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This research investigates the innovative application of 3D printing technology in the production of geomembranes for laboratory-scale geotechnical experiments. Commonly, geotechnical research relies on the results of model testing. However, due to the high costs and complexity involved, full-scale model testing is rarely carried out. Geomembranes are essential components in various civil engineering projects, particularly in environmental containment and hydraulic barrier systems. In this research, the potential of 3D printing as an innovative method for producing geomembranes is carried out. Using a 3D printer, this research aims to prepare geosynthetic models with accurate geometric scales and tensile properties suitable for laboratory testing. A comparison was made between HDPE geomembranes and 3D printed geomembranes, to highlight their performance in a geotechnical laboratory environment. The research results show that 3D printed geomembranes show potential for applications in geotechnical research.

Pavement deterioration can be caused by expansive road subgrade material. Swelling properties are one of the problems on expansive soils. The swelling properties can be decreased by stabilization using additives. The potential of using chitosan biopolymer for soil improvement is attractive due to environmental friendliness and sustainability. This research was conducted to determine the effect of chitosan biopolymer from shrimp shell waste on the Atterberg Limits of expansive soil. This test can be used as an initial assessment of soil strength and stiffness parameters. The Atterberg Limits test was carried out by mixing chitosan biopolymer with a ratio of 0.05%; 0.10%; 0.15%; and 0.20% to the dry weight of the expansive soil. The study’s results showed that adding chitosan biopolymer with a ratio of 0.1% was the most effective in reducing the plasticity index by up to 67% and increase in the shrinkage limit value which is greater than 12%, making the degree of expansion non-severely. The use of chitosan biopolymer is also expected for soil pollution control and remediation.

Peat soil is formed through the accumulation of undecomposed plant organic matter, resulting in a high fiber content that leads to poor physical properties and low shear strength. Consequently, peat soil is identified as problematic and detrimental in infrastructure construction. One proposed method to improve its physical properties and enhance shear strength is biological soil stabilization through biotechnology, with bioaugmentation as an environmentally friendly alternative. The objective of this research is to accelerating the decomposition of peat fiber by Pseudomonas taiwanensis bacteria, thereby accelerating soil compaction and improving its physical properties and shear strength. The subject of this research is fibrous peat soil in Bereng Bengkel Village, Palangkaraya, Central Kalimantan. From the experimental results, it was found that the addition of 15% Pseudomonas taiwanensis bacteria to fibrous peat can significantly improve the physical properties and shear strength. Thus, Pseudomonas taiwanensis bacteria can be used as an environmentally friendly alternative to improve the geotechnical properties of fibrous peat.

Landfill materials composed of weak soil are closely related to stability problems. To minimise this problem, various stabilisation techniques are often used, one of which is the addition of polyacrylamide anionic polymer (APAM). In this paper, soil behaviour before and after adding APAM in the West Bandung area, Indonesia, has been analysed. It has been done with different variables by considering the landfill's geometry and the soil material's properties. Several models were analysed to determine the slope height and angle that are safe for soil stabilisation. The modelling was done using the finite element method based on the soil hardening criteria model and Mohr-Coulomb. The analysis results show that with the increase in height and slope, the safety factor (FS) decreases, and the deformation increases. Conversely, if the height and slope decrease, the FS increases, and the deformation decreases. It is observed that the soil with the highest percentage of APAM (1%) has produced the highest shear strength parameters and the lowest deformation. This study found that weak soil treated with APAM can be used as a backfill material, but the potential for collapse is more significant. [ABSTRACT FROM AUTHOR]

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Soft clay soil is a concern in geotechnical engineering due to its low strength and high compressibility. Soil improvement with stabilization techniques is an interesting topic in the field of geotechnical engineering and pavements. Nanomaterials and biogeotechnicalbased soil improvement are in high demand, as is the case with the objective of this research which is to determine the effect of the addition of nano lime, nano silica, and chitosan biopolymers to soft clay soil on its mechanical properties. The ratio of additives in this study was taken based on previous research, namely 2% nano lime, 4% nano silica, and 0.1% chitosan biopolymer from shrimp shell waste. Specimen variations consist of initial soil, soil mixed with biopolymers, soil mixed with nanomaterials, and soil mixed with biopolymers and nanomaterials. The mixing method in this study was carried out by mixing the additives according to the percentage of the initial soil dry weight, then water was added to the mixture. Compaction and unconfined compression strength (UCS) tests were conducted on each specimen. The results show that mixing soil with nanomaterials and chitosan provides advantages in mechanical properties. This can be seen from the increase in the UCS value which is up to 11 times that of the initial soil and the increase in the maximum dry density value. Soil stabilization using nanomaterials and chitosan biopolymers has a good impact on the environment. Reducing the ratio of lime in soil stabilization on a project scale can reduce CO2 emissions during production and the use of chitosan biopolymer additives can reduce marine biota waste, especially invertebrates. [ABSTRACT FROM AUTHOR]

Copyright of Rudarsko-Geolosko-Naftni Zbornik is the property of Faculty of Mining, Geology & Petroleum Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)