This study presents a stability analysis of a high‐steep rock slope with two faults during excavations and evaluates the effectiveness of a proposed reinforcement method using prestressed anchor cables. A 3D finite difference model was established based on the strength reduction method using FLAC3D software. The influence of various fault conditions and the effectiveness of the reinforcement on the slope stability during the excavation process were analyzed and compared to field monitoring data. The numerical analysis and field monitoring results showed that the fault close to the slope surface (f20) was prone to the local instability under external forces caused by the excavation, but a fault further away from the slope surface (f14) had insignificant influence on the stability of the slope. Based on the numerical analysis results, the proposed reinforcement measure can increase the factor of safety (FOS) of the slope by 19.2%. The field monitoring data also showed that the displacement of the monitoring point gradually decreased after the reinforcement, and the deformation of the slope was effectively controlled.

This paper mainly investigates the fracture parameters of Basalt Fiber Reinforced Concrete (BFRC) with various fiber lengths and dosages using Double‐K fracture model. The model was developed by fracture criterion using ABAQUS Virtual Crack Closure Technique (VCCT), and the results of the model and experiments were compared. The basalt fiber with length of 6 mm and 12 mm was added into concrete in the dosage of 0.0%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% by volume of concrete, respectively. Concrete specimens were cast into three dimensions, i.e., 60 mm × 180 mm × 480 mm, 80 mm × 240 mm × 640 mm, and 100 mm × 300 mm × 800 mm. Then, three‐point bending test was conducted on precast‐notched beams. The load versus cracking mouth opening displacement (P‐CMOD curve) was developed in order to evaluate cracking and breaking load. The initial fracture toughness and unstable fracture toughness were derived from the Double‐K fracture model aimed to optimize the fiber length and dosage. The results showed that the initial fracture toughness and unstable fracture toughness increased first and then decreased with the increase in fiber dosage, and basalt fiber with length of 6 mm and dosage of 0.2% performed the best toughening effect on concrete. The comparison results showed that numerical simulation can better simulate the initiation and propagation of BFRC fractures and achieve the dynamic propagation process of fractures.

High concrete‐face rockfill dams (CFRDs) with heights of over 100 m have been quickly developed in recent years. The self‐weight of rockfill materials causes creep deformation of the dam body. However, the creep analysis method of high CFRDs in finite element software is few, and sometimes, it can also not reflect the long‐term performance of high CFRDs well. Therefore, it is necessary to carry out the secondary development in finite element software. This study developed a subroutine that can run in Finite Element Method (FEM) platform ABAQUS to simulate long‐term creep deformation behavior of the rockfill materials more accurately. Then, a displacement back‐analysis for parameters, based on the Xujixia high CFRD project, is performed by the neural network response surface method (BP‐MPGA/MPGA). Remarkable agreements are observed between simulation and field monitoring results. The calibrated FEM model is used to predict stress and deformation behavior of the Xujixia high CFRD after three years of operation period. The result indicates that rockfill creep deformation has a significant impact on stress and deformation of the high CFRD during the operation. This research may predict long‐term performance using FEM in the design stage for high CFRDs.

To investigate the failure effects of critical fissures in rock specimens subjected to plane strain compression (PSC), five types of internal fissures in rock specimens were designed and twelve PSC tests were conducted for two lithologies based on the discrete element method (DEM). The results were analyzed in terms of the fracture mode, data characteristics, and crack evolution. The results indicated the following. (1) The rock samples with a critical fissure under PSC showed a weak face shear fracture mode, which was influenced by lithology, fissure angle, and fissure surface direction. (2) There were four critical expansion points (CEPs) of axial stress of the rocks under PSC, which were the stage signs of rock materials from local damage to complete fracture. The rock-bearing capacity index (RockBCI) was further proposed. (3) The bearing capacity of rock samples with horizontal fissures, fissures whose angles coincided with the fracture surface, and fissures whose surface was perpendicular to the lateral confine direction was the worst; their BCI² values were found to be 80.6%, 70.8%, and 56.9% of the rock samples without any fissures, respectively. The delayed fracture situation under PSC was identified and analyzed. (4) The crack evolution followed the unified law of localization, and the fissures in the rocks changed the mode of crack development and the path of the deepening and connecting of crack clusters, as well as affecting the time process from damage to collapse. This research innovatively investigated the behavior characteristics of rock samples with a fissure under PSC, and it qualitatively and quantitatively analyzed the bearing capacity of rock mass from local damage to fracture.

Energy sustainability and the establishment of the ‘national water network’ are all inseparable from the construction of underground engineering. Monitoring indices for the surrounding rock are vital for the safety management of underground engineering construction, which determines the actual state of the surrounding rock. The complexity of deep underground engineering construction leads to many situations that cannot be predicted and explained by existing experience. Therefore, it is necessary to identify which monitoring index best represents the surrounding rock damage. Currently, there are no advanced and convenient effectiveness evaluation schemes for surrounding rock monitoring information. To fill the technical gap, this study introduces the volume expansion rate (VER) index for surrounding rock and proposes a machine learning (ML)-based evaluation scheme for the effectiveness of monitoring indices. First, six conditions with different in situ stresses are designed, and tunnel excavation monitoring tests are conducted. Second, the surrounding rock damage determination experiments using the ML classification algorithm are performed, and the accuracy matrix and index significance scores are obtained. The evaluation results show that: (1) The multi-class logistic regression algorithm is more suitable for determining surrounding rock damage with high accuracy and more appropriate significance evaluation outcomes. (2) Under the higher in situ stress condition, the tangential stress is more sensitive to the surrounding rock damage. (3) As the in situ stress increases, the significant monitoring indices demonstrate a transition ‘from shallow to deep, from regional damage to point failure’, describing the instability of the surrounding rock and inspiring a new instability criterion for surrounding rock.

Core wall leakage is a common seepage-related defect occurring during the operation of core wall dams. Clarifying the characteristics and evolution of seepage field distortion under leakage conditions is an important basis for assessing dam safety status and evaluating leakage risks. In this study, short-duration, small-scale physical model tests of an asphalt concrete core wall dam were conducted under leakage heads of 14 cm (S1) and 20 cm (S2) to characterize the spatial response of the seepage field. Finite element simulations were subsequently validated against the experimental results and extended through parametric analyses of leakage channel widths of 1–10 mm and burial depths of 5–29 m. The experiments showed that the distortion profiles on horizontal sections were approximately semi-elliptical, with the maximum extent occurring at the elevation of the leakage center and progressively decreasing with vertical distance. The maximum dam-axis diffusion width increased from 9.00 cm under S1 to 11.05 cm under S2, while the maximum streamwise diffusion distance increased from 4.70 to 6.00 cm, corresponding to increases of 22.8% and 27.7%, respectively. Three-dimensional reconstruction further showed that the distorted region exhibited a quasi-semi-ellipsoidal morphology centered on the leakage location. Quantitative comparison between the experimental and numerical results yielded MAEs of 1.325 and 0.550 cm, RMSEs of 1.506 and 0.628 cm, and MAPEs of 18.01% and 13.90% for the dam-axis diffusion width and maximum streamwise diffusion distance, respectively, indicating that the numerical model captured the observed spatial response with moderate quantitative discrepancies. Engineering-scale simulations further showed that increasing leakage channel width generally enlarged the distorted region, whereas the effect of burial depth was non-monotonic and controlled by the downstream phreatic surface. Above the phreatic surface, seepage field distortion increased with leakage channel burial depth; once the leakage channel reached or extended below the phreatic surface, the distortion weakened with further increases in depth. These findings quantitatively characterize the spatial response of the internal seepage field to local core wall leakage and provide a physical basis for interpreting leakage-induced anomalies in seepage monitoring of core wall dams.