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.

In design science, in order to avoid the complexity of the problem, many involved factors are removed with simple assumptions. Simplifying design relationships causes uncertainty and reduces the validity of calculations. In this research, it is tried to study and investigate the relationships governing the stability of earthen gables from the perspective of uncertainty. The use of stabilizing piles can increase the stability of the gables as a barrier element against sliding and improve its performance against incoming loads, but the safety factor called the reliability factor alone should not be the basis of decisions because it is calculated by conventional deterministic methods. And it is not able to directly express the effect of uncertainties. Therefore, in order to evaluate and apply the role of uncertainties, it is necessary to use probabilistic concepts and methods. In this research, slope stability has been evaluated by deterministic analysis and limit equilibrium method in GeoStudio software in the Slope/w module. In the second step, with the help of the probabilistic Monte Carlo method, the uncertainties in the problem are analyzed. Modeling of the reinforced gable has been done by Bishab, Janbo and Morgenstern methods. Bishab and Morgenstern's method showed similar and more reliable behavior than Janbo's method. At the end, the results of deterministic analyzes and the probabilistic Monte Carlo method have been compared in different situations. This comparison with Morgenstern's method has been done to investigate the role of four influential factors in the stability of the gable. The results showed that with increasing the distance of the pile from the bed and heel of the gable as well as the angle of the gable, the reliability coefficient and the reliability index decrease exponentially.

The kinematic method of limit analysis approach is applied to study stability of reinforced slopes. The amount and length of reinforcement required to prevent the slope to collapse are determined based on different mechanisms. A new method consisting of horizontal blocks is used in translational mechanism. The failure wedge is divided into a number of horizontal slices involving reinforcements. The reinforcements do not intersect the slices. Thus, they have no direct influence on the inter-slice forces. The presented method can reduce difficulties of stability analysis for reinforced slopes. In this paper, the seismic stability of slopes reinforced with geosynthetics is investigated. The seismic analysis procedure is substituted with pseudo-static horizontal forces. While such an approach ignores the acceleration history of a structure, it is routinely used in practice. It has been assumed that the geosynthetics are uniformly distributed in the height of slope. Based on these assumptions, different possible failure mechanisms are considered and necessary analytical expressions for determining the design parameters are derived for each mechanism. The results of these analyses are presented to illustrate the influence of different parameters such as geometrical parameters of slopes, soil characteristics, and seismic forces on the stability of reinforced earth structures.

Soil slopes are structures that apply in many cases such as roads, rail ways and many others. These structures need to be reinforced in the case of low-resistance ground, loading on a slope or geometric properties such as very steep or high slope. One of the methods for analyzing the behavior and providing appropriate model for designing the slopes is the Schmertmann method. In this method ,the influence of reinforcement in the vicinity of sliding surface is considered so that the vertical component of reinforcement force increase the vertical forces on the slip surface ,thus increasing the shear strength .but pulling out the reinforcement during mass movement and interaction between soil and geotextile and the vertical component of resultant shear stress between them can decrease the resistance forces perpendicular to the slip surface and so the safety factor of the slope. In order to verify the accuracy of the problem, this study is performed using ABAQUS software based on the finite element method .seen as a result that interaction between soil and geotextile has little effect on reducing the resisting force and the factor of safety of slope.

Soil slopes are structures that apply in many cases such as roads, rail ways and many others. these structures need to be reinforced in the case of low-resistance ground, loading on a slope or geometric properties such as very steep or high slope.one of the methods for analyzing the behavior and providing appropriate model for designing the slopes is the Schmertmann method. In this method, the influence of reinforcement in the vicinity of sliding surface is considered so that the vertical component of reinforcement force increase the vertical forces on the slip surface, thus increasing the shear strength. but pulling out the reinforcement during mass movement and interaction between soil and geotextile and the vertical component of resultant shear stress between them can decrease the resistance forces perpendicular to the slip surface and so the safety factor of the slope.in order to verify the accuracy of the problem, this study is performed using ABAQUS software based on the finite element method. seen as a result that interaction between soil and geotextile has little effect on reducing the resisting force and the factor of safety of slope.

This paper describes a FE simulation of the behavior of mechanically stabilized cohesive earth walls under seismic loads and the effects of reinforcements in reduction of deformations under earthquake loads were studied. In this manner, different heights and different systems of reinforcement were considered.First of all, the maximum height of cohesive vertical slope was estimated without any reinforcement. In other words, five different types of cohesive soils were considered and their maximum stable heights were calculated. Then a geotextile reinforcement system was designed for each wall with the recommended method in the research. Also, to be reassured about the better design of the reinforced walls under seismic loads (considering that the used method for design was merely regarded static loads) the walls were modeled and their stress-strain behaviors were obtained under Saint Jose earthquake loading. After some try and error steps, and finding the safety factors in each step, the optimized design was gained. After that, to evaluate the effects of reinforcements in reduction of deformation in retaining systems some comparisons were made between the reinforced and non-reinforced walls with different heights (6m, 8m, 10m, 12m and 14m) The results of stress-strain analysis were tabulated and related curves were presented. The results clearly show that the reinforcement systems force a full control on displacement specially at the top and the middle of the walls which are the critical zones in retaining walls behavior under seismic loads. Finally it was shown using reinforced system in vertical cohesive slopes with common height, under seismic loads, can reduce the X components of deformations more than 90%.