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An internal explosion may cause severe damage to an underground and surface ground structures. The intensity of the blast plays a substantial role in the damage to the structures, the configuration of the structure, material properties, and geometry of materials. There are several ways for a structure to be protect against blast loads. A tunnel could be protected employing the protective layer, directly located on the top of the structure. The influence of utilizing a protective layer, made of geofoam could appease the adverse effects of an internal explosion and decline vibrations when it comes to the surface ground. The modeling procedure used the coupled Eulerian–Lagrangian in Abaqus/Explicit. Lagrangian elements have been used for modeling soil and reinforced tunnel and trinitrotoluene as Eulerian elements. Drucker–Prager plasticity, Holmquist–Johnson and Johnson–Cook plasticity models were simulated for the stress–strain response of soil, concrete, and reinforcement, respectively. In addition, Jones–Wilkins–Lee equation of state used for the pressure-volume relation of TNT. As the results show, while explosion waves scatter inside tunnel and penetrate among top layers of soil, soil and lining without a protective layer experienced severe deformation and blast waves influenced surface ground structures negatively. Indeed, the more charge weight, the more deformation on tunnel lining and structures. It is observed that increasing geofoam thickness worked up to a certain thickness and semi-circular geofoam section on top of the structure fulfilled expectations. [ABSTRACT FROM AUTHOR]

A landslide triggered by heavy rainfall occurred in the Al-Husainiyyah Junior High School area on April 26th, 2023. The landslide damaged the nearby access roads, the existing retaining wall, and a futsal court threatening the safety of the teachers and students in conducting the learning activities that especially require open areas. Thus, this community service aims to provide a cantilever wall design with geofoam as an innovative lightweight backfill material to reinforce the slope and repair the damaged structures. Field surveying and numerical analysis were then conducted to understand the current slope and soil conditions and to analyze the stability of the slope and retaining wall. The results show that a cantilever wall with a total height of 1.8 m supported by a strauss pile row with a diameter of 0.4 m, 4 m in length, and 2.5 m in spacing could increase the stability of the slope.

The lateral pressure exerted by expansive soils on retaining walls constructed with expanded polystyrene geofoam blocks (EXRW-EPS), upon water infiltration to saturation, is crucial for designing these structures. In this study, model tests were employed to examine the behavior of EXRW-EPS subjected to water infiltration, with concurrent monitoring of deformation and lateral pressure. The results showed that the compressive deformation of the expanded polystyrene (EPS) geofoam block facilitated swelling deformations of the backfilled expansive soil, effectively mitigating the lateral pressure experienced by the retaining wall. Upon saturation of the backfilled expansive soil, the total lateral force on the wall decreased by approximately 44% by the EPS geofoam block with a density of 12 kg/m3. A practical method for predicting the lateral pressure on EXRW-EPS upon water infiltration to saturation was developed based on the relationship between the EPS geofoam block and the backfilled expansive soil. The reliability of this method was corroborated by the model test results. Additionally, the effects of the density and thickness of the EPS geofoam block on the lateral pressure of EXRW-EPS were analyzed using the prediction method. • Lateral pressures experienced by expansive soils on retaining walls are effectively reduced by EPS geofoam blocks. • A practical method for predicting lateral pressures upon water infiltration to saturation is proposed. • Effects of EPS geofoam block density and thickness on lateral pressures are analyzed using the proposed method. [ABSTRACT FROM AUTHOR]

The present study focuses on an advanced and accurate characterisation of the compressive behaviour of expanded polystyrene (EPS) geofoam with the aid of imaging techniques. To this end, four types of EPS geofoam with nominal densities varying from 15 kg/m3 to 30 kg/m3 are used. Initially, a detailed physical characterisation is carried out including image-based microstructural quantification (cell size, void fraction, population density), homogeneity using ultrasonic pulse velocity and apparent density. Insights into the compression behaviour of the geofoams, including true strains and failure patterns, are further gathered through full-field strain behaviour in the block using two-dimensional image correlation analysis. For the first time, the effect of nominal densities on the Poisson's ratio of geofoam is also studied through image analysis. The study reveals that compressive response is significantly influenced by homogeneity, which is manifested by the changes in microstructure and apparent density of the geofoam. Furthermore, the image analysis provides insights into the development of failure patterns and strain localisation and their dependency on density, comprehending the geofoam's complex behaviour. Predictions of compressive response based on apparent density and non-destructive tests are developed. The study further recommends safety factors for determining permissible and yield stresses based on statistical analysis. [ABSTRACT FROM AUTHOR]

Geosynthetic engineering has made significant advances during the past decade in the areas of manufacturing and practical applications. As a result, geosynthetics have become essential materials that facilitate construction, better improve short- and long-term performance, and reduce long-term maintenance costs in routine civil engineering projects. Geosynthetics are also being recognized as fundamental to sustainable infrastructure development as they reduce the carbon footprint generated by infrastructure development by minimizing the use of natural construction materials. Creative use of geosynthetics in geo-engineering practices is expected to continue to expand as innovative materials and products are becoming available. In this paper, we begin by discussing issues related to climate change. The sustainable benefits of geosynthetics are then presented by demonstrating the potential of geosynthetics to significantly reduce carbon footprints compared to traditional solutions. Finally, recent geosynthetic technologies have been introduced for use in transportation infrastructure. The pathway forward of the geosynthetic technology is also discussed from the view of sustainable infrastructure development. [ABSTRACT FROM AUTHOR]

Expanded polystyrene (EPS) geofoam is a light and deformable geosynthetic that can reduce the pressure on the pipe by surrounding soil. The protective effect of geofoam bocks protection on the buried pipe under stratum settlement was investigated. The effect of settlement displacement, diameter-thickness ratio, internal pressure, surrounding soil, and EPS thickness on the axial strain and ovalisation of pipe were analyzed. The results show that the axial strain and ovalisation of pipe protected with EPS are smaller than that in soil. With the increase of the pipe diameter-thickness ratio, the axial strain and ovalisation of pipe with or without protection increase. With the increase of internal pressure, the buckling mode of pipe buried in soil changes from collapse to wrinkle gradually, but the ovalisation changes of pipe protected with EPS is small. When the surrounding soil is rock, buckling occurred in the without protection is more obvious. The safety of the pipeline is better with thicker EPS.

Expansion and contraction of bridge decks move integral bridge abutments (IABs) toward and away from the backfill, resulting in high horizontal earth pressures, backfill surface settlements, and abutment toe movements away from the backfill. Geofoam can reduce relative abutment movements to the backfill when the abutment moves toward the backfill due to bridge deck expansion. Geosynthetic reinforcement can improve the stability of the backfill, thus reducing backfill surface settlements when the abutment moves away from the backfill due to bridge deck contraction. Numerical analysis was utilized in this study to investigate mechanisms of geosynthetic reinforcement and geofoam and effects of key parameters, such as the thickness and elastic modulus of geofoam and the length and vertical spacing of geosynthetic reinforcement. Increasing the thickness and/or reducing the elastic modulus of geofoam could reduce maximum horizontal earth pressures in the backfill. However, the effects of geofoam to reduce backfill surface settlements were not significant. In addition, geosynthetic reinforcement reduced surface settlements of the backfill away from the abutment but increased surface settlements of the backfill right behind the abutment. By connecting the front ends of geosynthetic reinforcements with the abutment, settlements of reinforced backfill decreased at the expense of large settlements of unreinforced backfill. Furthermore, geofoam together with geosynthetic reinforcement with wrap-around facing could significantly minimize seasonal temperature change-induced problems for IABs. [ABSTRACT FROM AUTHOR]

In this paper, attenuation potential of expanded polystyrene (EPS) geofoam as the embankment material of cut and cover tunnels during static and dynamic loads was assessed by a series of numerical analyses, verified against experimental study. The geofoam is found to have excellent capabilities to attenuate the static and dynamic loads of the tunnel lining. The layout of the geofoam directly influences its attenuation potential. The efficiency of the geofoam is increased as the level of the acceleration of the input motion increases. The study demonstrates that the geofoam performs well as a protective material for underground tunnels during earthquakes. [ABSTRACT FROM AUTHOR]

Rockfall hazard is a major problem especially in mountainous regions where steep rock slopes are present and the properties of the surficial rock masses are suitable for fragmentation. Highways, railroads, and other infrastructural elements built in the trajectory of the rocks need to be protected. In critical locations that are under constant risk of rockfall hazard, protection galleries can be a good choice for shielding highways, railroads, and other lifelines. In order to reduce the damage induced by rockfalls to an acceptable level, damping and absorption of the impact energy at the collision have a significant importance. Within the scope of this study, displacements, stresses, and strains on a reinforced concrete protection gallery located at the toe of an actual rock slope during rock fall impacts were investigated by numerical analyses performed using RocFall and ABAQUS codes. In the light of analyses results, it is anticipated that the use of expanded polystyrene as a compressive layer on protection galleries can be beneficial to reduce the transmission of the impact forces caused by a rock collision. Impact analyses for a 1000 kg mass were carried out using explicit dynamic analysis module of finite element method-based ABAQUS software. Results indicate that use of EPS geofoam significantly reduces the destructive effect of the rock falls on the reinforced concrete protection galleries. Structural displacements are significantly less when EPS is used as cushion material instead of granular fill. A percentage reduction of 85% is observed in the maximum value of sectional displacements. An approximate reduction of 76% is observed in the maximum values of stress on the protection structure in the vicinity of the impact zone. Results indicate that the use of geofoam compressible layers may protect the structure from taking significant damages therefore increase the useful economic life of the concrete structure. [ABSTRACT FROM AUTHOR]

Expanded Polystyrene (EPS) is commonly used in construction, especially in geotechnical projects, due to its super lightweight and high compressibility. One of the applications of this material is to use it behind the retaining walls to reduce the lateral earth pressures exerted on the wall by the embankment. In this research, two types of EPS in the form of granules and sheets of EPS are used as interface between the embankment and the wall. In order to carry out this research, an instrumented laboratory model of retaining wall has been used and the effect of using these materials as buffer behind retaining wall has been investigated. The assembly includes a 105 28.5 70 cm sand box, a retaining wall model with 28.3 54.2 cm front dimension, a wall-displacement system for driving the wall, and a data acquisition system (data logger). The lateral pressures are measured by eight load cells attached to 8 equally spaced wall sections. The approximate relative density of the backfill sand was 70%. Experiments included cases in which a sheet of EPS-block or stack of small bags filled with granular EPS was used as a buffer between soil and wall. The results of these two cases were compared with the case in which the backfill was the sand alone. After measuring the lateral forces in the at-rest state, the active and passive states were created by displacing the wall away or toward the backfill. The lateral stresses could be measured in any state of displacement. The results showed that the use of EPS behind the retaining wall as an interface material resulted in a significant reduction in lateral pressures. This was due to the very low stiffness of EPS compared to the soil. It was also observed that the use of bags filled with EPS-granules had a greater effect on the reduction of lateral pressures on the retaining wall compared to using sheets of EPS-block.

Expanded Polystyrene (EPS) is used as an inclusion to mitigate stresses acting on tunnels. In this study, the efficiency of utilizing EPS in reducing dynamic loads acting on shallow tunnels was studied. To gauge this, dynamic modulus of elasticity (Ed) and shear modulus (G) of EPS with densities equal to 25, 30, and 35 kg/m3 were characterized based on series of ultrasonic tests, where Ed ranged from 3500 to 6578 kPa, and G ranged from 1535 to 2741 kPa. A correlation was developed between EPS density and damping coefficient, which ranged from 1% to 2.3% based on G and the ultrasonic wave decay. A model was developed for a cut-and-cover tunnel with EPS along its side walls, and a parametric study was conducted using EPS thickness to tunnel depth ratio (tx/h1) varying from 0.05 to 0.20. At tunnel critical sections, normal and bending were reduced by 30% and 46%, respectively.

Differential settlement of bridge abutments has taken place at most bridge abutments on untreated soft ground in Vietnam. The conventional technologies to improve soft ground have often been costly and time-consuming. EPS geofoam, a synthetic and lightweight material, can be used as a fill material to raise the elevation of highway embankments directly on untreat soft ground. However, EPS geofoam has little known as construction materials for transportation structures in Vietnam. This paper attempts to investigate key properties of geofoams made in Vietnam. Several laboratory tests such as compression, water absorption, inflammability, and dissolvent were conducted. The results show that (1) Geofoams made in Vietnam have densities of 12.1 to 34.8 kg/m3 for the EPS-12 to the EPS-34, respectively; (2) qu increases in increasing in densities; (3) Elastic strain is less than 1.5%; (4) Initial modulus varying from 2-10 MPa with density; (5) Poisson ratio around 0.06-0.14; (6) Water absorption by volume from 0.4-3.2%; (7) Geofoam can be quickly burnt. These key properties will indicate suitable geofoam types that can be utilized as highway embankment fills placed on unimproved soft ground directly. [ABSTRACT FROM AUTHOR]

A novel mitigation technique is proposed in this paper to effectively improve the safety and integrity of buried pipelines subjected to ground deformation and to mitigate the detrimental effects of ground deformation on the pipe. This technique involves the installation of special geomaterial blocks (SGBs) adjacent to the pipe. The SGB consisting of multiple layers of hollow plastic boxes placed between layers of high-density expanded polystyrene (EPS) geofoam blocks forms a thick sandwich panel structure, which is oriented such that its orthotropic mechanical property allows the pipe to move laterally without developing significant reactions against the soil. A summary of past mitigation techniques and the method proposed in this study are first presented. Large-scale experimental testing used to assess the beneficial effects of the SGB on the pipe response when subjected to lateral and oblique displacements is then presented, followed by a simplified finite element model proposed to numerically simulate the pipe-SGB-soil interaction under lateral soil displacement. The results confirm that the proposed remediation method can significantly reduce the soil-pipe interaction force. Furthermore, the proposed beam-based numerical model that can be used in engineering design predicts well the lateral load-deformation response of the system. [ABSTRACT FROM AUTHOR]

Nowadays, new materials are widely used for improving the bearing capacity of the soils and geosynthetics include the type of these materials which are utilized in this regard. In addition, the geofoam panel type of geosyntethic materials is useful and an alternative for backfill in retaining wall or pavement layers. The present research mainly aimed to investigate sthe effects of geofoam particles (0.2, 0.5, & 1%) on improving the bearing capacity of the clay-sand mixture. To this end, dune sandy soil (passed from sieve No.30 and residue on sieve No.50) was provided from Shore of the Lake Urmia and mixed with kaoline industrial clay at 15, 30, and 50 percentages. Then, compaction, uniaxial in three loading speed (0.5, 1, & 1.5 mm/min), direct shear (in vertical stresses 1, 2, & 3 kg/cm2), and falling head permeability tests were performed to evaluate the influence of geofoam particles on geotechnical properties of the mixed soil. The results showed that maximum dry density and elastic modulus increased by a 0.5% increase in the geofoam in the soil mixture. Meanwhile, the shear strength of the specimens increased as well. Finally, permeability and the drainage condition improved by adding geofoam to the specimens.

In recent years, special attention has been given to the effects of underground spaces and structures on the seismic response of adjacent ground. Nevertheless, to the best of the authors' knowledge, no method has yet been considered to reduce these effects in technical literature. The present study aims to investigate the role of geofoam as the cover material in cut and cover tunnels on the seismic response of the ground surface. For this purpose, a numerical study was performed using FLAC 2D, a finite difference software, and verified against previous studies. The effects of parameters such as the geofoam type, thickness of the geofoam blocks and interfaces between the blocks, on the ground surface amplification pattern were investigated. Parametric studies demonstrate that the geofoam has a strong potential to attenuate the seismic horizontal movements of the ground surface. As the thickness of the geofoam blocks is decreased, its attenuation ability is increased. It was also determined that the interface between the geofoam blocks plays a key role in the attenuation of the aboveground seismic responses. Based on the results, it was concluded that geofoam is a proper material to attenuate seismic amplifications at the ground surface, induced by underground tunnels. [ABSTRACT FROM AUTHOR]

Applications of geofoam for buried culverts/pipes keep increasing; however, the design of such applications is still challenging due to lack of full-scale studies. Considering practice needs, a full-scale field study was carried out to investigate the effectiveness of different geofoams with different layouts to reduce overburden stresses on deeply buried, large-size culverts. Among the eight test sections, five were installed with two different of geofoams (7.5 and 15 kg/m3) in thicknesses of 300 and 600 mm and the remaining three were built with loose sand, lightly and normally compacted clay, respectively. The acquired data indicated that the geofoam can greatly reduce the overburden stress over the culvert. In general, higher compressibility of geofoam resulted in greater stress transfer but did not cause excessive settlement at the surface due to significant burial depth. However, due to its large span and dome shape, a secondary soil arching formed when the soil over shoulder settled more than that over the crown, which readjusted the stress and resulted in further reduction in the stress at the culvert shoulder but partially compromised the stress reduction at the crown. Such phenomenon shall be appropriately addressed to avoid unexpected damage to buried culverts or pipes. • A full-scale study on geofoam applications on deeply buried culverts was conducted over a nearly 4-year period. • Eight test sections were built as part of a real-world project, which used different geofoams with different configurations. The investigated culverts have a net span of 5 m and overall span of approximately 10 m with a burial depth up to 27 m. • The sections were instrumented and then were monitored during and 30 months after construction. • Sections using loose sand and lightly compacted clay were compared with sections using geofoam. [ABSTRACT FROM AUTHOR]

Ground-borne vibrations are increasing at a rapid rate due to the rise in urban expansion and industrial activities. The current solution to mitigate the unwanted vibrations is limited to the use of single trenches that require unrealistic depths. This paper presents the possibilities of using dual open and infilled trenches to mitigate the vibrations generated due to continuous harmonic motions. Full-scale field tests and comprehensive numerical studies were performed to systematically design dual trenches. The field vibration tests were performed under a wide range of frequencies using the Lazan-type mechanical oscillator. Similarly, numerical studies have been performed using finite element analysis software, PLAXIS 2D. Expanded polystyrene (EPS) geofoams of different densities, bentonite, ceramsite, concrete, and sand-rubber mixture were used as the infill materials. The normalized depths of 0.40 and 0.50 were observed as the optimal values to reach an average amplitude reduction ratio (average ARR) of 0.25 for the dual open and EPS15-infilled trenches, respectively. The isolation efficiency of EPS15-infilled trenches was observed to be 178 % higher compared to the EPS48-infilled trenches. The performance difference between EPS15 and ceramsite-filled dual trenches was observed to be only 4 % in terms of average ARR , the former being superior. [ABSTRACT FROM AUTHOR]

Nowadays new materials for improving bearing capacity of soils are widely used. Kind of new materials used in this regard are geosynthetics. Geofoam panel type of geosyntethic materials is useful and alternative for backfill in retaining wall or pavement layers. Main idea in this research is study geofoam particles effects on improvement bearing capacity of sand. Geofoam particles effects on sand in 0.05, 0.1 and 0.15% percent were considered and sand was considered in granular and angular conditions. In order to evaluating geofoam particles influence in geotechnical properties of sandy soils some laboratory tests such as compaction, direct shear (in vertical stresses 1,2 and 3 kG/cm2) and permeability tests were performed. Results of this study showed that with increasing 0.15% percent geofoam in sandy soils maximum dry density went up, permeability decreased and shear strength of specimens increased. Although, geofoam particles is more effective in angular sandy soil than granular sand.