Today, waste tires pose an environmental challenge due to their considerable land utilization and high disposal costs in landfills. However, recycling waste tires could significantly alleviate this issue. This study employed waste tires for SOIL REINFORCEMENT using two different configurations: the waste tire-cell (WT-cell) and the waste tire-grid (WT-grid), which serve as cellular and planar structures, respectively. A series of laboratory plate loading model tests were conducted to analyze the pressure-settlement behavior of a square plate on both reinforced and unreinforced sand, thereby evaluating the effectiveness of this approach. The study investigated the effects of many parameters, such as the depth of the first REINFORCEMENT layer, the number of the REINFORCEMENT layer, interlayer spacing, and the relative density of the foundation SOIL. The results indicate that using waste tires in a cellular structure (WT-cell) is more efficacious than the planar (WT-grid) in augmenting bearing capacity and reducing settlement. A single layer of WT-cell REINFORCEMENT in loose sand sufficiently enhanced the bearing capacity by 270% and decreased the settlement by 70% compared to unreinforced sand, while the corresponding values for WT-grid REINFORCEMENT were 184% and 46%, respectively. This enhancement was achieved by using an optimal initial layer depth of 0.2B and relative density of foundation SOIL of 40%. The impact of REINFORCEMENT is more noticeable when the sand has a lower relative density. On the whole, the results clearly indicate that using waste tires is an effective option for enhancing SOIL behavior, particularly in light of sustainability considerations.

Successful use of geosynthetics is ensured in a given geotechnical application, as it is not only compatible, but also effective in improving the SOIL properties when appropriately placed. This study investigates the behavior of unreinforced and reinforced sandy SOIL with nonwoven geotextile using CBR tests. The SOIL used, has poor CBR value due to its low compaction and moisture percent. In a series of tests, Geotextile is placed in various depths from the top of samples. The effect of thickness of dense layer (with 97% compaction) on the soft subgrade is also investigated, and the results are compared with reinforced condition. To study the effect of embedment depth of REINFORCEMENT, the geotextile layer is placed in depths of 1, 1.5, 2, 3, 4, 6 and 8 cm from the top of the sample. Furthermore, a comparison between reinforced samples with one layer and two layers of geotextile is done. The results of the CBR tests demonstrate clearly considerable amount of increase in CBR value of SOIL with geotextile REINFORCEMENT. It is also shown that the maximum increase in CBR value is obtained when one layer of geotextile is placed at depth of 1.5 cm. The rate of increase in CBR value was reduced with increase in the placement depth of REINFORCEMENT layer. The thicker dense layer leads to more increase in CBR. In the same density and thickness of the replaced SOIL layer, the highest increase in the CBR value was achieved when the sample was reinforced by two layers of geotextile. To achieve a specified design CBR value, using less depth of replaced SOIL layer in the reinforced subgrade is possible as compared with unreinforced subgrade. For example, using a depth of 1.5 cm and 3 cm of replaced SOIL, CBR value equaling 6 is achieved for reinforced and unreinforced subgrades, respectively. Although the replacement of compacted SOIL layer or the use of REINFORCEMENT layer could increase the bearing capacity, achieving a certain capacity needs to consider the details of economic issues and performance limits.

Background and Aim: SOIL improvement using plant roots has been considered by many researchers in order to strengthen SOIL mass in terms of environmental protection and natural resources. The effect of plant root system on SOIL resilience is a function of the biotechnical properties of roots But due to the complex interactions between SOIL and plant, the impact of root reclamation on SOILs remains a challenge. This study investigates the effect of alfalfa root density on SOIL consolidation in Pazannan region in Khuzestan province Methods: In this study, for the first time, the effect of alfalfa root system was investigated on SOIL resilience in greenhouse conditions. SOIL samples taken from the study area after a period of 5 months under greenhouse cultivation, 3 rootless SOIL samples and 12 SOIL samples with different root densities were tested for direct cutting to measure the shear strength of SOIL composition and roots And the parameters of internal friction angle and adhesion of root-reinforced SOIL were obtained and compared with rootless SOIL samples. Results: In general, the density and number of roots has been reduced with increasing depth, and also the root density index decreases with the depth increases. Using these results and direct cutting tests was calculated the amount of armament. The presence of roots has created a significant resistance to SOIL shear strength, which has been affected by increasing the amount of SOIL adhesion. In contrast, the internal friction angle of reinforced SOIL decreases with respect to the rootless SOIL and has the opposite behavior of the adhesion factor. And its changes are much less than the changes of the adhesion factor. Therefore, it can be known that increasing the shear strength of SOIL reinforced with alfalfa root is equivalent to increasing adhesion. Conclusions: The results of this study show that there is a direct relationship between root density index and SOIL shear strength. The highest and lowest REINFORCEMENT rates for 28 and 5% density index were 87. 5% and 7. 5% increase in SOIL adhesion, respectively and there has been a maximum reduction in internal friction angle relative to rootless SOIL of 5. 5%. This study showed that there is a decrease in the relationship between depth and root density index, depth and strength of REINFORCEMENT as biotechnological characteristics of alfalfa species.

Introduction Recently, several studies on buried pipelines have been conducted to determine their uplift behavior as a function of burial depth, type of SOIL, and degree of compaction, using mathematical, numerical and experimental modeling. One of the geosynthetics applications is the construction of a reinforced SOIL foundation to increase the bearing capacity of shallow spread footings. Recently, a new REINFORCEMENT element to improve the bearing capacity of SOILs has been introduced and numerically studied by Hatef et al. The main idea behind the new system is adding anchors to ordinary geogrid. This system has been named as Grid-Anchor (it is not a trade name yet). In this system, a foundation that is supported by the SOIL reinforced with Grid-Anchor is used; the anchors are made from 10×10×10 mm cubic elements. The obtained results indicate that the Grid-Anchor system of reinforcing can increase the bearing capacity 2. 74 times greater than that for ordinary geogrid and 4. 43 times greater than for non-reinforced sand...

Strengthening of poor and improper SOILs, in order to be utilized in civil engineering projects, for fabricating a SOIL with ideal engineering properties, is called stabilization and REINFORCEMENT. SOIL stabilization is used for various purposes such as prevention of surface erosion, improvement of poor subgrades, controlling of shifting SOILs, rehabilitation of base layers and retrieving of old paths. Today, because of weaknesses such as poor strength and long duration for curing with common stabilizers (lime and cement), the attitude for finding new materials which can improve these deficiencies has increased. In this research, a sandy SOIL, a petrochemical material called epoxy resin (as stabilizer), and also a fiber (as SOIL reinforcing agent) were used to evaluate their effects on SOIL resistance-parameters. The behavior of stabilized SOIL in compression and shear was determined in this project. Results of the tests revealed that compression and tensile strengths of stabilized SOIL with epoxy resin were increased significantly; while the strengths of the sandy SOIL without epoxy were too weak. By addition of fiber to the SOIL samples, the SOIL compression strength was not increased; whereas, it has profound effect to promote tensile strength. Also, SOIL samples containing fiber showed more deformation. This means that they absorb more energy under loading to reach the rupture stage.

Two effective parameters in determining the length of REINFORCEMENTs in the reinforced SOIL slopes are, the one, the length of REINFORCEMENT located in the active zone till to the location of failure surface and the second, the length of REINFORCEMENT located after the failure surface. Generally, the first one is calculated based on the angle of failure wedge by Rankin method. In this method the effect of REINFORCEMENT on the location of failure surface is ignored, while the presence of REINFORCEMENT is effective. In order to assess the location of the failure suface, the horizontal slice method based on Spencer assumption is used. In this method, slippery mass with the presence of reinforces is divided into a number of horizontal slices parallel to REINFORCEMENT direction. Inter-slice forces are computed by using Spencer basic rules. Earthquake load is affected on the center of each slice by horizontal and vertical pseudo-static coefficients. In the presented method, unlike the other existing methods, all of the critical slip surfaces are examined and are reinforced. In this paper, Genetic Algorithm (GA) optimization method is used to optimize the objective function for the produced non-circular slip surface of each horizontal for the safety factor of one. By comparing the results of Genetic Algorithm optimization approach introduced in this research with the results of the other investigators for the same geometry, material properties and loadings of the slopes it is indicated that the introduced and utilized method is more critical for the estimation of the length of REINFORCEMENTs and the design of REINFORCEMENTs with the proposed method is more reliable.

The interaction parameters between SOIL and REINFORCEMENT at their interface play a critical role in influencing the mechanical behavior of reinforced SOIL systems. Interaction parameters between SOIL and REINFORCEMENT influence reinforced SOIL behavior mechanically. In this research, the effect of the size of SOIL grains and the stiffness of the REINFORCEMENT on the pull-out resistance of the REINFORCEMENT from the SOIL has been investigated in a laboratory. The pullout resistance of three types of REINFORCEMENTs with different stiffness in three types of SOIL with different grain sizes has been investigated. Pull-out tests have been performed at three stress levels of 50, 100, and 150 kPa. To investigate this issue and determine an evaluation for the stiffness of the REINFORCEMENT, a device has been built to measure the penetration of solid SOIL grains in the REINFORCEMENT. The results of the tests show that the penetration of SOIL grains into the REINFORCEMENT has a significant impact on the resistance of the REINFORCEMENT to being pulled out of the SOIL. The amount of penetration of solid SOIL grains into REINFORCEMENT increases by reducing the stiffness of the REINFORCEMENT and increasing the size of the diameter of the SOIL grains. For each specific vertical stress level, the greater the penetration of solid SOIL grains into REINFORCEMENT, the higher the pull-out strength of that REINFORCEMENT. The results show that with the increase in the diameter of the solid grains of the SOIL, the pullout resistance of the REINFORCEMENT has also increased, but this increase has been more significant in the case of REINFORCEMENT with lower stiffness compared to REINFORCEMENT with higher stiffness. Also, the difference in the pullout resistance of three REINFORCEMENTs with different stiffness in fine-grained SOIL was less than the difference in the pullout resistance of three REINFORCEMENTs in coarse-grained SOIL, which indicates the simultaneous effect of REINFORCEMENT stiffness and SOIL grain size on pullout resistance.

The degree of SOIL cohesion investigation through the presence of roots is one of the important criteria in SOIL REINFORCEMENT studies. In this study, the investigation and comparison of the degree of SOIL cohesion have been carried out using two models of WWM and FBM. For this purpose, seven hornbeam (Carpinus betulus L. ) trees were selected in each three sites of chalos sarcheshme forest, series one. Then profile trenching method was used to analyze and compare root distribution and standard instron device have been measured tensile strength, respectively. The root area ratio (RAR) has decreased with increasing depth, and the maximum value of RAR in the three sites is seen at about 40 cm from the beginning, and the maximum depth of rooting is 60 cm. The results confirmed that there was a power law relationship between root diameter and tensile strength. The minimum and maximum tensile strength was estimated at 11. 52-323. 42, 6. 89-318. 79 and 6. 91-312. 66 MPa, in diameter range of 0. 59. 45, 0. 56-9. 21, 0. 45-9. 32 in the first, second and third site, respectively. In all three sites, the amount of SOIL cohesion through the presence of roots using the WWM model was 4. 0461. 37, 5. 7-53. 18, 4. 6-46. 66 kpa and in FBM model the root cohesion in all depth was 1. 2227. 48, 1. 87-24. 22, 1. 85-19. 04 kpa in the first, second and third site, respectively. Comparison of these two models increases our knowledge of the biomechanical features of the hornbeam species and more accurately determines the amount of SOIL REINFORCEMENT to be used in the future in the management of natural phenomena such as landslides.