Research on influencing factors of non-stress gauge measurement on mesoscopic scale

Abstract

Abstract Concrete stress is an important item of dam safety monitoring. The stress of dam body can be mastered and the safety degree of dam can be estimated through systematic monitoring and analysis of the stress and strain of concrete. Non-stress gauge, as well as a strain gauge group, is used to monitor the stress and strain of concrete dams. The stress-free strain of concrete can be obtained by utilizing a non-stress gauge, which is the basis for stress analysis. Results of stress-free monitoring are influenced by surrounding environments, instrument structure, and installation method. Finite element numerical simulation and meso-mechanical methods are used to study factors, such as non-uniform temperature field around the gauge, stiffness of a bucket, and aggregate state of concrete. Results show that the stiffness of bucket and non-uniform temperature field slightly influence the results of non-stress strain measurements. In addition, when the aggregate content is the same, the influence of the aggregate distribution is less. However, extra-large aggregate removal method significantly influences the monitoring results. The influence of the removal method on the stress analysis to monitor the data of the strain gauge group is evaluated using an example. Recommendations to deal with extra-large aggregate in the installation of non-stress gauges are presented.