基于压路机—土体非线性系统动力响应的压实质量连续检测方法研究

Continuous detection method based on the dynamic response of roller-soil system is the development direction of compaction quality detection. The calculation model of dynamic response of roller-soil system, identification method of dynamic parameters of soil mass and quantitative relation between dynamic parameters and compaction index are three main factors that influence detection result. Through the field test and analysis of the dynamic response parameters of the roller, this study revealed the influence of the degree of compaction of soil on the vibration mode of roller, and also revealed the contact relation between wheel and soil. A dynamic tri-axial test was employed to obtain the soil deformation characteristics under the load of vibratory roller, and to determine a calculation model suitable for the roller-soil system. The dynamic response signal of the system was analyzed based on the established dynamic response calculation model of roller-soil nonlinear system that reflects various vibration modes and roller-soil contact relationship. The method and index for identifying the vibration mode of roller were also given. The incremental harmonic balance method was used for the identification of the dynamic parameters of soil mass under different vibration modes. Based on the comparative test and theoretical analysis, the relationship between soil dynamic parameters and compaction index was established. Thus, an index was proposed for the detection of continuous compaction quality. This research result will improve the basic understanding for the detection of continuous compaction quality. It will also provide theoretical support in realizing higher precision of compaction quality detection and in assuring the compaction quality of earthen structure.

基于机-土系统动力响应的连续检测方法是压实质量检测的发展方向。机-土动力响应计算模型、土体动力参数识别方法、动力参数与压实指标的量化关系是影响检测结果的三个主要因素。本项目通过对压路机动态响应的现场测试分析，给出压路机振动模式与轮-土关系的判别方法与指标；通过动三轴试验，获得振动压路机荷载下土体变形特征，确定适用于机-土系统的土体计算模型；建立反映多种振动模式、轮-土接触关系、土体变形特征的机-土非线性系统动力响应计算模型；分析系统动态响应信号，利用增量谐波法识别机-土系统多种振动模式下的土体动力参数；从作用于土体能量与土体位移关系出发，阐明土体动力参数与压实指标的内在关系，提出压实质量连续检测的指标。研究成果将完善压实质量连续检测的基础理论，为提高压实质量检测结果的准确度，保证土工构筑物压实质量提供理论支持。

压实质量检测是确定压实状态最主要的方法，机-土耦合作用计算模型、土体动力参数识别方法、动力参数与压实指标的量化关系是影响压实质量检测精度的三个主要因素。本项目通过数值模拟和室内外试验，建立了能反应多种状态的轮-土耦合作用的计算模型，分析了不同压实状态下振动轮的动态响应特征；利用增量谐波法识别土体动力参数，提出了有明确力学意义的压实质量连续检测新指标。根据不同填料现场测试结果，验证了不同类型填料连续压实检测指标的适用性，获得了常规压实质量检测指标与新指标的相关性，确定了连续压实质量指标随压实度的变化规律；考虑了轮-土系统非线性、土体压实程度变化对振动轮动态特征的影响，根据轮-土接触关系，提出了跳振判断指标，能有效消除压路机跳振所产生的检测异常值；根据压实连续检测数据特征，提出了基于自相关距离的近邻加权估计法用于识别连续压实数据异常点；基于地统计理论的空间数据分析方法，提出采用半变异函数对压实程度的均匀性进行判断。研究成果为提高压实质量检测和评价提供了理论基础。