7th International Conference on Advances in Civil Engineering (ICACE2024) 12-14 December 2024 CUET, Chattogram, Bangladesh https://icace2024.cuet.ac.bd COMPARATIVE PERFORMANCE ANALYSIS OF RECTANGULAR, DIAMOND AND HEXAGONAL SHAPE GEOCELLS IN REINFORCING MEDIUM DENSE TO VERY LOOSE SOILS USING FEM Shantunu Chowdhury* 1 , Anindya Baidya 2 , Sanjoy Das 3 1 Graduate Student, Chittagong University of Engineering and Technology, Bangladesh, e-mail: chowdhuryshantunu51@gmail.com 2 Graduate Student, Chittagong University of Engineering and Technology, Bangladesh, e-mail: anindya.baidya2015@gmail.com 3 Assistant Professor, Chittagong University of Engineering and Technology, Bangladesh, e-mail: sanjoy07@cuet.ac.bd *Shantunu Chowdhury Abstract This study examines the effects of geocell geometry on the settlement behaviour of sandy soils reinforced with HDPE (High-Density Polyethylene) geocells. Rectangular, diamond, and hexagonal geocell shapes were simulated in Abaqus and applied to three soil density types: medium dense, loose, and very loose soils. To maintain consistency in the analysis three type of geocell were designed with height ratio(H/B) as 1, depth ratio (u/B) as 0.1 and pocket ratio as 0.8. The factors for improvement based on settlement measurements at 10% and 15% (s/B%) indicated that hexagonal geocells are the strongest in improving the stability of the soil, closely followed by diamond-shaped geocells. This indicates that hexagonal and diamond arrangements of cellular structures, under uniaxial and biaxial compressive loads, facilitated a prompt transfer and distribution of loads within the structure as a whole and restricted settlement more effectively than the rectangular shape. Higher number of load distribution points on hexagonal and diamond geocells were attributed to their observed superiority by allowing for more confinement, more effective stabilization of soil than being larger in size and spreading the applied stresses evenly. On the other hand, rectangular geocells with fewer intersection points have a relatively low confinement effect which reduces the aiding of load bearing capacity. Again, the results also show that medium dense soils exhibit the highest improvement factor for optimal balance between soil particle interlocking and geocell reinforcement. In looser soils, however, a steeper increase in the improvement factor was noted, reflecting a greater relative benefit from geocell stabilization as it counters the inherent instability of low-density soil structures. This study underscores the potential of HDPE geocells, particularly in hexagonal and diamond configurations, for enhancing soil reinforcement. Such advancements hold promise for sustainable infrastructure development, offering a reliable approach to improving ground stability in various geotechnical applications. Keywords HDPE geocell reinforcement, Geocell shape comparison, Load bearing enhancement, Density dependent soil reinforcement, FEM. 1. Introduction The need for sturdy and dependable foundations on loose or poor soils has grown more urgent in light of the quickly progressing infrastructural development. Conventional foundation support techniques frequently fall short of the demands of expanding construction projects. Thus, in these adverse conditions, innovative ground improvement techniques are needed to enhance the bearing capacity and minimize the settlements. Application of HDPE geocell one potential soil reinforcing technology is the geocell, which are three-dimensional cellular confinement systems a wound in a rollout that is intended to confine infill materials within geocell framework for soil stabilization and improvement [1, 2] .These give confinement to the sub soil which enhances the mechanical properties of soil & prevent lateral movement as a result the load distribution takes place and distortion is reduced [2, 3] . Compared to traditional ground improvement techniques, geocells—a type of geosynthetic—offer a range of advantages, including ease of installation, low cost, and the potential for low environmental impact [2]. Geocells can be constructed from a multitude of materials, but HDPE is particularly used due to its robustness, pliability, and durability. HDPE (high-density polyethylene) geocells provide a three-dimensional cellular confining system that can limit lateral pressure and is therefore ideal for use in various geotechnical applications ranging from energy-dissipating structures (e.g., retaining walls, roads, etc.) to foundation elements for buildings