Three students from the Department of Civil and Environmental Engineering (DTSL) of the Faculty of Engineering, Universitas Indonesia (FTUI) presented solutions in the form of appropriate methods of reinforcing and repairing soil for geotechnical problems related to the construction of a coal stockyard project in Tanjung Enim, South Sumatra. The three students are Juan Fidel Ferdani (Civil Engineering 2019), Rubby Anistia Prasetyo (Civil Engineering 2020), and Bayu Dewanto (Civil Engineering 2020).
Along with the large amount of coal production in the Tanjung Enim Mining Unit (UPTE), it is necessary to have a place to store coal in the form of a coal stockyard. A coal stockyard is a place of accumulation or material that is stacked to be taken, processed, and utilized. In addition, the coal stockyard functions as a coal blending process to prepare the required quality. This makes coal stockyards have a very important role in maintaining production flow and ensuring the availability of coal supply.
However, another problem arises from the UPTE area which is swamp land. This can be a problem considering that swamp soil is a type of soft soil with a high level of water content. This situation can then cause geotechnical problems that generally occur in the form of land subsidence. Therefore, geotechnical works in the form of soil reinforcement and soil improvement are required. This aims to support the construction of a coal stockyard to match the existing soil conditions in the Tanjung Enim area, South Sumatra through the construction of a coal stockyard.
“The geotechnical problem found in Tanjung Enim is the presence of soft soil that is so deep that it requires a long consolidation process to achieve settlement according to standards. Because of this, the project required attention to slope stability. To determine the appropriate method for soil reinforcement and improvement, an identification process was carried out of the existing conditions and construction needs in the design of the coal stockyard in Tanjung Enim,” Juan explained.
The review process was carried out with detailed research of the existing conditions and design needs. Soil reinforcement and improvement are carried out by preloading methods for the consolidation process, the use of Prefabricated Vertical Drains (PVD) to accelerate the consolidation process, and the use of Geosynthetics for several aspects of soil reinforcement and improvement in the embankment soil section.
“The planning flow of the coal stockyard project included several steps. The initial stage involved land preparation and installation of the first layer of woven geotextile type VT 600/50. Then, the first embankment with a height of three meters was constructed. After that, layer 2 woven geotextile type VT 600/50 was installed, followed by the installation of OVD type AD 250 and PHD,” Rubby explained.
The next step was the installation of layer 1 non-woven geotextile type CP 10 and a 100 mm layer of geomembrane type Solmax. A vacuum system that included a prezometer, inclinometer, settlement plate, and vacuum plate was also installed. The vacuum pumping process was carried out, and the vacuum system was continuously monitored.
“In the final stage, the installation of layer 2 non-woven geotextile type CP 10 was carried out before starting the final backfill. The coal stockyard project work schedule includes several stages, including preparation, earthwork, backfilling, PVD and PHD installation, geotextile and geomembrane installation, vacuum system, and finishing work,” concluded Bayu.
The Dean of FTUI, Prof. Dr. Heri Hermansyah, S.T., M.Eng., expressed his hope for the solution proposed by FTUI students, “The solution provided in geotechnical problems in the form of soil reinforcement and improvement in the coal stockyard construction project in Tanjung Enim provided by DTSL FTUI students is a form of solution ideas that should be appreciated. Hopefully, the right method proposed can be a real solution to the geotechnical problems that exist in Tanjung Enim.”
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Bureau of Public Communication
Faculty of Engineering, Universitas Indonesia