Comparación entre diferentes métodos de diseño, para muros con suelo reforzado con geosintético

Abstract

For several decades, reinforced soil has been used as an alternative in construction processes in the field of Civil Engineering and according to these processes, various design methods have been developed, which include input data, calculation processes and particular results. for each of them. In the current bibliography there are several design methods for walls with geosynthetic reinforced soil, however, the results that these methods generally have significant differences, and it is not explained why each method differs from the other. In this titling work, a comparison of three main design methods is made: the first method proposed by the Federal Highway Administration (FHWA) in its publication number FHWA-HRT-11-026, the second one proposed by National Cooperative Highway Research Program (NCHRP) in its report 556, and a third method called FHWA Simplified Procedure developed from the AASHTO LRFD Bridge Design Specifications. The three methods are applied to four specific cases of local soil types. The characteristics have been obtained from field investigations by the PRECUPA project; all this based on the comparison of the input data, in selected ranges of values, processes that execute each of the methods and the results they produce. Geogrids and geotextiles have been used in the design as they are the recommended types for soil reinforcement. The most versatile method in the face of variations in the values of the proposed parameters, complying with the limits and specifications is the third method, FHWA Simplified procedure, considered the most used for the design of mechanically stabilized earth walls, MSEW, it has factors of load and resistance, safety factors for the design of the reinforcement, for which it is considered as a balance-limit design; with stability compliance percentages greater than 75% and percentages of influence of parameter value variations less than 51%. The most influential parameters on the three methods in general are: the friction angle of the reinforced soil, vertical spacing of the geosynthetic reinforcement, dead load due to the bridge, height of the upper wall, and the type of soil retained-foundation, the latter being the one with the highest percentage of variation with respect to the values of the base design. Both the spacing of the reinforcement and the height of the reinforced wall have a great influence only on Method 2, FHWA GRS - IBS Method, due to the amount of data that the equations handle for the calculation of failure modes.