Search Results (28)

Optimizing the structural stability of foundations is challenging in modern geotechnical engineering. This study investigated the mechanism of geocell-reinforced foundations through discrete element modeling based on transparent soil model tests. A three-dimensional particle flow code (PFC^3D) model was developed to investigate the micromechanical soil–geocell interactions in both unreinforced and geocell-reinforced foundations under strip loading. Particle displacement, contact force distribution, and structural deformation within the foundation system were analyzed to quantify the performance of geocell reinforcement. The results show that geocell inclusion enhances structural performance by 2.1 times compared to an unreinforced foundation, increasing the bearing capacity from 60.6 to 126.8 kPa at a defined bearing capacity criterion. The geocell walls act as rigid physical boundaries that microscopically intercept the lateral migration and horizontal extrusion of soil particles. The kinematic trajectories of soil particles beneath the loading plate are forced into a downward realignment, decreasing the displacement vector rotation angle from 42° in the unreinforced soil to 27° in the reinforced soil and effectively mitigating the heave of adjacent surfaces. Furthermore, the quasi-rigid three-dimensional network completely interrupts the continuous steep contact force chains inherent in unreinforced foundations. Concentrated vertical stresses are converted into horizontal components through interfacial friction and mechanical interlocking, resulting in the lateral redistribution of the applied load by a distance of approximately 0.06 m. The geocell–soil composite considered as a flexible raft foundation extends load dispersion and reduces average subsoil pressure. A coupled tension and compression stress state in the horizontal plane is developed within the geocell structure. Forces are channeled along rigid paths by elevated bending moments and stress concentrations at the cell junctions. These findings provide micromechanical insights into the performance of geocell-reinforced-foundation systems. Full article

This study investigates the thermo-mechanical response of geocell-reinforced concrete pavements through scaled model tests and three-dimensional finite element analyses. Static, thermal, traffic, and coupled temperature–loading tests were conducted to clarify the deformation evolution, strain distribution, and damage-related response of the reinforced structure. The results show that, under static loading, pavement settlement evolves through three stages, namely initial compaction, plastic development, and stable strengthening, indicating progressive mobilization of geocell confinement. Under thermal loading, slab strain exhibits pronounced spatial and temporal non-uniformity, and the slab center is identified as the thermally sensitive zone. Under coupled temperature–loading conditions, both strain and settlement show a non-monotonic response near 1.1–1.3 kN, suggesting a potential damage-initiation range. Post-test crack observations further provide direct qualitative evidence that local cracking damage occurred in the slab under representative loading conditions. Under traffic loading, permanent deformation accumulates with load repetitions and is highly sensitive to load amplitude, indicating a load-sensitive transition in cumulative deformation behavior rather than a definitive fatigue threshold. Numerical results further show that geocell reinforcement reduces central settlement by 17.4% relative to plain concrete pavement and by 7.6% relative to doweled pavement, while producing a smoother deflection basin and a more uniform stress distribution. Parametric analyses indicate that the optimum geocell height is approximately one-third of the slab thickness; beyond this range, the marginal reinforcement benefit decreases. Overall, the results demonstrate that geocell reinforcement can effectively improve load transfer, deformation compatibility, and thermo-mechanical stability of concrete pavements under the investigated conditions. Full article

This study performs a comprehensive experimental analysis of the dynamic response of geocell-reinforced sandy subgrades exposed to traffic-induced loading. A series of laboratory tests were performed using a custom-manufactured loading apparatus capable of creating monitored dynamic waveforms representative of vehicular traffic. A steel strip footing was assigned on both unreinforced and geocell-reinforced sandy beds to evaluate the implementation of the reinforcement in attenuating transmitted vertical stresses and surface settlements. The influence of key parameters, among which were load amplitude (0.5 and 1.0 tons), loading frequency (0.5, 1.0, and 2.0 Hz), and relative density of sand (30% loose and 60% medium), was systematically examined. The applied dynamic loading was based on a force-controlled sinusoidal waveform with constant amplitudes and frequencies, which corresponded to low-frequency harmonic cyclic loading in the case of traffic-induced quasi-static effects. Therefore, the experimental results indicate that geocell reinforcement reduces the transmitted vertical dynamic stress by up to 45% and reduces surface settlement by about 60% compared to unreinforced sand. However, the heightening efficiency decreases with loading frequency, the amplitude of the load, and the relative sand density. Thus, the findings are important in highlighting the capacity of geocell systems to enhance the longevity and efficiency of sand substrates when the systems are subjected to low-frequency harmonic cyclical loading conditions pertaining to traffic-induced quasi-static influences. Full article

The large-scale generation and disposal of fly ash pose significant environmental concerns, highlighting the need for its sustainable reuse in geotechnical applications. This study investigates the performance of fly ash blended with polypropylene fiber as an infill material in geocell-reinforced sand beds to enhance bearing capacity and reduce settlement. Plate load tests were conducted in the laboratory by varying geocell mattress height, cement content, fiber content, and curing period. The results showed that polypropylene fibers improved the shear strength of the fly ash mix. Increasing the geocell mattress height from 0.5B to 1B enhanced the ultimate bearing pressure of a sand bed by 3.4×. At a mattress height of 1B, an improvement factor of 13.18 was achieved at a settlement (s/B) of 12.5%, and this improvement is attributed to confinement provided by the geocell because of enhanced load distribution. Fly ash mix with 6% polypropylene fiber and 5% cement yielded an ultimate bearing pressure of 460 kPa after 3 days of curing, which was 6.9× higher than that of an unreinforced sand bed. These findings demonstrate that fiber-reinforced fly ash is a sustainable and efficient infill material for geocell mattresses, offering both environmental benefits and improved geotechnical performance. Full article

Visibility on roads can be poor during winters owing to snowstorms and other factors. Optical devices, including Light Detection and Ranging devices, are ineffective under whiteout conditions. Moreover, buildings, trees, and other obstacles reduce the accuracy of the Global Positioning System. Therefore, we investigate vehicle navigation using an Ultrahigh Frequency Radio Frequency Identification (RFID) system. This study extends a previously developed RFID-based navigation system for paved roads to unpaved roads. Unpaved roads, particularly those in mountainous or forested areas, can become unstable because of weather conditions and present unique challenges regarding the stability of RFID tags. We use geocells to provide road stability and maintain the RFID tags at the ideal position and attitude. We insert RFID tags into polyvinyl chloride pipe holders and attach them to geocells. We also use the vehicle heading angle from the inertial navigation system (INS). In some areas, the INS is disturbed and shows incorrect direction. We utilize the RFID tag reading history to improve vehicle positioning accuracy by compensating for errors in the INS. Applying this correction reduces the average deviation from the lane center. Driving experiments are conducted on a straight unpaved road, and good results are obtained. These results validate the robustness of the proposed vehicle navigation system, which combines an RFID system with a geocell, providing insights into its successful implementation on unpaved roads. Full article

The purpose of this study is to evaluate the perceptions of the educational community regarding the use of recycled materials in sustainable road infrastructure. To this end, an 11-question survey was administered to students, teachers, and administrators at the La Sagrada Familia Technical Educational Institution in Ibagué, Colombia. The survey assessed their attitudes, awareness, and acceptance of sustainable materials in dimensions such as knowledge of sustainability, perception of recycled materials, and willingness to recommend sustainable practices. As part of the study, a 17 m-long vehicle platform was constructed using geocells made from recycled tires. This practical implementation served both as a demonstration of the potential of recycled materials in road infrastructure and as an educational tool to engage the community in sustainable practices. The construction process included awareness campaigns to educate participants on the environmental and functional benefits of using recycled materials. Preliminary results indicate a significant shift in perception after participants were educated on the benefits of recycled materials. Teachers and administrators showed high levels of acceptance, with 96.6% of teachers reporting improved perceptions. Students, while enthusiastic, showed more varied levels of satisfaction, reflecting their varied exposure to sustainability concepts. This study underscores the critical role of educational projects in fostering awareness and acceptance of sustainable solutions. It highlights the potential of initiatives such as geocells made of recycled tires to integrate practical applications with educational efforts, thereby advancing the adoption of circular economy principles and promoting long-term social benefits in infrastructure development. Full article

This paper develops an analytical model to calculate the ultimate bearing capacity of the integrated plug high-strength geocell (IPGC)-reinforced foundation under a square footing. The high strength and stiffness of the geocell wall and the typical failure of the integrated plug-in joint tearing were considered. The ultimate bearing capacity of the IPGC-reinforced foundation was calculated in two separate parts. The ultimate bearing capacity of an unreinforced foundation was calculated using the modified Terzaghi equation. The increased bearing capacity of the IPGC was calculated as the function of the tearing force of the geocell wall, the height and the diameter of a geocell, the empirical static earth pressure coefficient, and the vertical additional stress coefficient under uniformly distributed rectangular loading. The results showed that the maximum error between the experimental and the theoretical results is less than 18%. The ultimate bearing capacity of IPGC-reinforced foundations decreases with larger geocell diameters. When the diameter of the geocell exceeds 1.8 times the foundation width, the confinement effect of IPGC becomes negligible. The findings of this study offer a robust analytical equation for predicting IPGC-reinforced foundations, along with valuable insights into the efficacy of IPGC reinforcement in enhancing foundation stability. Full article

In this study, the performance of unpaved road sections over soft clay soil geosynthetic-reinforced and stabilized with rock fill layer was evaluated using repeated plate loading tests. A total of 10 field tests were carried out using a circular model rigid plate with a diameter of 0.30 m. The parameters investigated included the location and type of geosynthetics and loading conditions (number of loading cycle and traffic loading condition). Based on the test results, the least deformation was observed in the rockfill section. The geocell placed at a depth of one-third thickness of the granular fill layer from the top showed improved performance and was more effective as compared with other geosynthetic reinforcements. However, for granular fill geosynthetic-reinforced or stabilized with rock fill layer, the results demonstrate an improvement in the rutting performance of the pavement and the definite trend of increasing reloading elastic modulus, depending on the traffic loading situation. It has been also observed that the use of geocell or geogrid reinforcement in granular fill layer or more rigid rockfill layer provides an important increase in the modulus improvement ratio (MIR) by at least 36%, 45% and 60% compared to the granular fill section, respectively. Full article

The challenge of maintaining ride quality and serviceability in flexible pavements built over expansive soil deposits remains a critical concern for transportation agencies. These expansive subgrades exhibit swell-shrink behavior in response to moisture fluctuations, leading to differential heaving and subsequent costly maintenance. This paper explores the effectiveness of a Hybrid Geosynthetic Reinforcement System (HGRS)—a composite of geocell and geogrid—as a targeted mitigation strategy for differential heaving induced by expansive soils. A large-scale box test was designed to simulate a flexible pavement section, consisting solely of a base course layer and the underlying expansive subgrade. Four test conditions were investigated: an unreinforced control, a geocell-reinforced section, a geogrid-reinforced section, and an HGRS-reinforced section. Vertical displacements on the surface of the base course layer were longitudinally monitored and compared against the control. The results reveal that the use of geosynthetic reinforcements, and HGRS in particular, significantly mitigates both maximum surficial heave and differential swelling. Among the systems tested, flexible pavements featuring HGRS demonstrated the most effective performance in alleviating the challenges posed by expansive soil deposits. Full article

Geocells are widely applied in numerous infrastructure constructions, like heavy-haul railways and ports. The mechanical tearing behavior of a geocell strip is crucial to the stability of the geocell-reinforced soil structures. At present, extensive studies have been conducted on the tensile characteristics of geocell strips, while limited research has been performed to investigate the post-damage mechanical tearing behavior of geocell strips. Meanwhile, there is also a lack of research on the comparison of performance of strips before and after damage. In this paper, a series of trapezoidal tearing tests were performed on high-density polyethylene (HDPE) and polyester (PET) geocell strips. The tearing test results and failure mode of trapezoidal specimens with a slit were investigated, and the effect of the slit on the strength and deformation characteristics of the specimen were discussed by introducing the “damage ratio of tearing force (R_TF)” and “damage ratio of tearing displacement (R_TD)”. In addition, the mechanical tearing behavior of HDPE and PET trapezoidal specimens was also compared. The test results indicated that the failure mode of HDPE and PET specimens subjected to tearing force was ductile and brittle failure. The strength and deformation characteristics of post-damage HDPE and PET trapezoidal specimens decreased. The slit had a significant impact on the tearing displacement of HDPE and PET specimens, especially the post-peak tearing displacement. The post-peak tearing displacement of HDPE was 10.99 times that of PET. The peak tearing force of the HDPE specimen without the slit was about 1.61 times that of specimen with the slit. Before local tearing, the peak tearing force of the PET specimen without the slit was about 3.27 times that of the specimen with the slit. The strength damage to the HDPE and PET geocell strips caused by the slit was 38.0%, and 69.46%. The impact of the slit on the tearing force of the PET specimen was greater than that of the HDPE, and was 1.82 times for the HDPE. This study can enhance our understanding of the mechanical tearing behavior of the geocell strip after damage and develop effective mitigation measures. Full article

Geocells, which are polymeric interconnected cells filled with soil, provide excellent support to loads through all-round confinement and a beam effect; hence, they are extensively used in various geotechnical applications such as embankments, foundations, pavements, slopes, railways, and reinforced earth (RE) walls. Although the applications of geocells are studied extensively, their geometric and parametric evolution as a stable support to heavy loads receive less attention. The current versatile configuration of geocells has geometrically evolved after accounting for all the factors that give them optimum reinforcement efficiency. This paper presents a state-of-the-art review of the geometric evolution of geocells in the context of transportation geotechnical engineering. Effects of shape, size, stiffness, and surface roughness of geocells, and properties of infill and native soils on the performance of geocells are compiled from the literature to get important design insights. The application of geocells in pavements is discussed, concluding that geocells improve the cyclic load carrying capacity and resilient characteristics of pavement, reduce rut depths, and increase traffic benefit ratio (TBR). Hence, geocells can be a sustainable alternative to natural materials in transportation infrastructure, with the added advantages of reduced carbon footprint and maintenance costs. Full article

Geocells are commonly adopted in various engineering constructions, such as railways and ports. Currently, the reinforcement effects and mechanisms of geocells in engineering is being widely studied, while limited studies have been performed on the mechanical behavior of geocell strips. Uncertainties regarding their performance have impeded the wide application of geocells in engineering fields. In this paper, a series of tensile tests and trapezoidal tests were performed on high-density polyethylene (HDPE) geocell strips. The effects regarding specimen shape, specimen width, and welding junction on the tensile mechanical behavior of HDPE geocell strips were investigated. Additionally, the results of the tensile test and trapezoidal test were also compared. The test results showed that the tensile strength of a HDPE geocell strip was less affected by the specimen shape and specimen width, within 5%. However, the elongation of HDPE strips was sensitive to the specimen shape, and the difference between type I dumbbell and type II rectangular was up to 38%. The effect of the welding junction on the HDPE strip cannot be ignored, the strength retention rate of the welding junction was 76.3%. The curve of the trapezoidal test was similar to that of the tensile test, and the force of trapezoidal test was 0.87 times that of the tensile test. The test results can provide a reference for the testing of strip performance and structural design. Full article

The construction of integral bridges is one of the most effective methods to reduce bridges’ construction and in-service costs. However, there are associated geotechnical problems with their abutments backfill due to the integrated abutments. The main goal of this study is to evaluate and quantify the benefits of geogrid reinforcement for reducing the backfill’s geotechnical problems. For this purpose, using small-scale physical modeling, the benefits of geogrid reinforcing of the backfill of an integral abutment bridge subjected to cyclic movements are evaluated. The results are then compared with a previous study performed on unreinforced backfill and two types of geocells. In this study, 120 loading cycles are applied to geogrid-reinforced soil to simulate the cyclic loadings on integral abutment backfill due to seasonal abutment displacement. The horizontal reaction load at the top of the wall, changes in pressure behind the wall, and deformation in backfill soil are measured during the test. Then the results are discussed in terms of equivalent peak lateral soil coefficient (K_peak), lateral earth pressure coefficient (K*), and normalized settlement behind the wall (S_g/H). The derived lateral soil coefficients and settlement behind the abutment show that geogrid substantially reduces pressure and settlements after 120 cyclic loads. Based on the results, K_peak and K* of the geogrid-reinforced backfill decrease by up to 36%, and S_g/H behind the wall decreases by 62%. In addition, the comparison of the results for geogrid with two geocell types shows that geogrid is more efficient in terms of lateral soil coefficients. Full article

A series of triaxial compression tests with different confining pressures were conducted for gravels, road surface milling materials, and surface–base milling mixtures to investigate the stress–strain relationships of these three kinds of materials. On the basis of the analysis of the test results, the strength and the deformation of the geocell-reinforced surface milling materials and the geocell-encased surface–base milling mixtures were predicted and compared with those of the gravels via the constitutive model of geocell–soil composites. The effects of the geocell pocket size, tensile stiffness, and the peak internal frictional angle on the stress–strain responses of the geocell-reinforced surface–base milling mixtures were examined. Moreover, by employing the finite element strength reduction technique, stability analysis was conducted on the geocell-reinforced retaining wall with the surface–base milling mixtures to investigate the factor of safety and the failure mechanism of the structure. The study results indicated that the surface milling materials exhibited strain hardening, while the gravels and the surface–base milling mixtures exhibited strain softening. The surface milling materials displayed evident shear contraction characteristics, whereas the gravels and surface–base milling mixtures first displayed shear contraction and later dilatancy features. In addition, the strength of the geocell-reinforced surface milling materials is smaller than that of the gravels, but the strength of the geocell-encased surface–base milling mixtures is larger than that of the gravels. Thus, the geocell-reinforced surface–base milling mixtures can be used to replace the gravels in engineering practices. Additionally, the size of the sliding wedge and the factor of safety of the retaining walls increase significantly with reductions in the geocell pocket size. Full article

In desert regions, aeolian sand is abundant, but it is not suitable to be used directly as the upper roadbed filler for highways. Generally, gravelly soil is mined around the desert as upper roadbed fill, resulting in high engineering expenses for road construction in the desert hinterland. Geocells have a significant reinforcing effect on aeolian sand. However, in the completed desert highway, the dynamic performance of geocell-reinforced aeolian sand as an upper layer of roadbed fill has not been studied. Using a field test method, the dynamic performance of geocell-reinforced aeolian sand as an upper roadbed fill is examined. The results show that the majority of the frequency distribution of road vibration is within 30 Hz. In the horizontal direction, the actual vibration amplitude decay on the side of geocell-reinforced aeolian sand is slower but smoother than on the side of gravelly soils. In vibration velocity, the work area depth of the geocell-reinforced aeolian sand side of the roadbed is less than that of the gravelly soil side. The maximum difference can reach 0.55 m. As far as vibration velocity is concerned, the 30 cm gravelly soils can be substituted with 15 cm geocell-reinforced aeolian sands as the upper roadbed. In summary, the dynamic attenuation characteristics of geocell-reinforced aeolian sand are superior to gravelly soils. The research results provide a reference for the design of the desert highway subgrade. Full article