Analytical solutions for geosynthetic-reinforced cohesive subgrade spanning trench voids: Fid-Bau Portal

Analytical solutions for geosynthetic-reinforced cohesive subgrade spanning trench voids

Chen, Fu-quan / Lin, Yu-jian / Chen, Shi-xuan

Abstract Geosynthetic-reinforced structures are required for constructing roads in the presence of trench voids. In this study, we propose a novel method with respect to the geosynthetic-reinforced cohesive subgrade spanning trench or column voids. Using this method, we can estimate the geosynthetics deformation $w$ and strain $ε$ by considering various load patterns, the upper interface friction of geosynthetics, the subgrade subsidence, and further investigate the effect of the soil cohesion and the filling in voids on the geosynthetics. Moreover, the node tension bar model was employed with respect to the geosynthetics in the subsided area and the settlement area. The present results were in good agreement with the previous experimental and numerical results. Extensive parametric studies have also been conducted. Thus, the invert parabolic load pattern is the most unfavourable load pattern. Affected by the soil-geosynthetic relative displacement and subgrade soils, $w$ and $ε$ are off by at least 10%. With the loss of fillings in void, $w$ and $ε$ are increased up to 590% and 300%. Reducing the stiffness of geosynthetics leads to increasing $w$ and $ε$ by up to 55% and 250%. In addition, the larger void width results in maximum 260% and 150% increases in $w$ and $ε$ .

Highlights Compared with the previous design methods, this study has the following innovations:• In order to accurately analyse for the deformation and stress state of geosynthetics, a newly tension bars model was proposed. • The proposed method improved the calculation accuracy by considering the soil–geosynthetics interface friction in the subsided area and the soils settlement around the void. • The application scope was further broadened by investigating the effects of the cohesive subgrade, load forms, and fillings in voids. • For fully consideration on the factors of the geosynthetics design, the relative displacement of soil and geosynthetics in the subsided area and the fillings in the void were discussed in the parametric studies for the first time.