高能级强夯法在吹填土地基处理中的应用分析与探讨

Application Analysis and Discussion of High Energy Level Dynamic Compaction in Reclaimed Ground Treatment

东南沿海地区吹砂填海地基地下水位较高,素填土层较厚,且夹杂淤泥质黏土,导致地基承载力不足,后期沉降较大,地基处理难度大。为了探讨高能级强夯法对这类吹砂填海地基的加固效果,基于高能级强夯法在某绿色石化基地二期工程低温罐区吹填土地基处理中的实际应用,对高能级强夯法处理吹填土地基的可行性进行了分析。强夯结束后分别运用静载荷试验、瑞利波法、重型动力触探试验进行现场检测。结果表明:夯后瑞利波波速明显提升,土性明显改善;通过静载荷试验P-s曲线及夯后瑞利波波速值与承载力特征值的关系式,得到夯后素填土层地基承载力特征值≥250 kPa,使上部素填土层形成了硬壳层并同时提高了土层的压缩模量;通过夯后重型动力触探N63.5修正值(击)及夯后瑞利波波速值与承载力特征值的关系式,得到夯后吹填土层地基承载力特征值≥130 kPa。这表明高能级强夯法在处理素填土层较厚的吹填土地基时,不仅对素填土层有明显的加固效果,而且对吹填土层的承载力、压缩模量也有明显的提升效果,地基各项力学性能指标均能满足设计要求,同时对地基稳定性的改善也起到了关键性作用。

In the southeast coastal areas of China,the groundwater level of sand blowing reclamation foundation is higher and the plain filling layer is thicker with mixed silt clay,which results in the insufficient bearing capacity of the foundation,the larger settlement in the later stage.It is difficult to treat the foundation.In order to explore the reinforcement effect of high energy level dynamic compaction method on the kind of blowing sand reclamation foun-dation,the feasibility of the method in the treatment of the second phase is analyzed in a green petrochemical base based on the application of the method.After the dynamic compaction,the static load test,Rayleigh wave method and heavy dynamic sounding test are conducted on-site detection.The results show that both the wave speed of Rayleigh wave increased and the soil property improved greatly;Through the P-s curves of static load test and the relation-ship between the Rayleigh wave velocity and the characteristic value of bearing value,it is obtained that the charac-teristic value of the plain filling layer foundation after compaction≥250 kPa,which forms a hard shell layer in the upper plain flling layer and increases the compressive modulus of the soil layer;Through the correction value of heavy dynamic sounding N63.5(strike)and the relationship between the Rayleigh wave velocity and the character-istic value of bearing value,it is obtained that the characteristic value of the hydraulic filling layer foundation after compaction≥130 kPa.This shows that high energy level dynamic compaction method in the treatment of the flling layer thicker filling base,not only has obvious reinforcement effect on the filling layer but also on the bearing capac-ity in flling layer,compression modulus.All the foundation mechanical properties indexes can meet the design re-quirements.At the same time,the method plays an important role in the improvement of foundation stability.