The sliding process of the landslide is gradual, and it is impossible for all points on the sliding surface to be in the state of peak shear stress. Therefore, it is reasonable and necessary to consider the stability calculation of the progressive failure process of landslide. In view of the existing stability analysis methods considering progressive failure of landslides, it is unreasonable to define key blocks incorrectly and adjust sliding surface parameters at different stages to consider the stress softening phenomenon of soil mass, which causes damage to the continuity of shear stress and strain curve of soil mass. To more closely consider the progressive process of landslide failure and more accurately describe the different stress states of each point on the sliding surface, the concept of landslide key block is proposed. The concept of the key block of landslide is put forward, and the displacement of landslide is introduced into the stability analysis of landslide by a new shear stress model. Based on the unbalanced thrust method, a new displacement-resistance method (NDR) is established, and the calculation formula of landslide stability is given.
To obtain the precise calculation method for the peak energy density and energy evolution properties of rocks subjected to uniaxial compression (UC) before the post-peak stage, particularly at sigma >= 0.9 sigma(c) (sigma denotes stress and sigma(c) is the peak strength), extensive UC and uniaxial graded cyclical loading-unloading (GCLU) tests were performed on four rock types. In the GCLU tests, four unloading stress levels were designated when sigma = 0.9 sigma(c). The variations in the elastic energy density (u(e)), dissipative energy density (u(d)), and energy storage efficiency (C) for the four rock types under GCLU tests were analyzed. Based on the variation of u(e) when sigma >= 0.9 sigma(c), a method for calculating the peak energy density was proposed. The energy evolution in rock under UC condition before the post-peak stage was examined. The relationship between C-0.9 (C at sigma >= 0.9 sigma(c)) and mechanical behavior of rocks was explored, and the damage evolution of rock was analyzed in view of energy. Compared with that of the three existing methods, the accuracy of the calculation method of peak energy density proposed in this study is higher. These findings could provide a theoretical foundation for more accurately revealing the failure behavior of rock from an energy perspective. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).
This study introduces a simplified analytical method to extract shear wave velocity profiles from seismic waves evoked by explosives, providing a time-efficient solution to the conventional Multichannel Analysis of Surface Waves (MASW) method. Controlled ammonium nitrate emulsion explosions were used at five research sites throughout Thailand with different geological conditions to capture ground motion data through a 16-geophone array during field investigations. This direct analysis evaluates surface wave arrival times in real-time while implementing elastic theory-derived empirical factors for analysis. The proposed method delivers results that match MASW-derived profiles yet require fewer complex procedures and shows Vs30 variations from 4.43 to 38.33%. The simplified method delivered the most accurate results in areas displaying gradual soil property transitions and showed reduced precision when dealing with abrupt soil type or mechanical property shifts. The new method transforms petroleum exploration seismic data into geotechnical applications by delivering dependable shear wave velocity profiles with lower complexity and using fewer resources. It is specifically valuable for limited-budget engineering projects or difficult-to-access locations.
Accurate prediction of excavation deformation and stress affects the safety of excavation engineering and the surrounding environment. However, the traditional calculation method ignores the influence of soil shear action and its nonlinear deformation characteristics. Therefore, this paper proposed a coupled analytical method for braced excavation considering the continuity of soil deformation and nonlinear pile-soil interaction. A nonlinear Pasternak two-parameter foundation model was developed based on the Pasternak foundation model and nonlinear p-y curves. The control differential equations for the excavation in the critical and embedded sections were derived. Also, the numerical solutions of excavation deformation and force under different boundary conditions were obtained by the finite difference method and Newton's iteration method. Further, the excavation calculation procedure considering the construction process and nonhomogeneity of soil was suggested. Through finite-element (FE) and engineering case analyses, the traditional calculation method overestimated the excavation deformation and internal force, while the proposed methods were consistent with the measured results. Finally, the effects of soil shear stiffness and initial foundation reaction modulus on the excavation were discussed, and we found that the two parameters had more significant impact on the wall bending moment than displacement. The results provide some reference for the design calculation of braced excavation.
In loess slopes, landslides are easily caused by rainfall and can be prevented by using retaining structures of stabilizing piles. This paper investigated the deformation and mechanical behaviors of the cantilever and fully buried stabilizing piles under complex pile-soil interactions. The deformation and mechanical behaviors, failure modes, and soil pressure distributions of two types of stabilizing piles were analyzed based on field model tests. Further, a calculation method for stabilizing piles considering nonlinear pile-soil interactions was proposed. Also, the numerical solution of the pile deformation and force was obtained by using the finite difference method and Newton's iterative method. The results showed that the deformation and mechanical behaviors of fully buried piles are superior to those of cantilever piles. Fully buried piles and cantilever piles have plastic double-hinged and single-hinged failure modes and undergo bending damage and shear damage, respectively. Besides, the landslide thrusts and soil resistances acting on the pile showed a parabolic distribution pattern. Compared to the model test results, the traditional calculation method overestimated the deformation and internal force of the stabilizing pile by 37.32%, and the newly proposed calculation model considering nonlinear pile-soil interactions was more consistent with the measured values. The study results help to guide the design and calculation of stabilizing piles under complex pile-soil interactions.