Experimental Research On Embankment Foundation Reinforced By Geogrid Under Dynamic Compaction Loads

The backfilled soil can be compacted by dynamic compaction and the lateral deformation can be limited effectively by reinforced soil, the both methods can strengthen the stability of backfilled soil slope, but they will restrict each other when the two methods used in the same project. It shows that reinforced soil can limit the function of dynamic compaction, on the contrary, the broad dynamic compaction energy can easily lead to fracture failure of reinforced plastic materials. To solve the problem of how to balance and optimize the parameters of dynamic compaction and reinforcement, the paper studies it combined model experimental with FLAC3 D finite difference numerical method.Four kinds of reinforced parameters and the values are adopted by model experimental research, they are embedment ratio of reinforcement material(values 2,3,4,5), reinforcement layers(values 2,3,4,5), reinforcement layer spacing(values 2,4,6,8cm), elastic modulus reduction factors of reinforcement material(values 1,0.75,0.5,0.25). The evaluation indexes of reinforcement effect are effective reinforced depth, crater depth, lateral deformation, lateral earth pressure and subsidence of reinforcement material. The model experimental research are based on the dimensional criteria to establish, and take control variable method to study the degree of single factor’s influence on the test, numerical simulation mainly using the method of orthogonal test and analyzed the various factors on the degree of impact test. The following conclusions are drawn that(1) In order to increase the reinforced soil compaction, it should increase the embedment ratio, reduce the reinforcement layers and reinforced layer spacing.(2) Lateral restraint function mainly reflects in the soil of following locations of reinforcement material, the upper soil reinforcement materials are relatively large vertical compacting effect and lead to the increase displacement on the upper locations of reinforcement material.(3) The ratio of the effective reinforcement depth and the crater depth is exponential grows relationship with the embedment ratio and reinforcement layer spacing, it is linear relationship with reinforcement layers, it is concluded that the single factor calculation formula for estimating the effective reinforced depth.(4) The lateral earth pressure ratio of non-reinforcement and reinforcement is quadratic polynomial relationship with embedment ratio, it is exponential relationship with reinforcement layers.(5) The closer the tamping point near, the greater the strain of reinforcement materials, and the subsidence of reinforcement material is exponential decay relationship with embedment ratio and reinforcement layers, it is exponential grow relationship with reinforcement layer spacing.Finally, it provides the optimal values of reinforcement parameters under the each evaluation index through range analysis method, at the same time, the importance degree for the evaluation indexes are sorted and the comprehensive optimum scheme of reinforcement parameters are obtained. Through multiple linear regression to establish the quantitative relationship between evaluation indexes and the reinforcement parameters, providing the basis for calculation of evaluation indexes. In this paper, the conclusions of reinforced soil foundation strengthened by dynamic compaction have the certain reference value and guiding significance for similar embankment engineering.