Density measurement of gravel clay material of core wall dam with experiment and numerical simulation based on the additional mass method

Abstract

The compaction density of dam construction material is a key indicator for assessing dam fill quality. Although the additional mass method has been widely used for rockfill density measurement, research on gravel clay material is still limited. Furthermore, the traditional method assumes constant stiffness and vibration mass of rockfill under impact loads, which deviates from the actual situation, and further research is urgently needed. In this paper, a new density measurement method based on additional mass method and numerical simulation is proposed. First, impact force and dynamic response tests were conducted by the additional mass method model test. The effect of the additional mass on the propagation of the impact signal was investigated, and the response characteristics of gravel clay under impact were analyzed. Subsequently, a three-dimensional numerical model is established and the accuracy is verified comparing with the experimental results. The vibration range and dominant frequency of gravel clay are obtained combined with the results of model test and numerical simulation. Based on the variation patterns of vibration mass and dominant frequency, a density-fitting relationship was formulated. The actual vibration mass of the gravel clay was obtained from the fitting results, and the density was subsequently calculated. Finally, the engineering example is used to verify that the calculation error can be controlled within 3%, which proves the feasibility and accuracy of the method. This method fills the application gap of numerical simulation in this field, significantly improves the efficiency and accuracy, and provides a novel strategy for density measurement.