Prediction of brittle rock failure severity: An approach based on rock mass failure progress

This study presents the classification and prediction of severity for brittle rock failure, focusing on failure behaviors and excessive determination based on damage depth. The research utilizes extensive field survey data from the Shuangjiangkou Hydropower Station and previous research findings. Based on field surveys and previous studies, four types of brittle rock failure with different failure mechanisms are classified, and then a prediction method is proposed. This method incorporates two variables, i.e. Kv (modified rock mass integrity coefficient) and GSI (geological strength index). The prediction method is applied to the first layer excavation of the powerhouse cavern of Shuangjiangkou Hydropower Station. The results show that the predicted brittle rock failure area agrees with the actual failure area, demonstrating the method's applicability. Next, it extends to investigate brittle rock failure in two locations. The first is the k0+890 m section of the traffic cavern, and the second one is at K0-64 m of the main powerhouse. The criterion-based prediction indicates a severity brittle rock failure in the K0+890 m section, and a moderate brittle rock failure in the K0-64 m section, which agrees with the actual occurrence of brittle rock failure in the field. The understanding and application of the prediction method using Kv and GSI are vital for implementing a comprehensive brittle rock failure prediction process in geological engineering. To validate the adaptability of this criterion across diverse tunnel projects, a rigorous verification process using statistical findings was conducted. The assessment outcomes demonstrated high accuracy for various tunnel projects, allowing establishment of the correlations that enable valuable conclusions regarding brittle rock failure occurrence. Further validation and refinement through field and laboratory testing, as well as simulations, can broaden the contribution of this method to safer and more resilient underground construction.