Research Of Dynamic Compaction Vibration Propagation And Applied Technology In Highway Foundation Widening

Due to the rapid development of social economy, limited land resources and increasing traffic pressure, the reconstruction and broaden tasks of highway becoming increasingly onerous. Pavement structure longitudinal cracking, even subgrade instability caused by the differential settlement between existing and widen roadbed is one of key technologies during highway-widening project. While the foundation soil is relatively thick, the differential settlement mainly results from consolidation settlement of newly-widen part. The effort of soil compaction to eliminate the settlement is limited and using of rigid and flexible piles is expansive. Dynamic compaction is an economical and effective method to improve foundation conditions. I lowever, because of the strong vibration of dynamic compaction, the fluctuation effect of dynamic compaction on the base and surface structure is not clear, which made the impact of old subgrade and pavement structural stability under new foundation dynamic compaction vibration is still unclear. The problems described above restrict the use of dynamic compaction technology in the foundation-broaden project.The study uses similar theory to establish large-scale indoor test model and simulate the implementation process of the foundation of the dynamic consolidation road widening.Use FLAC3D numerical calculation software to simulate the model test and dynamic consolidation road widening physical works of the foundation. Upon the laboratory experiments and numerical results, to analyze the influence factors of the vibration of the dynamic compaction point and the law of vibration, research the attenuation rule of the foundation dynamic shock waves in the foundation as well as in the old roadbed pavement structure, mainly about the propagation law of the dynamic shock wave in the subgrade and pavement structure with different hammer weight, diameter, drop distance, embankment heights etc. The study analyzes the dynamic response of the old subgrade and pavement under widening road foundation compaction vibration, including impact on the old subgrade pavement structural strength, stability and personnel safe and driving comfortable. Moreover, the study not only put forward safety criterion and failure criteria about vibration of subgrade and pavement, but also determines the vibration control standards foundation of the roadside dynamic compaction. Based on the mechanism of production and propagation about dynamic compaction vibration, the study proposes new control technology on dynamic compaction vibration damping. The research results have important theoretical and engineering significance on the foundation-broaden engineering of Chinese highway subgrade reinforcement.