1. Introduction: The present paper, illustrated the results of numerical investigation and a series of experimental modeling on optimization of pile length in reinforcing earth slopes using piles. In this paper, the length of different piles with various diameters analyzed and the relationship for optimal length proposed. Stabilization of earth slopes and proposing different methods is one of the main issues in geotechnical engineering. Using numerical and analytical methods in stabilization of earth slopes reinforced by piles are common method, which, carried out by lots of researchers. Finding the optimal length of piles in reinforced slopes is an important matter that reduces the expenses and make the project economical...

Earth slopes stabilization is one of the main issues in geotechnical engineering. The use of stone columns is one of the approaches for properly increasing the safety factor of earth slopes of the soil embankments. Furthermore, it is economically efficient and is easy in implementation. The present paper aims at an experimental comparison of the Ordinary Stone Column (OSC) and Rigid Stone Column (RSC) behaviors in sandy slopes. These tasks were carried out by constructing an embankment sandy slope, and then, saturating it with rain and, finally, loading increment. The experimental results of laboratory modeling have been also verified through the three-dimensional finite difference method. Laboratory modeling and numerical analyses results showed that the existence of rigid stone column in the middle of the slope (as the optimal placement location) enhances the sandy slope stability up to 1. 36 times compared with a slope reinforced by ordinary stone columns.

The stability of soil slopes and the determination of safety factors have always been the subject of study for engineers and researchers. The safety factor of slopes can be determined by using the methods of limit equilibrium method (L.E.M.), limit analysis, and strength reduction method (S.R.M.). The equilibrium method determines the slope safety factor based on the equilibrium of the inter-slice force and without the analysis of tension and strain. In the strength reduction method, based on the tension-strain analysis, the strength of various points of the slope is reduced until it reaches the critical state, and by connecting all of the critical points, the critical rupture level will be obtained. Finite element software and finite difference software determine the safety factors in soil slopes by using the concepts of the strength reduction method. In this paper, the safety factors of soil slopes are determined by using ABAQUS software, and using the concept of strength reduction method. There is no option in ABAQUS for the determination of safety factors and it should be obtained by defining the concepts of strength reduction. The purpose of this study is to implement a strength reduction method in a finite element program to calculate the safety factor of slopes. The results of this research indicate that the changes in friction angle affect the safety factor changes more than variations in cohesion. Also, slope angle and its changes affect the safety factor changes more than other factors.

1. Introduction: Stabilization of earth is one of the main issues in the geotechnical engineering. A common method for reinforcing earth slopes is using stone columns. In all earth slopes, the primary way for stabilization is the excavation in slope crest and/or filling slope toes, if this action would not increase safety factor enough, other procedures should applied. Three common styles of stabilization methods are; vertical reinforcement (such as stone columns), horizontal reinforcement (like geotextile layers), oblique reinforcement (such as nailing). Using numerical and analytical approaches in reinforced slope stability by stone column is the common method which done by many researchers. Earth slope stability threaten by various factors such as earthquake forces, water table changes, filling upstream and cutting downstream of slope, which increase active forces and finally cause slope instability. When we are suspicious about stability of earth slopes, immediate actions and preventative steps should use for suppression of instability occurrence. The purpose of this research is experimentally and numerically investigates stone column behavior and penetration depth in stiff layer in twolayered sandy slope. In this article sandy slope constructed and the model saturated by raining technique and then loading process carried out. With regard to the processes mentioned above, the penetration depth in stiffer layer gained which is the innovation of this paper. The acquired results confirmed by three-dimensional finite difference method (FLAC 3D). The results of experimental modeling and numerical analysis also indicate that presence of stone column in middle of two-layered sandy slope has a great impact on stability of reinforced slope. . .

The stability of earth dams is assessed through safety factors, indicating stability if they exceed one. Due to soil property uncertainties, fuzzy logic tools seem suitable for slope stability analysis. Uncertainties in parameters like unit weight, cohesion, and internal friction angle can be encompassed by fuzzy set theory. This study employs fuzzy set theory to analyze slope stability factor of safety, considering the varied materials and soils in earth dams. Information and parameters were gathered, and slopes were modeled using Slide (v. 6) software. Shear strength parameters and safety factors were categorized based on results and expert opinions, defining ranges for each. MATLAB software applied fuzzy logic rules to relate inputs (unit weight, cohesion, friction angle) to the output, factor of safety. Comparing results from probabilistic and fuzzy methods revealed close numerical alignment. The fuzzy method, with adaptable rules accommodating different conditions, yielded quicker and more accurate safety assessments, assuming specific data inputs. Overall, the fuzzy approach offers flexibility, facilitating quicker and more accurate determinations of safety factors, albeit requiring specific data assumptions.