土体含水率监测的移动点热源法研究

Vibration characteristics of super large centrifuge foundation

土体含水率监测的线热源法对加热功率要求较高,当热源强度不稳定时,监测结果容易受到影响。为了解决线热源法的不足,提出了土体含水率监测的移动点热源(point heat source,PHS)法。该方法利用土体热物性与含水率之间的相关性,通过监测土体中PHS的降温规律间接识别含水率。通过数值模拟研究了点热源在含水率均匀分布的土体中的传热规律,根据热源降温曲线的特征,定义了含水率判别指标η,进而建立了含水率与判别指标的拟合关系,并对监测灵敏度的影响因素进行了参数分析。在含水率非均匀分布的土体中开展了点热源降温规律的数值模拟,根据测点降温时程曲线计算含水率判别指标,并利用含水率与判别指标的拟合公式反演含水率分布。结果表明,点热源法反演得到的含水率分布与实际值吻合较好,验证了该方法的理论可行性。通过模型试验进一步验证了该方法的可行性。

A super large centrifuge foundation was buried in the soft soil. The study of its natural vibration characteristics was very necessary and important. The equivalent soil spring model and structure-soil coupling model were established to compare and analyze the vibration characteristics based on different foundation simulation methods. The dynamic time history analysis was carried out based on the white noise excitation to analyze the influence of the foundation participating mass on the vibration characteristics. The first two modes of the super-large centrifuge foundation are horizontal and vertical swings. The vibration modes obtained by different foundation simulation methods are consistent, and the natural frequency difference is within 3%. The foundation participating mass of the first two modes are 1.376 times and 0.998 times the total foundation mass respectively. The vibration response amplitude of the structure will be reduced by about 50% and the peak frequency of the spectrum will be reduced by about 2 Hz if considering the influence of the foundation participating mass. The conclusions have guiding and reference significance for the vibration research of the embedded large scale power machine foundation.