基于振动谐波理论的路基压实度在线检测方法与实验研究

On-Line Detection Method and Experimental Research of Roadbed Compactness Based on Vibration Harmonic

针对现有人工检测路基压实度方法不连续,导致路基压实不均匀而引起的路面严重损坏的问题,根据路基压实过程中压路机与土基相互作用产生的振动谐波信号与路基压实度的关联性,研究了传统CCV路基压实度数学模型中各项参数所对应的频率区间,考虑了不同路基类型下压路机钢轮振动谐波信号中高幅值对应频率的分布,提出了基于振动谐波理论的自适应路基类型的CCV修正方法。以振动加速度传感器、NI板卡为硬件采集平台,在虚拟仪器LabVIEW中构建了路基压实度在线检测系统;以土槽实验室的黄土填料路基为实验对象,检测了路基在终压作用下的CCV修正值,并通过环刀法完成了该路段压实度的真实评定。实验结果表明:土基压实过程中,压路机钢轮上采集的振动加速度信号发生了畸变,其频域内信号的主要能量集中在半倍频、基频、1.5倍频、2倍频和4倍频处,且以此谐波分量修正的CCV值的310倍与环刀法压实度值基本对应;根据修正CCV值与环刀法压实度值关系建立的压实度线性模型相关系数为R2 = 0.86,满足现场压实质量评价要求,进一步验证了修正CCV评价方法的正确性。基于谐波法的自适应路基类型的压实度在线检测方法为路基压实施工过程中压实度的实时连续检测提供了理论依据。

Existing methods for manually detecting the degree of roadbed compaction are not continuous, resulting in serious road damage caused by uneven roadbed compaction degree. According to the correlation between the vibration harmonic signal generated by the action of the roller and the soil foundation during the roadbed compaction process and the degree of roadbed compaction degree, the frequency range corresponding to each parameter in the traditional CCV roadbed compaction mathematical model is studied, and the differences are considered, and the distribution of the high amplitude corresponding to the frequency of the vibration harmonic signal of the roller drum under different roadbed types is considered. Therefore, an adaptive subgrade type CCV correction method is proposed based on the vibration harmonic theory. With the vibration acceleration sensor and NI board as the hardware acquisition platform, an online subgrade compaction detection system is constructed in the virtual instrument LabVIEW. Taking the loess-filled roadbed in the soil trough laboratory as the experimental object, the CCV correction value of the roadbed compaction degree under the action of the final pressure was detected, and the roadbed compactness was evaluated by the ring knife method. The result showed that: In the process of soil foundation compaction, the vibration signal of the roller was distorted, and the main energy was concentrated at half frequency, fundamental frequency, 1.5 frequency, 2 frequency and 4 frequency. The 310 times the CCV value corrected by the harmonic component basically corresponds to the ring knife compaction value. The correlation coefficient of the linear model of compaction established based on the corrected CCV value and the ring knife compaction value is R2 = 0.86, which meets the requirements of on-site compaction quality evaluation and further verifies the correctness of the revised CCV evaluation method. The online detection method of subgrade compaction based on the harmonic method provides a theoretical basis for the real-time continuous detection of subgrade compaction during the construction process.