Journal of Engineering and Technological Sciences
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Evaluation of Lateral and Axial Deformation for Earth Pressure Balance (EPB) Tunnel Construction Using 3 Dimension Finite Element Method
Get PDFMass Rapid Transit Jakarta (MRTJ) phase 1 tunnel construction using the earth pressure balance method has been completed and surface settlement and lateral displacement data according to elevation and inclinometer readings has been collected to evaluate the effect of tunnel’s construction on surrounding infrastructure. Soil stratification along the research area, defined according to boring logs and soil parameters for the hardening soil model (HSM) and the soft soil model (SSM), was determined by optimization of stress-strain curve fitting between CU triaxial test, consolidation test and soil test models in the Plaxis 3D software. Evaluation of the result of surface settlement measurements using an automatic digital level combined with geodetic GPS for elevation and position control points showed that the displacement behavior was affected by vehicle load and stiffness of the pavement. Lateral displacement measurements using inclinometers give a more accurate result since they are placed on the soil and external influences are smaller than surface settlement measurement. The result of 3D finite element modeling showed that surface settlement and lateral displacement during TBM construction can be predicted using HSM with 2% contraction. SSM and the closed-form solutions of Loganathan and Poulos are unable to provide a good result compared to the actual displacement from measurements
Metal-supported SOFC Fabricated by Tape Casting and Its Characterization: A Study of the Co-sintering Process
Get PDFMetal-supported SOFC consists of metallic and ceramic multilayers. Since the cell has to be flat, interaction between the layers that results in a flat sintered layer needs to be studied. The method used here was changing the starting materials through several experiments. Here, we highlight the effects of pore former in metal slurry on the sintered half-cell multilayer of a 430L metallic support, an NiO-8YSZ anode, and an 8YSZ electrolyte. The results show that by changing the amount of pore former in the 430L metal slurry changed the sinterability of the metal layer. This change of the sinterability of the metal support affected the final warpage state of the cell. This study aid in explaining the sintering phenomena between layers of metal-supported SOFCs
Simulation of Rainwater Harvesting Potential to Satisfy Domestic Water Demand Based on Observed Precipitation Data in Jakarta
Get PDFJakarta as the most populous urban center of Indonesia has a major problem related to clean water availability for the domestic needs of its residents, who mostly depend on the extraction of groundwater. The rooftop rainwater harvesting (RRWH) system is a solution to reduce the use of groundwater to satisfy domestic water needs. This study used demographic data and precipitation observation data from the rain gauge network in Jakarta to simulate the water supply from rainwater harvesting from 2010 to 2019 in each municipality. Three simulations were carried out to calculate the percentage of domestic water demand (DS) satisfied by RRWH based on the proportion of residential areas installed with RRWH (RA). The results showed that an RA value of 0.2 produced the lowest DS (approximately 11% to 18.7%), while an RA value of 0.3 produced a higher DS (approximately 16.3% to 28%). An RA value of 0.4 resulted in a DS of around 21.8% to 37.4%. Overall, the RRWH system could provide up to 30% of domestic water demand on average, with South Jakarta having the highest fulfillment of water needs with an average of 28% based on the three simulations, while Central Jakarta had the lowest with 16.4%
Characteristics of Rainfall-Induced Slope Instability in Cisokan Region, Indonesia
Get PDFA 25.5 km long access road has been constructed in a hilly area in Cisokan region. Several slope instabilities occurred during the rainy season, particularly at the end of heavy rainfall. A comprehensive study was performed to understand the characteristics of rainfall-induced slope instability. The study consisted of field observation, analyses of field and laboratory test data, and numerical analyses. The study revealed that in general there were two categories of slopes with instability characteristics: (i) slopes with a significant groundwater level increase during rainfall; (ii) slopes with an insignificant groundwater level increase during rainfall. In the first category, the slope instability was caused by a loss of matric suction and eventually the pore-water pressure, uw became positive as indicated by an increase of the groundwater level. In the second category, the slope instability was caused by a loss of matric suction without a rise in pore-water pressure, uw, to a positive magnitude. Two empirical curves of slope stability were developed as a preliminary guidance to assess slope stability during rainfall in the region
