强夯加固粉煤灰及下伏的淤泥质软土地基试验研究

以南京扬子石化储油罐地基处理工程为背景,对粉煤灰及下伏的淤泥质软土地基进行了强夯试验研究。试验中首先对夯坑周围地表沉降以及孔隙水压力进行了检测,然后通过室内土工、载荷、标准贯入、静力触探等试验对强夯加固效果进行了检验。试验表明:强夯采用初始低能量夯击,逐步增加夯击能量和夯击遍数的施工工艺,辅以设置碎石垫层和竖向塑料排水板以及夯点采用梅花形布置的方法,效果明显,使地基的物理力学性能和抗变形性能显著提高,消除了上部粉煤灰层的液化问题,整体加固效果很好,夯后各项指标完全达到或超过预期值;同时通过对试验数据的分析研究,获得强夯法加固该类地基土的最佳强夯参数和施工工艺。

Experimental study on improvement of fly ash underlying silty soft soil by dynamic compaction

Taking a large oil tank foundation project of Yangzi petrochemical company for example,we conduct an experimental study on dynamic consolidation of the filled fly ash underlying silty soft soil.At first,the surface settlement around craters and pore water pressure are inspected,and then the improving effects are detected through laboratory soil mechanics test,load plate test,standard penetration test,cone penetration test,etc.The test shows that it is obvious to improve the foundation with construction technology of low energy in the beginning and gradually growing energy and cycles combined with gravel cushion,vertical plastic drainage board and the layout of cinquefoil for tamping point.The mechanical property and anti-deformation characteristics are improved obviously and the liquefaction problem of the upper fly ash is eliminated.The whole consolidation effect is remarkable, and physical-mechanical properties are better than the expected.At the same time,the optimal parameters and construction techniques are obtained by analyzing the measuring data.