# Geosynthetic Reinforced Steep Slopes: Current Technology in the United States
## 7 Conclusions & Recommendations  
The purpose of the study was to provide a review of the current technology on geosynthetic reinforced steep slopes in the United States. The following conclusions were made based on a comprehensive review of technical reports, journal articles, transportation agency specifications, and case studies, as well as surveys and interviews of academic and industry professionals:  
1. Reinforced slopes are a form of mechanically stabilized earth that incorporate planar reinforcing elements for the construction of sloped structures with inclinations less than 70\({}^{\circ}\). To provide tensile resistance and stability, geosynthetic reinforcement has been employed for repairing failed slopes, constructing new embankments, and widening existing embankments. 2. According to the survey, following the FHWA design guidelines is the most advocated approach for designing reinforced slopes. Other common design methods have been developed by [PERSON], Leshchinsky, and Eurocode. Internal and external stability are considered, including rotational, sliding, bearing, and lateral failure. 3. Geogrids and geotextiles manufactured from polyester, polypropylene, or polyethylene are commonly used for reinforcement. The material must be resistant to all naturally occurring alkaline and acidic soil conditions, resistant to heat, ultraviolet light, and to attack by bacteria and fungi in the soil. 4. An adequate subsurface investigation should be performed for the existing foundation, as well as behind and in front of the structure, to assess overall performance behavior. To facilitate compaction, a high quality fill meeting gradation, shear strength, and internal friction angle requirements are recommended for the embankment soil. 5. The reinforcement is placed with the principal strength direction perpendicular to the face of the slope, pulled taut, and secured with retaining pins to prevent movement during fill placement. Backfill material is placed and compacted without deforming the reinforcement, utilizing lightweight compaction equipment near the slope face to maintain alignment. Performance monitoring programs are recommended for cases in which new features or materials have been incorporated in the design, post construction settlements are anticipated, or where degradation/corrosion rates of reinforcements are to be monitored. * Geosynthetics can be degraded by a combination of environmental mechanisms. However, none of the documented failures were due to inadequate reinforcement. All failures within the reviewed body of literature were due to improper design in the area of surface and internal water removal or the use of fine grained silt and clay backfill soils. * Many site specific characteristics contribute to the overall cost, including cut-fill requirements, slope size and type, existing soil type, available backfill materials, facing finish, and application. The approximate costs of the principal components are as follows: reinforcement 45-65 percent, backfill 30-45 percent, and face treatment 5-10 percent. The following recommendations were made based on the knowledge and experience gained during the study:  
1. There is a need to use the specification and construction checklists, as well as implementing a comprehensive performance monitoring program, in order to compare the observed behavior and the intended design. 2. The FHWA design guidelines should be followed. In addition, there is a need to follow the existing topography, soil properties, and subsurface conditions in evaluating the construction site. The investigation should also seek to determine the backfill materials as well as availability of the required type of reinforced fill. 3. It is also recommended that the polyester, polypropylene, or polyethylene's constructed geotextile or geogrid should be used in reinforcing deep slopes. The materials should have characteristics such as heat resistance, ultraviolet resistance, and fungi and bacteria attack resistance, as well as resistance to alkaline and acidic soil conditions. 4.