. In Indonesia, the use of the methylene blue value, VBS, is still rarely used, compared to Atterberg limits that commonly used to determine the value of the plasticity index, PI. Therefore, this study aims to gain a correlation between PI and VBS. Coarse-grained soil with fines (clay and silt) contents varies from 12.36% to 29.45% are used of this study. The linear correlation between PI and VBS produces a linear equation with a coefficient of determination, R2 = 0.854 for 0.62 < VBS < 2.39. The PI obtained from the correlation to VBS that combined with the sieve analysis results can then be used for soil classification based on the Unified Soil Classification System (USCS).

IOP Conference Series: Earth and Environmental Science

The landslide occurred in Sumampir of Purbalingga Regency has reached 120 m in length and 50 m in... more The landslide occurred in Sumampir of Purbalingga Regency has reached 120 m in length and 50 m in width. This landslide is suspected to be a retrogressive landslide, which was manned by a landslide associated with the cliffs of the Brangkal River. This landslide is interpreted as progressive development of a landslide associated with Brangkal river bank failures, which continues to enlarge to the dimensions as measured currently. The main active landslide has a steep scarp of along 60 m with a height of up to 8 m, with several transverse tensile cracks were found in between the scarp and above the crown. These tensile cracks have caused partial subsidence on the side of the village road that crosses it. In order to determine the existence of slip surface that have developed since the first landslide formed until the last one, an integrated technique of geoelectric resistivity and borehole logging has been applied. This integrated technique was then used to reconstruct the landslide ...

Jurnal Teknologi

The lower Cimanuk catchment area which will be developed as industrial area is dominated by Quate... more The lower Cimanuk catchment area which will be developed as industrial area is dominated by Quaternary deposits which are susceptible againts liquefaction if large earthquakes occurred. The presence of Subang, Cirebon 1 and Cirebon 2 active fault segments will trigger earthquake which potentially liquefaction. This study aims to characterize the type of sedimentary facies induced liquefaction hazard in the lower Cimanuk catchment area, Indramayu, West Java. This research methods consist of borehole description and sedimentary facies analysis based on CPT and CPTu data with cone resistance (qt) corrected value, friction ratio (Fr), laboratory analysis and liquefaction potential based on SNI 1726:2019, which is deterministic and 2,500 years return period PGA value. Based on facies association analysis there are three facies that developed in the study area. First, delta plain facies consisting of fluvial sands, silt and clay. Second, delta front facies consisting of beach ridge sands ...

Rudarsko-geološko-naftni zbornik, 2020

Area development deals with optimal land use and the reduction of the risk of geological disaster... more Area development deals with optimal land use and the reduction of the risk of geological disasters. The coastal area of South Bali is prone to land settlement hazards. In order to mitigate the risk, it is important to understand the depositional environment of the area related to its bearing capacity and geological hazard risks. The aim of this research is to understand the subsurface depositional environment and quantifying its bearing capacity. Quantitative modeling was carried out to obtain the sediment-bearing capacity of the Pendungan area in Bali, Indonesia. The methods used in this research were the observation of borehole cores, the identification of the cone penetration test (CPTu) curves pattern, the sediment index property test, the soil strength laboratory, and bearing capacity analysis. Based on lithologic association, the CPTu curve pattern, and grain size analysis, there are three facies developing in the study area with different bearing capacity values. Generally, b...

IOP Conference Series: Earth and Environmental Science, 2020

The historical landslide data in GIS (Geographic Information System) environment is valuable to e... more The historical landslide data in GIS (Geographic Information System) environment is valuable to estimate pattern in landslides distribution and frequency, which are useful for landslide hazard analysis and mitigation. By using the landslide reports released officially by The National Agency for Disaster Management (BNPB), those non-spatial data need to be converted into the spatial ones. The reports primarily contain location, date of event, impact and triggering factor. This study is exploring Google Maps which is a web mapping service to process the historical landslide data of Indonesia. By preparing historical landslide data in the form of spreadsheet, Google Maps directly can change the whole data into a custom map ‘landslide distribution map’. The attribute can be edited, the map can change interactively, and vice versa. The appearance of the custom map can be styled by a certain column so its statistical information comes up. A landslide distribution map produced in Google Ma...

Penyimpanan akhir limbah radioaktif bertujuan untuk menjaga agar zat radioaktif tidak terlepas ke... more Penyimpanan akhir limbah radioaktif bertujuan untuk menjaga agar zat radioaktif tidak terlepas ke lingkungan sampai aktivitas zat tersebut turun ke level yang aman. Konsep penyimpanan akhir limbah radioaktif (LRA) yang akan dikembangkan di area Pusat Penelitian Ilmu Pengetahuan dan Teknologi (Puspiptek), Serpong adalah penyimpanan akhir limbah radioaktif dekat permukaan ( near surface disposal - NSD). NSD berdasarkan kedalaman terbagi dua macam yaitu NSD dekat permukaan dan NSD kedalaman menengah. Konsep NSD pada penelitian ini adalah NSD kedalaman menengah, yaitu antara 30–300 meter. Pada saat konstruksi NSD di kedalaman menengah dibutuhkan pekerjaan ekskavasi bawah permukaan atau pembuatan terowongan. Analisis tegangan in-situ dan deformasi bawah permukaan dilakukan untuk mengetahui besaran dan distribusi tegangan yang terbentuk di dalam tanah/batuan serta deformasi yang terjadi pada saat dilakukan ekskavasi bawah permukaan. Berdasarkan analisis diketahui nilai tegangan dan sebara...

Indonesia is one of the world’s most natural disaster-prone country from landslides. These landsl... more Indonesia is one of the world’s most natural disaster-prone country from landslides. These landslides mostly occur at areas having steep to very steep slopes, intensive weathering processes and high to very high rainfall intensity. Generally, debris flows referred to mudflows or lahars. These types of landslide are common type of fast-moving landslide. In this regard, the occurrence of several landslides followed by the debris flow often make a lot of casualties and very terrible destructions in some areas of Java Island, Indonesia. For example, Jemblung Landslide on December 12, 2014 has 139 causalities. Accordingly, some debris flow modelling have been conducted to determine run-out distribution characteristics of debris materials at the depositional areas. The concept of debris flow modeling is based on the equations of momentum, continuation, riverbed deformation and erosion/deposition and riverbed shearing stress. From the modeling of Pasir Panjang landslide case, the viscosity...

Relationship between rainfall pattern, threshold and landslide process have widely developed. How... more Relationship between rainfall pattern, threshold and landslide process have widely developed. However, real-time observation in real landslide event is time consuming and has high degree of uncertainty. Therefore more analysis is usually developed in regional data scale with correlation between regional rainfall dataset and landslide inventory mapping. In this study, another approach is developed with a physical laboratory scale model. This research developed correlation between simulated rainfall pattern with mechanism and process of landslide. Rainfall with specific intensity and duration are given in residual volcanic soil in laboratory scale. Rainfall threshold observed between laboratory and regional model is highly correlated. There also occurred clear relationships between intensity, duration, antecedent rainfall, with rainfall’s initiation and morphology.

The researches on landslides caused by earthquakes seem to get widely attention lately. Earthquak... more The researches on landslides caused by earthquakes seem to get widely attention lately. Earthquake induced landslides generally have characteristics of large numbers or scale, and wide distribution, so these will cause very terrible effects of losses and destructions. There are four earthquakes induced landslides happened in wide area of Indonesia over the last five years with magnitude more than 6 (M > 6.0), which are Tasikmalaya earthquake (2009), Padang Pariaman earthquake (2009), Sigi earthquake (2012), and Central Aceh earthquake (2013). In this occasion the investigation of earthquake induced landslides in Indonesia was performed from some opened documents and literatures. The features were mainly described based on geomorphology, geological properties, magnitude and source of the earthquake. In addition, the uses of aerial photography and remote sensing processing have been applied to be further analyzed. It revealed that these all generally occurred in unstable areas havi...

A landslide in Mukapayung Village, West Bandung Regency, West Java happened on March 25th, 2013 b... more A landslide in Mukapayung Village, West Bandung Regency, West Java happened on March 25th, 2013 by a changing from initial slide to flow mechanisms. Landslide occurred in tropical mountainous region with weathered volcanic materials derived from tuffs and volcanic breccias. This landslide destroyed 11 houses, killed around 17 people and damaged more than 2 Ha rice fields. Historically, a large landslide located in proximity to this area, i.e. Kidang Pananjung Village, was determined to cause greater damage and loss in 2004 with likely similar mechanisms and materials. In order to better understanding to the Mukapayung landslide, preliminary simulations used DEM based on 1 : 25,000 scales of Geospatial Information Agency topography map were carried out. The results showed that materials flowed through an existing flow track into valley within nearby depositional area and it was inconsistent comparing with actual field conditions. A subsequent simulation was conducted with considering...

Natural Hazards, 2011

The goal of this paper is to assess the landslide susceptibility of a hilly area in the Subcarpat... more The goal of this paper is to assess the landslide susceptibility of a hilly area in the Subcarpathian sector of the Prahova Valley, using the weight of evidence statistical method. This method aims to reduce the multitude of landslide-related conditions to a pattern of a few discrete predictive variables. The method is based on the decision of which state is more likely to occur grounded on the presence or absence of a predictive variable and the occurrence of an event (e.g., landslide) within a pixel. Based on the chi-square test and the Pearson correlation applied on the data, the selected conditionally independent variables in this study were as follows: slope gradient, slope aspect, and land use. Weights calculated individually for the three themes were added to produce a probability estimate of the area. The predictive power of the map was tested on the basis of a split sample of landslides that were not used in the modeling process. The fact that a great percent of the declivitous surfaces are susceptible to landslides shows the dominant manner of the evolution of the Subcarpathian slopes, the acceleration or deceleration of the process being influenced by the land use.

. Darma Dam is located in the Village, District Kadugede, Kuningan regency, West Java, is a combi... more . Darma Dam is located in the Village, District Kadugede, Kuningan regency, West Java, is a combination of the type heap dam (rockfill) and homogeneous soil deposits. Darma dam holds the potential disaster similar to the disaster Situ Gintung, Tangerang, which claimed hundreds of people. In fact, its potential is much more dangerous, if not anticipated. Darma dam is located in the hills, so that there is automatic in the area underneath paddies, plantations, and residential population that stretches from Kab. Kuningan, Kab. Cirebon, to Brebes, Central Java. Seeing the potential dangers posed by Darma then it should dam was monitored his activities as one of the main ways to mitigate catastrophic collapse of the dam. One of the main methods used to monitor the activity of the dam is deformation using methods that are used to monitor the deformation of the dam is with a survey method GPS (Global Positioning System). GPS surveys have been carried out for dam deformation monitoring Darm...

IOP Conference Series: Earth and Environmental Science, 2021

Rongga District is located on West Bandung Regency, West Java, which is prone to landslide disast... more Rongga District is located on West Bandung Regency, West Java, which is prone to landslide disaster. Morphological conditions in the form of steep hills become the one of landslide controlling factors. There are many landslide occurrences happen in this area, such as Nyomplong, Cibitung Village on March 23, 2020. The incident was triggered by heavy rain and strong winds. This area was chosen to assess the landslide susceptibility using the Weight of Evidence (WoE) Method. WoE is probabilistic bivariate method which connecting parameters causes landslide against distribution of landslide in research area. Landslide data which generated from direct observation in the field and satellite imagery morphology are 572 landslide events. The data is divided into two groups, the analysis data set (70%) and the validation data set (30%). The parameters used in the analysis are land use, slope, slope direction, curvature, elevation, rainfall, lithology, NDWI, NDVI, distance from road, distance ...

Hampir beberapa minggu yang lalu, tepatnya tanggal 12 November 2004, gempabumi yang sangat dahsya... more Hampir beberapa minggu yang lalu, tepatnya tanggal 12 November 2004, gempabumi yang sangat dahsyat telah menjenguk sebagian wilayah tanah air, yaitu di Alor, Nusa Tenggara Timur (NTT). Peristiwa ini juga telah terekam sebagai suatu malapetaka (bencana) yang cukup besar, dengan tidak kurang dari 31 korban jiwa meninggal dunia, ratusan korban lainnya luka-luka, dan kerugian material yang tentunya tidak sedikit pun tak lepas dari ganasnya gempa bumi ini. Di bagian lain wilayah tanah air, serangkaian kejadian longsoran seakan hadir tiada kunjung hentinya, seperti di Sawahlunto (Sumatra Barat), Cililin (Jawa Barat), Pasaman (Sumatra Barat), Cianjur (Jawa Barat), Gowa (Sulawesi Selatan), Purworejo (Jawa Tengah), yang juga telah banyak merenggut korban jiwa manusia dan merusak berbagai infrastruktur yang ada. Sementara itu, gunungapi-gunungapi nan anggun pun telah dengan cukup setianya memberikan berbagai isyarat akan ancaman keganasan dan kedasyatan kemarahannya. Ini semua dengan jelas memperlihatkan fakta bahwa kita semua baik secara sadar maupun tidak sadar telah menempatkan diri kita hidup berada di wilayah yang penuh akan potensi bencana alam.