The Study On The Barrier Method Of Dynamic Stress Propagation In The Formation Of Dynamic Compaction

The dynamic compaction method to deal with the foundation is simple and suitable for a wide range of soil quality, its effect is remarkable, and the cost is low. But the vibration wave generated by the dynamic compaction can cause significant damage on the surrounding building structures, therefore it is necessary to study the vibration propagation law and the attenuation law caused by dynamic compaction, to study the influence degree and the vibration effect of the building structures around them, further we develop the corresponding isolation measures.According to the domestic and foreign research status and the vibration wave of the composition and the theory of wave, the vibration isolation mechanism of vibration isolating piles is analyzed. This paper presents a new type of hollow steel pile as the vibration isolation to achieve the purpose of reducing vibration hazard.Firstly under impact load, through the indoor model test, the vibration wave propagation and attenuation law in the sandy soil is studied, and probes into the vibration isolation effect of the hollow steel pile, the ideal results are obtained.Secondly, in order to eliminate the boundary effect, increasing the vibration wave propagation path, we had the outdoor field test, better study the spread characteristic of the wave and the vibration isolation effect of vibration isolation pile, provide effective basis for construction design.Finally the finite element model is established, field test results is verified by numerical simulation, and analyzed several factors influencing vibration isolation effect of vibration isolation pile: pile length, thickness and width of cross section. Results show that the vibration isolation pile length on the influence of the vibration isolation effect is obvious, the longer the pile length, the faster the acceleration peak value of the post test points, vibration isolation effect is better, but when it reaches a certain threshold, adding length has little effect on the vibration isolation performance; The vibration isolation pile wall thickness on the vibration isolation effect is not obvious, the pile wall thickness decreases, and the peak value of the measured point acceleration can also be attenuated, but the attenuation degree is not significant; The vibration isolation pile cross section width on the vibration isolation effect is not obvious. When using the dynamic consolidation method to deal with the foundation, the conclusion for setting the vibration isolation pile to protect the existing building has a guiding significance.