Abstract
The self-balanced pressure arch theory is an important basis for excavation support in karst caves, but it is difficult to quantify the empirical theory in coastal areas. In addition, the rheological effects of karst strata could pose a hazard to engineering. Therefore, this study investigated the rheological mechanism under the self-balanced pressure arch effect, and we proposed a mesoscopic unit rheological model for clay minerals in a water-rich environment. With the discrete element method (DEM), we realized the numerical modeling of the rheological model. Then, the proposed model is validated by a case study of foundation excavation in the coastal karst area of China. The mesoscopic mechanical characteristics of caves considering the influence of pressure arch are analyzed. The results show that the self-balance of the caverns mainly lies in the mesoscopic mineral strength and local stress. With the rheological controlled model, the final predicted convergent deformation of the foundation has an error of less than 10% compared with the field monitoring data. In this study, we can quantitively describe the self-balance effect of the pressure arch surrounding the caves and reveal the rheological mechanism. The proposed model can be applied to similar engineering with careful calibration and provide safety guidance.