| GRPS(geosynthetics reinforced pile supported)embankment is a new type of foundationtreatment. Practice shows that, using GRPS structure, we will get some benefits such assaving time, reinforcing the embankment with a larger depth soft soil, improving theconstruction quality, having a small effects of adjacent building, having a small lateraldeformation and post-construction settlement. Especially, this kind of embankment is suitablefor the important engineering. It is a effective solutions for building the embankment on thesoft soil. And it has been widely applied around the world. However, it has a complicatedinteraction between the fill soil, geosynthetics, pile and soft soil. And there is no designstandard for this kind of structure in our country. People relies mainly on the designexperience. And the studies of the GRPS around the world are more likely based on stadiccondition. Therefore, it is important to study the behavior of the GRPS embankment under thetraffic load.In order to get some significant point, experimental and numerical studies wereconducted in this paper. Firstly, Special attention was paid to the influence of several keyfactors on the performance of the geogrid. The investigated key factors include stress level,different material and loading time. Secondly, based on the indoor test, put forward theconstitutive model of the geogrid who can reflect the variation of the modulus and thecumulative plastic deformation. Then program composition that we can use the model infinite element software. After that analogue simulation was conducted, and the results of thesimulation can be compared to the experimental study to validate the simulation. Then, baseon the validated constitutive model, another simulation of the GRPS embankment wasconducted to get the change rule of the deformation of the GRPS embankment and theloading relationship between pile and soil under the traffic load. The same that, the results ofthe simulation should be validated by comparing to the field case. Lastly, special attentionwas paid to the influence of several key factors on the performance of the embankmentsindicated by settlement of the embankment and lateral deformation of the embankment. Thekey factors include modulus of the geogrid, modulus of the soft soil, modulus of the pile, pilespacing. According to the behavior of the GRPS embankment under traffic load. we could improve the design of this kind of embankment.The studies showed that:(1)Geogrid reinforced embankment and pile supportedembankment could both reduce the deformation of the embankment according to the studiesof four kind of different condition embankment such as: unreinforced and no pile supported,reinforced and no pile supported, unreinforced and pile supported, reinforced and pilesupported. And pile supported embankment plays a more important role in reducing thedeformation of the embankment.(2)According to the studies above, geogrid reinforced couldreduce the settlement and the lateral deformation, however, we could only get little benefit byenlarging the modulus of the geogrid when up to2000Mpa.(3)Piles bear most of the upperloads, and transfer it to the supporting layer. However, like the geogrid, we could get smallbenefit by enlarging the modulus of the pile when it up to2500Mpa.(4) Pile spacing has aclose relationship with the stress sharing between the pile and soil. Hence, it also impact theload of pile. By decreasing the pile spacing we can reduce the deformation of theembankment.(5)According to the studies of the four key factors, we could evaluate the effectsize of the four factors, and divide it into three level: low, middle, high. The result is thatmodulus of geogrid has a low effect, modulus of soft soil has a middle effect, modulus of pileand pile spacing have a high effect. |
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