TABLE 4 - uploaded by Craig H Benson
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The objective of the present study was to evaluate the mechanical properties of tire chips and soil-tire chip mixtures relevant to geosynthetic-reinforced earthworks. Tests were conducted to evaluate shear strength and pull-out capacity with a woven geotextile and two geogrids. Soil-tire chip mixtures made with clean sand and sandy silt were tested...
Contexts in source publication
Context 1
... required embedded lengths based on external and in- ternal stability requirements (sliding, overturning, failure plane, and pull-out) are summarized in Table 4. The required embedded lengths for pull-out shown in column 7 of Table 4 correspond to the length extending beyond the failure plane. ...
Context 2
... required embedded lengths based on external and in- ternal stability requirements (sliding, overturning, failure plane, and pull-out) are summarized in Table 4. The required embedded lengths for pull-out shown in column 7 of Table 4 correspond to the length extending beyond the failure plane. For all walls, the total required length for pull-out (length-to- failure plane plus the length beyond to develop pull-out ca- pacity) was less than the distance to the failure plane at the top of the wall (Table 4, column 6). ...
Context 3
... required embedded lengths for pull-out shown in column 7 of Table 4 correspond to the length extending beyond the failure plane. For all walls, the total required length for pull-out (length-to- failure plane plus the length beyond to develop pull-out ca- pacity) was less than the distance to the failure plane at the top of the wall (Table 4, column 6). ...
Context 4
... controlling length (Table 4, column 8) is the maximum of the lengths required for the different stability considerations (Le., lengths in columns 4-6), and it increases with wall height. Comparison of controlling lengths for a 15-m high wall indicates that similar lengths are required for the geotextile and geogrid (=8-9 m), and the addition of tire chips reduces the controlling length only in sandy silt backfill (to 6 m) be- cause addition of tire chips increases the cohesion intercept of the sandy silt. ...
Context 5
... pull-out capacity of the geosynthetic layer, which is used in the external and internal stability calculations, affects the number of geosynthetic layers needed in a geosynthetic- reinforced wall (Fig. 8 and Table 4). That is, fewer layers are needed when the pull-out capacity is higher. ...
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Citations
... The incorporation of recycled PET strips into soil has been found to affect the normalshear stress characteristics of the soil, as shown in Figure 16 [124]. The presence of PET strips can enhance the soil's shear resistance, leading to increased shear strength and improved stability [125]. In the study of Al-Taie, Al-Obaidi and Alzuhairi [87], the influence of incorporating 2% recycled PET fibers on the shear stress of poorly graded soil was investigated. ...
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... C i represents the ratio of the average interface strength to the internal shear strength of the soil and is a key metric for quantifying the reinforcement effectiveness in pullout tests. According to Bergado and Chai 49 and Tatlisoz, Edil, and Benson, 50 the C i value can be calculated as follows: ...
The study aims to assess the impact of geogrid reinforcement on embankments over soft soil subjected to strip loading through experimental and finite element method-based numerical analyses. Various factors, including footing location, geogrid depth, length, and the number of layers, were systematically varied to evaluate their influences on the bearing capacity of strip footing on top of slope. The study shows that an increase of up to 75 % in bearing capacity was observed for the reinforced slopes with the use of multiple geogrid layers at optimum depths and lengths. Further, the optimum number of geogrid layers is contingent upon the footing location. Moreover, the effectiveness of single basal reinforcement for different footing locations and dimensions was explored, and an improvement of up to 34.5 % was observed in bearing capacity. Further, the results indicate that effective improvement in bearing capacity through basal reinforcement is only possible when the failure zone penetrates the interface between the embankment and base soil. Otherwise, the use of multiple layers of reinforcement at shallower depths is proved to be more effective.
... In order to define the interaction efficiency at soil-geosynthetic reinforcement interface for design of reinforced soil structures, an interaction coefficient (C i ) or interaction efficiency has been proposed in earlier studies [44][45][46][47]. Interaction coefficient (C i ) depends on normal stress, interface characteristics, and material properties in c-ϕ soils. ...
Landfill mining is one of the efficient and economical methods to manage legacy municipal solid waste; wherein, significant proportion of the mined waste consists of landfill mined soil like fraction (LMSF). The presence of organic matter, heavy metals, material heterogeneity and wide variability in properties has restricted the utilization of LMSF as material source. In this context, the present study explores the application of geosynthetic reinforcement for performance improvement of LMSF as a fill material. LMSF is initially characterized to obtain its engineering properties. Further, large direct shear tests are carried out to quantify the shear strength parameters at LMSF-geogrid and LMSF-geotextile interface. An interaction coefficient of about 0.6 and 0.58 has been obtained for LMSF-geogrid and LMSF-geotextile interfaces, respectively. Moreover, plate load tests have been conducted on LMSF-geogrid and LMSF-geotextile reinforced fill at various depth of embedment (ranging from 0.25B to 1.5B) and varying areal extent of reinforcement (ranging from 1 to 5B). An enhanced bearing capacity ratio of 2.1 and 1.8 has been obtained for geotextile (at 0.25B depth) and geogrid (at 0.75B depth) reinforced LMSF, respectively; that is comparable with reinforced soils adopted for fill applications. The study makes a novel effort to conceptualize and quantify the stress–strain response at geosynthetic-LMSF interface, and demonstrates the beneficial application of geosynthetics reinforcement of LMSF with enhanced bearing capacity ratio and settlement reduction ratio. The study findings reflect the potential of geosynthetic-reinforced LMSF as a sustainable fill material, a small step towards achieving United Nations sustainable goals.
Graphical Abstract
... Direct shear test and pullout tests have been widely used to assess the interaction behavior between reinforcements and backfill material for evaluating the internal stability of MSE walls [18][19][20][21][22][23][24][25][26]. Sliding and pullout are the two critical failure modes taken into account in the design of reinforced earth structures [27,28]. ...
... Due to the emergence of non-conventional fill materials, it is crucial to thoroughly assess the interaction between the reinforcement and the fill material prior to its usage. Several studies have been conducted in the past to investigate the interaction of reinforcement with different types of non-conventional fill materials [19,[37][38][39][40]. In a study conducted by Bandyopadhyay et al. [37], the pullout resistance capacity of geogrid in crumb rubber-sand mixture was examined. ...
The growing industrialism has led to the generation of unmanageable waste, which is usually dumped in landfills. Utilizing these materials in reinforced earth structures will not only help in large-scale recycling of the materials but also restrict the overutilization of geo-materials. The aim of the present study is to assess the interaction of biaxial geogrid with two different solid waste materials namely, steel slag (SS) and construction and demolition waste (CDW) and compare its performance with the conventional backfill material, sand. To achieve this, direct shear tests and pullout tests were conducted at various normal stress levels ranging from 25 to 200 kPa. The direct shear results revealed that both steel slag and CDW exhibits higher shear strength compared to sand. Similarly, the pullout test results indicated that the pullout resistance of the geogrid is higher in steel slag and CDW than in sand. The pullout resistance factor (\({F}^{*}\)) was evaluated to quantify the interaction of the geogrid with backfills. \({F}^{*}\) values were found to be greater than 1 at lower normal stress (25 kPa), and less than 1 at higher normal stress (200 kPa), indicating a stronger interaction at lower normal stresses. According to interaction coefficient ratio (ICR) values, the interaction of the geogrid with steel slag and CDW at 25 kPa normal stress was 38% and 33% higher, respectively, than that with sand. Furthermore, an artificial neural network (ANN) model was developed using data from the current study as well as data gathered from previous studies to predict the pullout resistance of geogrids in a wide range of geomaterials. An excellent prediction capability was observed with coefficient of determination (R2) value more than 0.9.
... The interface between the behavior of geosynthetics as well as the soil can be described by the coefficient of soil-reinforcement friction [4,[21][22][23]. The following equation yields the interface's shear strength coefficient. ...
... • It can be seen that the installation of geosynthetics reduces the apparent cohesion of the materials from 22 .25° for G1, G2, G3, and GT, respectively. ...
Geosynthetics are being used to strengthen road pavement. Geosynthetic inclusions improve pavement carrying capacity, maintenance costs, highway service life, reflective cracks, and undesirable large lateral and vertical deformations. The primary purpose of this research is to determine the effectiveness of geosynthetics (geogrids and geotextiles) in stabilizing the subgrade and reinforcing the base course layers in unpaved test sections. Determine the mechanical interaction of subgrade soils (clay and sand) and aggregate road base layers (subbase) with and without reinforcement. Compute the shear strength parameters (cohesion, friction angle, and interface coefficient factor). Therefore, Large-scale direct shear experiments in the laboratory were performed on subbase-subgrade materials with and without geosynthetics, under the applying normal of stresses (25, 50, 75, and 100) kPa, indicating the quantity overburden the pressure in paving. The present research uses a large-scale direct shear apparatus with an up square box (200 mm×200 mm×100 mm) and a bottom rectangular box (200 mm×250 mm×100 mm). A direct shear test was implemented by manufacturing this equipment. The results obtained from experiments showed that biaxial geogrid G1 has the best behavior for both (subbase-clay) and (subbase-sand) and has an interface shear coefficient factor more significant than unity and equal to 1.05 and 1.02, respectively.
... These different phenomena could cause significant clogging at the intra-rib spaces, resulting in an efficiency higher than 1 in all the clay-ribbed continuum surface interfaces at all the normal stresses. Similar efficiency values were also observed by Tatlisoz and Benson [60] and Abu-farsakh et al. [1] in compacted clay and rough continuum interfaces. These studies established that interface efficiency values greater than 1 indicate that there is an efficient bond between the soil and the continuum material. ...
The effect of the shape of snakeskin-inspired patterns on the shear behaviour of soil-continuum interfaces was investigated for their potential applications in geotechnical engineering. For this purpose, continuum surfaces with ribs inspired from the ventral scales of three different snakes, each with three intra-rib spacings, were fabricated using a 3D printer and their shear behaviour with sand and clay soils was tested under three normal stresses. The results of the interface direct shear tests show that snakeskin-inspired ribs mobilise higher interface shear resistance than an unpatterned surface in sand and clay and considerable inhomogeneous deformations at the interface. The type of soil, the applied normal stress, the shape of the ribs and the direction of shearing were found to be factors that influence and dictate the shear behaviour of the different ribbed interfaces. The snakeskin-inspired ribs mobilised considerable frictional anisotropy owing to the difference in their shapes in the shearing directions. The failure envelopes of the ribbed interfaces were found to follow a nonlinear trend and were described using a power curve. The efficiency of the sand-ribbed interfaces decreased with an increase in normal stress, while a reverse phenomenon was observed in clays, indicating that the interaction mechanism of the ribs is different in different soils for the direct shear test conditions. Digital Image Correlation technique on the sand interfaces revealed that a shear zone of thickness 11 times D50 of sand was mobilised at the interface, further confirming the inhomogeneous deformation at the interfaces.
... In order to evaluate the effectiveness of the modifications, the ratio of "maximum reinforced shear strengths to maximum unreinforced shear strengths" have been determined and defined as "Interaction Coefficient, " also used by Abdi et al. [2] and Tatlisoz et al. [54] as follow: ...
Geogrids are widely used for soil reinforcement, justifying the necessity to comprehend their interaction with soil for safe and economic design of reinforced soil structures. As contribution of transverse rib resistance to soil–geogrid interaction in direct shear mode is very low, current research has been conducted to evaluate possible impact of modifying transverse member thickness (height) on interactions. Modified geogrids with three different transverse rib thicknesses perpendicular to load direction and different aperture sizes were generated by 3D printing technology and interactions at soil–geogrid interface investigated using large-scale direct shear apparatus. Poorly graded sand and normal pressures of 25, 50 and 75 kPa have been utilized in the investigation. Test results show maximum 22% improvement in overall shear strength at interface through greater transverse rib resistance mobilization using the modified geogrid with the thickest ribs (i.e. 6 mm). Enhancements showed to be directly related to the increase in rib thickness and inversely associated to aperture size. The highest and the lowest improvements in shear strengths at interface were correspondingly achieved by samples reinforced with 10 × 10 × 6 mm (length × width × rib thickness) and 40 × 40 × 2 mm geogrids.
... An interaction coefficient greater than 0.5 indicates a good bond between fill material and reinforcement (Goodhue et al., 2001;Pant et al., 2019a;Tatlisoz et al., 1998). The Chinese code for the Design of Highway Reinforced Earth Engineering (JTJ015, 1991) also recommends that the minimum C i values in sand or gravel-like material should be more than 0.4. ...
The study presents the geoenvironmental and geotechnical characterization of MSW incineration bottom ash (IBA) and examines its reuse as structural fill in reinforced soil structures (RSS). The suitability of reuse has been assessed with regard to international regulatory standards. The prime focus of the work remains on evaluating the pullout response of geosynthetic reinforcements through IBA fill to determine the interaction coefficient, which has never been addressed in the literature. The economic viability of using IBA instead of locally available river sand for a 12 m high MSE wall is also established.
The column leaching test results confirm that IBA can be utilized in RSS with suitable design measures. The geotechnical investigation shows that IBA is a well-graded, non-plastic lightweight material with adequate drainage and high shear strength. The pullout test results demonstrate that the interaction coefficient of polymeric strips and geogrid in IBA (0.73–1.53 and 0.79–1.91, respectively) is comparable or higher to materials conventionally used as structural fill in RSS, indicating adequate bondage between IBA and geosynthetic reinforcement. Further, it is estimated that using IBA as a substitute for available river sand in the vicinity can potentially reduce the overall RSS project cost by 15–20%, even if IBA has to be transported 50 km away from the project site.
... The researchers reported a reduction in the seismic load transferred to the wall due to the presence of tire chips. Furthermore, significant numbers of literature are available on the interaction behavior of geosynthetics with the tire-sand mixtures [36][37][38][39]. Researchers reported that geosynthetics shows higher interlocking properties with tire-sand mixtures. ...
The applicability of crumb rubber mixed with sand as alternative fill material in mechanically stabilized earth
(MSE) walls is investigated in the current study. Shaking table tests have been conducted to analyze the dynamic
response of model geogrid reinforced earth walls subjected to three different base input motions. Eight different
sand-crumb rubber mixture combinations were used as backfill. The outcomes of this study provide quantitative
results on how base excitation amplitudes could influence the seismic behavior of the MSE walls in the presence
of sand-rubber backfill. The results have been analyzed in terms of deformation and rotation of the wall, settlement
of backfill, acceleration amplification, and earth pressure response. Wall displacement and backfill
settlement was found to reduce with the addition of rubber in the sand. The maximum displacement at the top of
the wall was found to reduce by 45% at a rubber content of 30% for high peak ground acceleration (PGA) input
motion. Two-wedge failure was observed with the failure envelope inclined at an angle of 49◦ from the vertical.
Apart from this, the strain in the geogrid was decreased with an increase in the rubber content. Hence, the rubber
content of 30% mixed with sand can be considered an optimum percentage to control the dynamic performance
of MSE walls. In the end, a cost-benefit analysis was conducted, and it was found that using rubber as a partial
substitute for sand backfill reduces the overall cost of the project. This research will also promote the use of
recyclable rubber as a construction material in highway construction.
... The interaction coefficient values greater than 1 indicate that there is a proper bond between the soil and geosynthetics, and the interface strength between the soil and reinforcement is higher than the soil shear strength (Tatlisoz et al. 1998) [68]. The values lower than 0.5 indicate either a weak bond between the soil and the geosynthetic layer or the collapse of the geosynthetic layer (Tatlisoz et al. 1998;Ghazavi and Roustaei 2013) [68,69]. ...
... The interaction coefficient values greater than 1 indicate that there is a proper bond between the soil and geosynthetics, and the interface strength between the soil and reinforcement is higher than the soil shear strength (Tatlisoz et al. 1998) [68]. The values lower than 0.5 indicate either a weak bond between the soil and the geosynthetic layer or the collapse of the geosynthetic layer (Tatlisoz et al. 1998;Ghazavi and Roustaei 2013) [68,69]. ...
... The interaction coefficient values greater than 1 indicate that there is a proper bond between the soil and geosynthetics, and the interface strength between the soil and reinforcement is higher than the soil shear strength (Tatlisoz et al. 1998) [68]. The values lower than 0.5 indicate either a weak bond between the soil and the geosynthetic layer or the collapse of the geosynthetic layer (Tatlisoz et al. 1998;Ghazavi and Roustaei 2013) [68,69]. Therefore, the values obtained in this study are in the acceptable range for the geogrid and geotextile interfaces with soil. ...
Access to suitable materials for the construction of reinforced earth structures in some areas may challenge the profitable feasibility of the project. In such areas, replacing the common embankment materials with materials containing numerous fine grains available on-site can lead to significant cost savings. Providing solutions for the use of this type of material has always been the focus of researchers. Finding suitable reinforcement and correct evaluation of shear strength parameters of the soil-reinforcement interface are among these solutions. To investigate the effects of geosynthetics, soils fine grains, and water content, the shear strengths of the clayey sand soils-reinforcements interface were compared, using large-scale direct shear tests. The results revealed that the strength curve of the interface was near to the soil strength curve in soil with 5% fine grains; however, the reinforcement in the saturated state for large shearing displacements led to a higher shear strength than the soil strength. For the soil containing 20% and 40% fine grains with optimum water content, the use of geogrids and geotextiles dropped the shear strengths of the interfaces to values lower than the soil strength for small shearing displacements. In the saturated state, the shear strengths of both reinforcement interfaces with soil were vastly higher than the internal soil strength. The results revealed that soils containing fine grains could be perfectly reinforced using geogrids and geotextiles. However, the effect of using geogrids in sandy soils with lower fine grain contents was greater than the geotextile. Conversely, in soils containing a high percentage of fine grains, especially those that have high water content, the geotextile as reinforcement was more efficient than the geogrid.
