Analysis On Dynamic Performance Of Expansive Soil Slope Reinforced With Geogrid Under The Condition Of Seismic Action

In rencent years, earthquake occurs frequently in China, most of which are in western region. Meanwhile, expanseive soils are also distributed in earthquake region. However, there are currently not seismic researches on engineering relating to expansive soil. The construction of expressway expansive soli subgrade has achieved great breakthrough because of flexible supporting of cutting slope which has been successfully applied in many expressways. The technology is related to geogrid reinforced flexible structure, but its seismic capacity is not taken into account initially. Therefore, it is lack of adaptive testing of this technology which will undoubtedly hinder its promotions in the earthquake zone. The flexible supporting structure is consisited of the geogrid flexible supporting expansive soil, drainage and slope protection system, but the dynamic performance of the geogrid flexible supporting expansive soil has not been studied. Therefore, the dynamic performance of expansive soil slope reinforced with geogrid under the condition of seismic action is carried out in this paper.Firstly, analyzed the design theory and reinforcement design principle of the geogrid flexible supporting expansive soli, discussed the methodology of analysis and research on the dynamic performance of expansive soil slope reinforced with geogrid under the condition of seismic action.Secondly, considering hygroscopic soften of expansive soil slope and the geogrid flexible supporting structure, the paper firstly proceeded numerical analysis on the reinforced and unreinforced expansive soil slope basic model, get their dynamic response rules. Comparing their displacement field, shear rate, their shear-strain increment and the time history curve of the monitoring points’s displacement, velocity and acceleration, the dynamic performance of expansive soil slope has been greatly improved after flexible supporting.Subsequently, respectively, for reinforced soil slopes, the pseudo-dynamic calculation model considering the time and phase difference was obtained, to derive the theory formula of the total reinforcement tensile force and critical angel of rupture. Corresponding programs developed, taking the simplify reinforced expansive soil slope as the research object, investigating the effects of soil parameters, seismic acceleration and slope height on the total reinforcement tensile force and critical angel of rupture.Finally, for the defects of the pseudo-dynamic method, based on the geogrid flexible supporting expansive soil slope basic model in FLAC3D, the effects of seismic acceleration, soil parameters, and slope height on the dynamic performance of the geogrid flexible supporting expansive soil slope were investigated. Some rewarding suggestions for the improvement of flexible supporting slope are summarized.