Kun Liu

In 2013, a Ms 6.6 earthquake occurred at the boundary of Min County and Zhang County, triggering numerous landslides. Notably, two landslides with significantly different sliding characteristics emerged less than 100 m apart in Yongguang Village, Min County. The eastern landslide was characterized by instability induced by seismic inertial forces, whereas the western landslide exhibited flow slides triggered by liquefaction in loess. To further analyze the causes of these landslides, this study employed a 1 m depth ground temperature survey to probe the shallow groundwater in the area, aiming to understand the distribution of shallow groundwater. Based on the results from the 1 m depth ground temperature survey, a random forest model was applied to regressively predict the initial groundwater levels. The TRIGRS model was utilized to evaluate the influence of pre-earthquake rainfall conditions on landslide stability, and the pore water pressure outputs from TRIGRS were integrated with the Scoops3D model to analyze landslide stability under seismic effects. The results indicate that the combination of the 1 m depth ground temperature survey with high-density electrical methods and random forest approaches effectively captures the initial groundwater levels across the region. Notably, the heavy rainfall occurring one day prior to the earthquake did not significantly reduce the stability of the landslide in Yongguang Village. Instead, the abundant groundwater in the source area of the western landslide, combined with several months of pre-earthquake rainfall, resulted in elevated groundwater levels that created favorable conditions for its occurrence. While the primary triggering factor for both landslides in Yongguang Village was the earthquake, the distinct topographic and groundwater conditions led to significantly different sliding characteristics under seismic influence at the same slope.

To investigate the distinctive characteristics of deformation and internal force variations in frame beam anchor structure supporting frozen soil slopes during freezing-induced frost heave, a comprehensive three-dimensional finite element model was developed. This model, utilizing the Winkler elastic foundation beam theory, is engineered to examine frost heave occurrences in frame anchor structures during freezing periods. The frame beam is modeled as a homogeneous elastic Euler-Bernoulli continuous beam, while the frozen soil behind the slope is represented through simplified pre-compressed soil springs. Simultaneously, based on the heat conduction differential equation during the phase coexistence of solid and liquid in the freezing-expansion process, the freezing expansion distribution force acting on the frame beam is obtained. By employing MATLAB programming and leveraging existing engineering cases, customized calculation programs were developed and compared against numerical simulation outcomes. The findings underscore the efficacy of the proposed method in accurately portraying the free frost heave displacement of frozen soil on slopes. Lateral displacements and bending moments obtained through this approach are consistently aligned with the results of numerical simulations. Moreover, the proposed calculation method offers a swift means of assessing frost heave displacement and the stress state of frame anchor structures, requiring only a minimal set of parameters. The research outcomes not only present a comprehensive insight into the three-dimensional dynamics between frozen soil and frame anchor support structures but also provide invaluable scientific guidance for designing frame anchor slope structures in cold regions.

In recent years, the earthen ruins’ cultural relics have aroused people’s extensive attention, and the protection of them is more and more urgent. The aim of the paper is to present the essential results of an ongoing research on a reinforced rammed earthen wall in the Suoyang ancient city (Guazhou, China). A variety of methods to combining aerial survey, dynamic test, and numerical model is provided with the purpose of estimating the structural characteristics of the ancient rammed wall. An aerial geometric survey based on high-resolution images made by unmanned aerial vehicle (UAV) has been approached to acquiring a 3D model. An ambient vibration test has been adopted by using vibration pick-ups. The experimental data were dealt with the operational modal analysis (OMA) followed by comparing with the numerical results delivered by the model. Meanwhile, the results showed the maximum displacements and corresponding positions of the structure under the three modes by the finite element model (FEM).

The protection of earthen sites plays an important role in the context of preservation of cultural heritage, especially in the inheritance and promotion of history and culture. The aim of the paper is to present the essential results of an ongoing research on a reinforced rammed earthen wall in Suoyang City (Guazhou, China). The wall vibrations caused by ambient actions were analyzed using the stochastic subspace algorithm to estimate the modal parameters of the wall. The frequencies of the first three orders are 3.566 Hz, 5.003 Hz, and 6.250 Hz, and the corresponding modes are first‐order transverse bending, second‐order left and right torsion, and third‐order vertical bending, respectively. Then, according to the data of elastic modulus obtained in the lab, the finite element calculation is carried out, and referring to the results of field measurement, the revised elastic modulus value is 205.90 MPa. It is worth mentioning that the revised value is significantly improved from the original laboratory value, and it is also indicated that the seismic performance of the reinforced wall has been significantly improved. The present work is expected to provide a theoretical basis for reinforcement, protection, and seismic control of earthen ruins.

What the role of each phase medium plays and how their interactions do work should be essential problems to understand dynamic behaviours of soils. In order to disclose interactions between solid, water, and air phases of soils, we applied loess samples to analyse controlling effects of residual deformation on pore pressure based on three kinds of laboratory tests. We obtained the similarity and difference of mechanical behaviors of soil samples under different water contents and loading. Both process and cause of pore air/water pressures are independent of initial stress conditions or loadings. However, absolute values of pore water pressure depend on the confining pressure, whereas the pore air pressure is contrary. The uniformity of responding process and cause of pore pressure depend upon the interaction mechanism between solid particles and air/water media, but the different absolute values depend upon the permeability and compressibility of air/water.