This study presents the climatic effects (rainfall and evaporation) on the stability of reinforced soil walls constructed with nonwoven geotextiles reinforcements using numerical modeling. The evaluation of the climatic effects was organized in two steps: (1) numerical modeling of the infiltration compared to a laboratory full-scale model of a nonwoven reinforced soil wall and; (2) a numerical investigation of a hypothetical geosynthetic-reinforced soil wall subjected to climatic changes including precipitation and evaporation, for a period of 2 years. The numerical modeling of infiltration into the full-scale model was conducted using two representative hydraulic parameters of backfill soil (suction and volumetric moisture content). The infiltration modeling of the laboratory reinforced structure was conducted to provide better understanding around the hydraulic behavior and water path into regions not measured by instrumentation during laboratory tests. Numerical calibration was conducted in order to capture the capillary break developed at soil-geotextile interfaces, including the anchorage of the reinforcements in the wrap-around facing. As a second step of this study, a hypothetical reinforced soil wall constructed with nonwoven geotextile was modeled using the same hydraulic properties of soil and geotextile used in the previously described numerical modeling. The climatic changes were simulated considering the water balance at ground surface. The climatic effects on the reinforced soil wall were assessed by the use of soil suction changes and consequent influences on the factors of safety over 2 years of operation. Results from numerical simulation of infiltration into the laboratory model indicated that water breakthrough did not occur uniformly along the length of the geotextile. In addition, numerical infiltration into the laboratory model showed that the water path into the reinforced zone is influenced by the anchorage of the reinforcement in the wrap-around facing. The results of the climatic variations in the hypothetical structure showed that approximately 50% of potential evaporation and total rainfall effectively evaporates and infiltrates. Also, the results revealed that the capillary barrier did not generate significant surface runoff and did not reduce the effective infiltration in the reinforced zone. On the other hand, water was observed to advance faster outside of the reinforced zone than inside of the reinforced zone because of the capillary barrier. Additionally, simulations showed that soil inside of the reinforced zone never recovered its initial suction value after first wetting because the capillary barrier restricted evaporation. Results also revealed that increases in global factor of safety, after first wetting of the geotextile reinforced soil wall, occurred because of the increases in soil suction of the first reinforced layer. Lastly, cumulative precipitation during successive days of rainfall showed some correlation to changes in global factor of safety. / Este estudo apresenta os efeitos das variações climáticas (chuva e evaporação) em muros de solo reforçado com geotêxtil não tecido através de analises numéricas. A avaliação dos efeitos climáticos foi dividida em duas fases: (1) calibração numérica da infiltração em um protótipo de laboratório de muro reforçado com geotêxtil não tecido e; (2) extrapolação dos resultados de infiltração para uma estrutura hipotética incluindo as variações climáticas de chuva e evaporação por um período de 2 anos. A calibração numérica foi realizada por meio de duas variáveis (sucção e umidade volumétrica) medidas durante a infiltração no protótipo. Estudos numéricos do processo de infiltração foram conduzidos para melhor entender o comportamento hidráulico da infiltração em regiões que não foram monitoradas durante a infiltração no protótipo. A calibração numérica foi conduzida com o objetivo de capturar o efeito da barreira capilar na interface solo-geotêxtil não tecido, incluindo a ancoragem do reforço próximo a face envelopada. A partir dos resultados da calibração, um muro hipotético reforçado com geotêxtil não tecido foi modelado sob condições climáticas reais (chuva e evaporação), e seu desempenho foi avaliado através das variações de sucção e do fator de segurança ao longo de 2 anos. As variações climáticas foram modeladas considerando o balanço de hídrico na superfície do solo. Os resultados da calibração numérica do modelo de laboratório indicaram que a barreira capilar na interface solo-reforço rompeu de forma não uniforme ao longo do geotêxtil não tecido. Além disso, a avaliação da infiltração mostrou que o fluxo de água tem sua direção afetada pela ancoragem do reforço próximo a face. Os resultados das variações climáticas na estrutura hipotética mostraram que aproximadamente 50% da evaporação potencial e da chuva total efetivamente evapora e infiltra. Além disso, os resultados revelaram que a formação de barreira capilar, e consequente retardo na infiltração, não gerou escoamento superficial significativo e não reduziu o volume de água efetivamente infiltrado na zona reforçada. Ademais, as variações de sucção observadas na zona reforçada se mostraram diretamente ligadas aos dias consecutivos de chuva. Por outro lado, observou-se que a frente de umedecimento avançou mais rápido fora da zona reforçada do que dentro da zona reforçada devido à barreira capilar. As simulações mostraram que o solo dentro da zona reforçada nunca recuperou seu valor inicial de sucção após o primeiro umedecimento porque a barreira capilar restringiu a evaporação. Os resultados também revelaram que o aumento no fator global de segurança, após o primeiro umedecimento do muro reforçado com geotêxtil, ocorreu devido ao aumento da sucção do solo da primeira camada reforçada. Por fim, a precipitação acumulada durante dias consecutivos de chuva mostrou correlação com as mudanças no fator de segurança.

Use of soil retaining walls for roads, embankments and bridges is increasing with time and reinforced soil retaining walls are found to be very efficient even under critical conditions compared to unreinforced walls. They offer competitive solutions to earth retaining problems associated with less space and more loads posed by tremendous growth in infrastructure, in addition to the advantages in ease and cost of construction compared to conventional retaining wall systems. The study of seismic performance of reinforced soil retaining walls is receiving much attention in the light of lessons learned from past failures of conventional retaining walls. Laboratory model studies on these walls under controlled seismic loading conditions help to understand better how these walls actually behave during earthquakes. The objective of the present study is to investigate the seismic response of geosynthetic reinforced soil wall models through shaking table tests. To achieve this, wrap faced and rigid faced reinforced soil retaining walls of size 750 × 500 mm in plan and 600 mm height are built in rigid and flexible containers and tested under controlled dynamic conditions using a uni-axial shaking table. The effects of frequency and acceleration of the base motion, surcharge pressure on the crest, number of reinforcing layers, container boundary, wall structure and reinforcement layout on the seismic performance of the retaining walls are studied through systematic series of shaking table tests. Results are analyzed to understand the effect of each of the considered parameters on the face displacements, acceleration amplifications and soil pressures on facing at different elevations of the walls. A numerical model is developed to simulate the shaking table tests on wrap faced reinforced soil walls using a computer program FLAC (Fast Lagrangian Analysis of Continua). The experimental data are used to validate the numerical model and parametric studies are carried out on 6 m height full-scale wall using this model. Thus, the study deals with the shaking table tests, dynamic response of reinforced walls and their numerical simulation. The thesis presents detailed description of various features and various parts of the shaking table facility along with the instrumentation and model containers. Methodology adopted for the construction of reinforced soil model walls and testing procedures are briefly described. Scaling and stability issues related to the model wall size and reinforcement strength are also discussed. From the study, it is observed that the displacements are decreasing with the increase in relative density of backfill, increase in surcharge pressure and increase in number of reinforcing layers; In general, accelerations are amplified to the most at the top of the wall; Behaviour of model walls is sensitive to model container boundary. The frequency content is very important parameter affecting the model response. Further, it is noticed that the face displacements are significantly affected by all of the above parameters, while the accelerations are less sensitive to reinforcement parameters. Even very low strength geonet and geotextile are able to reduce the displacements by 75% compared to unreinforced wall. The strain levels in the reinforcing elements are observed to be very low, in the order of ±150 micro strains. A random dynamic event is also used in one of the model tests and the resulted accelerations and displacements are presented. Numerical parametric studies provided important insight into the behaviour of wrap faced walls under various seismic loading conditions and variation in physical parameters.