Research and application of stress testing apparatus for similar material model test

In view of the shortage of previous stress measurement methods, especially in the following aspects: the compatibility of mechanical characteristics, stability of data acquisition, and model operability between embedded block and the model, a new type of stress testing apparatus has been developed, whose core component is the stress testing brick. The brick is made of the same material as the model, and the production process includes block processing, strain-gauge sticking, moisture-proof insulation processing and sand-coated sealing. Physical tests indicate that the stress testing block is of good moisture-proof insulation properties, and the rate of long-time zero-drift is 3.25%～6.78%, which has little impact on experiment results. And its application in physical modeling experiment shows that the compatibility and deformation coordination of the block and model is excellent, and the moisture-proof insulation properties can adapt to the damp environment during model making and maintenance. Test results can intrinsically illustrate the stress evolution process during excavation, and can offer reference for further research on mechanical mechanism of strata movement and breaking.