Mechanistic Estimation of Lightweight Deflectometer Target Field Modulus for Construction Quality Control

摘要

The lightweight deflectometer (LWD) is an emerging device for evaluating the quality of compacted layers. Establishing the proper field target modulus for the LWD is crucial for judging the quality of the compacted unbound layers. A rigorous numerical approach to determine the project-specific field target values for a LWD device during the pavement design process is presented in this study. The input parameters to the model include the thickness of the layers, as well as the nonlinear stiffness parameters of each layer estimated from the resilient modulus tests. Simple relationships are proposed to estimate the target modulus when the earthwork can be approximated as a single layer. A parametric study was performed to quantify the impact of the input parameters on the estimated target modulus. The applied load and the plate diameter of the LWD along with some of the nonlinear soil parameters significantly affect the target modulus. The processes of the development and validation of these models are presented in this paper. Furthermore, the impact of moisture variation on estimated target LWD modulus is discussed.