强夯参数对夯击效果影响的室内模型试验研究

Model test study on the effects of impact parameters on tamping effect

摘要:

为了研究强夯法的加固机理和强夯过程中土体的变形规律，专门设计了半模型试验箱和用于测试动应力的微型土压力盒，采用半圆模型夯锤，进行强夯法加固粉土地基室内模型试验。分析了夯击次数、落距、能级和锤径等参数变化时，土体内部动应力和位移的变化规律，研究了各种参数变化对强夯加固效果的影响。试验结果表明：在能级一定时，单击夯沉量和影响深度随着夯击次数的增加而逐渐减小，累积夯沉量和影响深度随着夯击次数的增加而逐渐增加；在不同能级作用下，随着落距的增大，影响深度总体是在不断地减小；夯坑深度和影响深度都随着能级的增加而逐渐增大，影响深度与夯坑深度比值介于3-4之间；影响深度随着锤径的增大而减小，影响宽度则随着锤径的减小而有所增大，这是由于随着锤径的增加，锤底面积在不断增大，单位面积上的夯击应力却在不断减小，导致影响深度减小。

Abstract:

In order to study reinforcement mechanism and soil deformation law during dynamic compaction, the half model test box, the miniature earth pressure meter and the semicircle model hammer were specially designed, and the indoor model test was carried out. According to the test results, the variation of the dynamic stress and displacement in the soil were analyzed, and the effects of various dynamic compaction parameters on reinforcement effect of were evaluated. It can be seen that the single crater depth and the single influence depth under a specific impact energy level are gradually decreasing with the increase of the drop number; however, the total crater depth and the influence depth are gradually increasing. The influence depth is decreasing with the increase of drop height. The crater depth and the influence depth are gradually increasing with the increase of impact energy, and the ratio of them is between 3 and 4. With the increase of the hammer diameter, the influence depth is gradually decreasing, but the influence width is increasing, which is mainly attributed to that the impact stress on the unit area is decreasing.