| Dynamic compaction is a method for foundation reinforced, which have the simple craft, the remarkable effect, less construction equipment, low expense, easily controlled quality, extensive application, short construction cycle and so on the merits.Changde-Jishou expressway is of red-sandstone high foundation, because the soil-stone filled foundation is hard to control the compactness and to guarantee the construction quality, which caused the large settlement of the high embankment and the duration to be long and disadvantage for traffic safety. Therefore designs use the dynamic compaction to make up the strong reinforcement to fill the foundation. In order to obtain the construction parameter and the reinforcement effect of the dynamic compaction reinforced red sandstone foundation, large-scale field test that is compaction reinforcing the high earth filled foundation was carried out by optimized compaction design.The large-scale field test has been performed in the experimented road section based on the above question. The soil peripheral deformation, the soil settlement and the different depth settlement have been obtained with different compaction strikes energy through embedding ground the settlement board in the different position. The dynamic compaction theoretical model has been established for analyzing the relations between compaction settlement and compaction degree. Through embedding ground the soil pressure cell in different earth position, recording the dynamic stress-time curve under different compaction strikes with the dynamic strain gauge, the dynamic stress spread and attenuation rule, as well as the dynamic stress change under the continuous compaction strikes had been analyzed. Contours of dynamic stress had been drawn up and the effective range, the depth and length of dynamic compaction caused by P-wave, S-wave and R-wave were analyzed from these contours. Finally the reinforcement effect of compaction on the foundation was carried out on the examination with the plane loading test and density test, the result demonstrated that the effect of reinforcing high embankment by dynamic compaction is obvious.Combine the experiment with other engineering examples, the formula that determines the effective depth of consolidation was deduced with dimensions analysis. The experience formula of reinforcement range was established based on the definition of Bossion ratio. All of these afford reference for design of compaction construction. |
