Tong Jiang’s research while affiliated with North China University of Water Resources and Electric Power and other places

The long-term stability of slopes in areas with strong earthquakes not only is very important for people’s lives and the safety of property, but also it enables restoration of the ecological environment in the landslide areas, which is very important for sustainable development. The most commonly used seismic-support method, anti-slide piles, provides outstanding seismic performance. However, piles still deform and fail during earthquakes, which can lead to instability of the slope. The dynamic response of a slope reinforced with anti-slide piles is crucial for maintaining the long-term stability of the slope in a strong-earthquake area and, thus, for promoting its sustainable development. However, current research is focused mainly on the stability of the slope, and there have been few studies on the dynamic response of anti-slide piles. For this reason, we have undertaken the present study of a bedding-rock slope supported by a single row of anti-slide piles. By changing the frequency, amplitude, and duration of the input seismic waves, we have systematically explored the influence of their spectral characteristics on the dynamic response of the anti-slide piles and the slope using numerical simulations combined with the wavelet-transform method. Our results show that the spectral characteristics of the seismic waves significantly affect the deformations of the anti-slide piles. Low-frequency and high-amplitude seismic waves have stronger destructive effects on slopes, and high-amplitude seismic waves can generate multi-level sliding surfaces that extend to deeper levels. The low-frequency component of the seismic wave controls the overall deformation of the slope, and the high-frequency component controls the local deformations. An increase in the proportion and duration of low frequencies in seismic waves is the main cause of slope deformation and failure. The present work, thus, provides a useful reference for the design of a slope supported by anti-slide piles in an area with strong earthquakes, as well as for the maintenance of the long-term stability of such a slope, therefore, encouraging the sustainable development of related areas.

The tailwater tunnel of the Wuyue pumped storage power station is located in bedrock and extends to depths between tens and hundreds of meters. It is impossible to analyze and evaluate the whole engineering area from geological exploration data, and the hydrogeological conditions are complicated. In the early stages of the tailwater tunnel’s construction, the drinking water wells in four villages dried up. This paper reports the results from a field investigation, in situ tests, laboratory tests, and numerical simulation carried out to determine how the groundwater was affected when the tunnel was excavated. A hydrogeological model of the region was established from the inverted regional natural flow field parameters. The model was validated, and an analysis of the errors showed that there was an average error of 1.98% between the natural flow field and the hydrogeological survey flow field. The model was then used to simulate the three-dimensional transient seepage fields under normal seepage conditions and limited seepage conditions, as far as was practical. The results showed that, as the excavation of the tailwater tunnel advanced, the water inflow to the tunnel also increased. When the water inflow increased from 1000 to 5000 m³/d, the water level at a distance of 100 m from the axis of the tunnel dropped from −0.956 to −1.604 m. We then analyzed how the water level changed as the water inflow varied and proposed a formula for calculating the extent of the influence on the groundwater. We studied how the water level changed at different well points to ascertain how a groundwater well became depleted and determined the factors that influenced seepage in the regional flow field. The water level in different areas of the project area was simulated and analyzed, and the extent of the groundwater area affected by the tunnel construction was clarified. We then studied how the groundwater in different areas of, and distances from, the project area was influenced by normal seepage conditions and limited seepage conditions and proposed a formula for calculating the extent of the influence on groundwater for different water inflows. We constructed a ‘smart site’ for visualizing data, sharing information, and managing the project. Time–frequency domain analysis was applied to explore the extent of the impacts and range of the vibration effects on residential housing at different distances from the project area caused by the different methods for excavating the tailwater tunnel. The results from this analysis will provide useful insights into how the excavation of this tailwater tunnel will impact the local residents and living areas.

Understanding the brittle fracture behavior of rock is crucial for engineering and Earth science. In this paper, based on acoustic emission (AE) and laser Doppler vibration (LDV) monitoring technology, the staged damage behaviors of rock-like materials with different brittleness degrees under uniaxial compression are studied via multiple parameters. The results show that the brittleness degree determines the fracture mode. As the specimen’s brittleness degree increases, the tensile failure increases and shear failure decreases. AE activity is enhanced at the crack damage point. With an increasing specimen brittleness degree, different instability precursor information is shown during the unstable crack growth stage: the AE b value changes from the fluctuating to continuously decreasing state, and the natural frequency changes from the stable fluctuation to upward fluctuation state. The AE b value near the stress drop is the smallest, and it decreases with an increasing brittleness degree. The natural frequency reduction indicates the rock-like fracture. The natural frequency is a symbolic index that reflects staged damage characteristics and predicts the amount of energy released by brittle failure. These findings provide guidelines for rock stability monitoring and provide support for better responses to stability evaluations of rock slopes, rock collapses, and tunnel surrounding rock in engineering.

In this paper, the changes in the pressure arch height above the tunnels subject to earthquake were analyzed by using theoretical, numerical, and experimental ways, respectively, and then, a corresponding formula was derived. The phenomenon of stress rotation and pressure arch around the tunnel under earthquake was found by illustrating the stress vector around tunnel. The force transmission method was used to analyze the change in pressure arch height of rectangular, horseshoe-shaped, and circular tunnels before and after earthquake, and then, a new method was presented to determine the pressure arch height above the tunnel under earthquake according to stress changes in surrounding rock. Then, the two methods were jointly used to analyze the pressure arch height above the tunnel. The results show that the tunnel shape has great effect on the shape of pressure arch, and the pressure arch height of deep tunnel varies little with depth. The changes in the shape and height of tunnel pressure arch before and after earthquake obtained from theoretical analysis and numerical simulation were finally verified by shaking table model tests. The research results in this paper may provide practical significance in seismic design of tunnel structures.