快速液压夯动力补强效果无损评价试验

Test on Nondestructive Evaluation of Dynamic Reinforcing Effect of Rapid Hydraulic Impactor

为了探究快速液压夯动力补强效果,对同种液压夯不同夯实次数处理过的路基开展瞬态面波无损检测,通过钻土取芯并开展土工试验得到了含水率与压实度等相关土体参数随深度变化情况。基于瑞雷波波速及相关土体参数,建立了压实度经验模型,并通过实测数据进行了验证。试验结果表明:瑞雷波波速云图呈现明显的层状分布,干密度和压实度随着路基高程增加逐渐提高,在路基表面处,夯实2组的路基压实度与未夯实路基相比提高了1.95%,夯实4组的路基压实度与未夯实路基相比提高了3.13%;在路基表面处,夯实2组的路基干密度与未夯实路基相比提高了0.91%,夯实4组的路基干密度与未夯实路基相比提高了1.01%。进行瑞雷波速与原位试验实测纵向压实度关系曲线标定时考虑含水率对瑞雷波速的影响进行回归拟合,建立了相关性良好的波速-压实度经验模型,提高了基于瞬态面波的压实度检测方式精度。

In order to explore the dynamic reinforcement effect of rapid hydraulic impactor,the transient surface wave nondestructive testing was carried out on the subgrade treated by the same hydraulic tamper with different tamping times.Through soil coring and geotechnical tests,the changes of soil parameters such as moisture content and compactness with depth were obtained.An empirical model of compactness was established based on Rayleigh wave velocity and related soil parameters,and verified by measured data.The test results show that Rayleigh wave velocity contours show obvious layered distribution,the dry density and compactness increase gradually with the increase of the subgrade elevation.At the subgrade surface,the compactness of subgrade compacted for 20 times is 1.95%higher than that of the uncompacted subgrade,and the compactness of subgrade compacted for 40 times is 3.13%higher than that of the uncompacted subgrade.The dry density of subgrade compacted for 20 times is increased by 0.91%compared with that of the uncompacted subgrade,and the dry density of subgrade compacted for 40 times is increased by 1.01%compared with that of the uncompacted subgrade.The effect of water content on Rayleigh wave velocity was considered for regression fitting during the calibration of the relationship curve between Rayleigh wave velocity and the measured longitudinal compactness in the in-situ test.The empirical model of wave velocity-compactness with good correlation was established,which improved the accuracy of the detection method of compactness based on transient surface wave.