Infilling fractured rock masses are widely distributed in the deeply buried oil reservoirs and surrounding rocks of mine caves. The internal filling material has a great influence on the mechanical properties and seepage characteristics of fractured rock mass. In this paper, through theories and experiments, the mechanism of permeability changes of infilling fractured rock under a coupling condition is studied. In terms of theory, the fracture compaction effect coefficient δ is added to the classical matchstick model, and the volume strain principle is used to propose a permeability model for fractured rock. Furthermore, based on the Hertz contact theory, mineral particles are generalized into rigid spheres, and the mechanism of crack development between mineral particles under seepage pressure is analyzed. In terms of experiment, a true triaxial seepage test was carried out on rock-like specimens to obtain the change law of the permeability characteristics of fractured rock. The test results are largely consistent with the theoretical calculation results of the theoretical model, which verifies the applicability of the model proposed in this paper. After the loading failure of the specimen, the internal filling material was taken out and analyzed, and by observing the distribution of cracks on the surface, it is verified that the seepage pressure promotes the development of cracks in the filling fracture.

Fault-crossing tunnels are often severely damaged under seismic dynamics. Study of the dynamic response characteristics of tunnels crossing faults is thus of great engineering significance. Here, the Xianglushan Tunnel of the Central Yunnan Water Diversion Project was studied. A shaking table experimental device was used, and four sets of dynamic model tests of deep-buried tunnels with different fault inclination angles were conducted. Test schemes of model similarity ratio, similar material selection, model box design, and sine wave loading were introduced. The acceleration and strain data of the tunnel lining were monitored. Analysis of the acceleration data showed that when the input PGA was 0.6 g, compared with the ordinary tunnel, the acceleration increases by 117% when the inclination angle was 75°, 127% when the inclination angle was 45°, and 144% when the inclination angle was 30°. This indicates that the dynamic response of the cross-fault tunnel structure was stronger than that of the ordinary tunnel, and the effect was more obvious as the fault dip angle decreased. Analysis of the strain data showed that the strain response of the fault-crossing tunnels was more sensitive to the fault dip. The peak strain and increase in fault-crossing tunnels were much larger than those of ordinary tunnels, and smaller fault dips led to larger increases in the strain peak; consequently, the tunnel would reach the ultimate strain and break down when the input PGA was smaller. Generally, the influence of fault inclination on the dynamic response of the tunnel lining should receive increased consideration in the seismic design of tunnels.

Water resources and energy constitute two broad categories of resources required for social and economic development. The water-energy nexus has become a focus of research in recent years. Although water resources are closely related to energy systems, the processes involved remain incompletely understood due to the diversity and complexity of energy types, processes, and consumption sectors. This study aimed to accurately calculate the energy demand of water resources and to identify an effective method of improving the energy utilization efficiency of water. The life cycle of water resources was divided into five stages based on the life cycle methodology: (1) extraction, (2) purification, (3) transportation, (4) utilization, (5) sewage treatment. The quantity and characteristics of energy consumed in each stage were studied, and an equation to calculate energy consumption for each stage was proposed. Using the city of Ordos in Northwest China as an example, energy consumption of water resources from 2013 to 2017 was analyzed. The results showed that from 2013 to 2017, energy consumption and per unit energy consumption of water resources in Ordos decreased by 33.3% and 30.6% from 1.62 × 10⁸ kWh to 1.08 × 10⁸ kWh and from 10.11 kWh·m⁻³ to 7.02 kWh·m⁻³, respectively. The majority of energy consumption over the entire life cycle of water resources occurred during the utilization stage at a proportion of total energy consumed of ~95%. Use of water for thermal power generation was identified as the single largest consumer of energy and, therefore, has the greatest potential for energy saving.