Empirical rainfall thresholds for predicting rainfall-triggered shallow landslides are proposed for Guangzhou city, which is prone to widespread geological hazards during the annual flood season due to the subtropical monsoon climate and frequent tropical storms and typhoons. In this study, the cumulated event rainfall (E, in mm), the duration of rainfall event (D, in day) (E–D) thresholds, normalized cumulated event rainfall, and the duration of rainfall event (EMAP–D) thresholds were defined. Thresholds based on five lithological units were obtained at 5%, 20%, and 50% probability levels using quantile regression methods. More than two-thirds of the landslides occurred within units of intrusive rock. The 20-day cumulative rainfall of 97 mm integrating cumulative event rainfall and the duration of rainfall events (CED) is introduced into the three-dimensional spatial threshold. The areas under the receiver operating characteristic curves for the CED threshold and E–D threshold were 0.944 and 0.914, respectively, and the true-positive rate of the CED threshold with the same probability level was slightly lower than that of the E–D threshold, but the CED threshold false-positive rate was much better than the E–D threshold, which can significantly reduce false alarm rate since many non-triggering rainfalls were filtered out.

Hydropower plants (including the switching station) built in the middle and southern section of the north–south zone of China are always situated in complex geological settings of transition zones from strong to weak earthquakes with active faults. It is of great importance to carry out careful evaluation of the slope stability considering various loading scenarios to ensure safe operation of the power stations. By using the rigid body limit equilibrium method and the finite element method, the effects of long-term load and seismic load on slope stability for a large hydropower station were studied. The results show that the slope safety factors of the station meet the stability requirements when the slope is under long-term load and under the action of the Wenchuan and Lushan earthquake loads. The stability of the slope is guaranteed. However, the risk analysis of the slope stability under the action of the design earthquake load shows that the slope safety factor is less than the accidental working condition safety factor of 1.05. Under the action of a strong earthquake, the crumbling block gravel soil layer in the shallow natural slope slides and destabilizes, which is obviously beyond its protection capacity, and therefore, effective seismic defense measures should be developed to ensure the safety of the personnel and equipment operating in the power station and switching station.

Tunnel excavation typically induces disturbance to the surrounding soil. Advance grouting using small-diameter pipes can effectively mitigate surface settlement. Taking the mine-method tunnel at the southern end of Xiancun Station on Guangzhou Rail Transit Line 18 as the research object, this paper uses the Midas GTS NX three-dimensional finite element (FE) software and adopts the upper-lower excavation method that prioritizes the formation of an upper support closed loop to simulate and analyze the impact of the CRD method on tunnel excavation under different grouting layer thicknesses. The research indicates that the surface settlement curve exhibits a “U”-shape. The settlement value decreases as the thickness of the grouting layer increases; when the thickness increases from 1.2 m to 2.0 m, the maximum surface settlement decreases from 12.87 mm to 9.09 mm, with successive reductions of 1.30 mm, 1.11 mm, 0.81 mm, and 0.56 mm, corresponding to rates of 10.10%, 9.59%, 7.67%, and 5.6%. Increasing the thickness of the grouting layer can effectively control surface settlement; however, when the thickness reaches 2.0 m, the stress distribution undergoes a change. Specifically, the compressive stress at the arch waist increases to 1683.01 kPa, and plastic failure occurs in the surrounding rock. By comparing the numerical results with field monitoring data, it is determined that when the grouting layer thickness is 1.4 m and the elastic modulus is increased by 30% based on that of the upper-soft soil, the model prediction shows the highest consistency with the actual effect. Furthermore, it is suggested that the grouting layer thickness be increased to 1.6 m. This study delivers a scientific foundation for the design of grouting parameters and the optimization of construction schemes for tunnels in composite strata and is of importance to improving tunnel construction technology in underground rail transit.

Geotechnical models are usually built upon assumptions and simplifications, inevitably resulting in discrepancies between model predictions and measurements. To enhance prediction accuracy, geotechnical models are typically calibrated against measurements by bringing in additional empirical or semiempirical correction terms. Different approaches have been used in the literature to determine the optimal values of empirical parameters in the correction terms. When measured data are abundant, calibration outcomes using different approaches can be expected to be practically the same. However, if measurements are scarce or limited, calibration outcomes could differ significantly, depending largely on the adopted calibration approach. In this study, we examine two most commonly used approaches for geotechnical model calibration in the literature, namely, (1) purely data‐catering (PDC) approach, and (2) root mean squared error (RMSE) method. Here, the purely data‐catering approach refers to selection of empirical parameter values that minimize coefficient of variation of model factor while maintains its mean value of one, based solely on measured data. A real case of calibrating the Federal Highway Administration (FHWA) simplified facing load model for design of soil nail walls is illustrated to thoroughly elaborate the differences in practical calibration and design outcomes using the two approaches under scarce data conditions.

In civil engineering projects, the practice of partial excavation or backfilling of slopes often results in landslide occurrences because of the redistribution of internal stress within the slope mass. This paper presents the findings from scaled-model tests conducted to investigate the reinforcement of high-fill embankment slopes using anti-slide piles. During the filling process, data were meticulously monitored using strain gauges affixed to the pile bodies and embedded earth pressure cells. The analysis focused on the mechanical behavior, including load–displacement relationships at the pile tops, bending moments, and earth pressures. This study was designed to investigate how anti-slide piles contribute to slope stabilization and to evaluate their load-bearing behavior throughout the backfilling process. Additionally, particle image velocimetry technology was used to capture the variation patterns of the soil surface displacement field, thereby revealing soil displacement deformation and the overall failure mechanism. By integrating mechanical responses with the analysis of the soil displacement field, a more profound understanding of the pile–soil interaction mechanism was attained. This experimental method provided a comprehensive depiction of the entire process, from the initial slope movement to its eventual deformation and failure. The research indicates that a reduction in pile spacing leads to a decrease in the maximum bending moment of the pile body, thereby enhancing slope reinforcement. For the same pile spacing, the pile located on the first-level slope platform shows the smallest horizontal displacement at its top after deformation. The soil on either side of the anti-slide pile disperses outward from the pile body, with the maximum displacement occurring directly beneath the pile tip.