Uneven displacement of permafrost has become a major concern in cold regions, particularly under repeated freezing-thawing cycles. This issue poses a significant geohazard, jeopardizing the safety of transportation infrastructure. Statistical analyses of thermal penetration suggest that the problem is likely to intensify as water erosion expands, with increasing occurrences of uneven displacement. To tackle the challenges related to mechanical behavior under cyclic loading, the New Geocell Soil System has been implemented to mitigate hydrothermal effects. Assessment results indicate that the New Geocell Soil System is stable and effective, offering advantages in controlling weak zones on connecting slopes and reducing uneven solar radiation. Consequently, the New Geocell Soil System provides valuable insights into the quality of embankments and ensures operational safety by maintaining displacement at an even level below 1.0 mm. The thermal gradient is positive, with displacement below 6 degrees C/m, serving as a framework for understanding the stability of the subgrade. This system also enhances stress and release the sealing phenomenon.

The distinct particle breakage characteristics of calcareous sand can induce extra settlement in calcareous sand foundations, posing a significant challenge to the safety of island and reef engineering. To explore the particle breakage, settlement characteristics and internal stress variations of calcareous sand foundations, the laboratory loading tests for calcareous sand foundations with different particle gradations were conducted. Particle Image Velocimetry (PIV) technology and tactile pressure sensor systems were also utilized. The study reveals that the tested calcareous sand foundations have differential settlements subjected to external loading, which has a strong relationship with the particle breakage. It is found that the nonuniform internal stresses between the sand particles can induce different degrees of the particle breakage, which in turn changes internal stresses and redistribution of particle positions in calcareous sands, and further causes the uneven settlement of the foundation. The degree of uneven settlement in calcareous sand foundations increases with an increase of external load and decreases with an increase of the coefficient of uniformity Cu for calcareous sands. During creep, the vertical and lateral stresses on the inter-particle contacts within the calcareous sand foundation exhibit an overall trend of decrease in weak forces and increase in strong forces. This continuous increase in strong forces results in a growth of creep deformation in calcareous sand foundation, while the degree of differential settlement in the foundation decreases with the progression of creep.

Taking a caisson foundation engineering of a railway across-river bridge as the case, the technical characteristics and key challenges of over-deep inclined caisson were described firstly. Subsequently, the main controlling factors of the uneven settlement were analyzed. In view of the difficulty in obtaining the parameters of disturbed grouting soil, as well as the large adjustment of subsequent construction loads, an uneven settlement method based on over-deep underwater lateral pressure test and high-pressure consolidation test was proposed. The proposed method was simulated by finite element method to analyze the variations of total settlement, differential settlement and inclined attitude of caisson foundation under different loading stages. The results showed that the difference in the thickness of the disturbed layer was the dominant factor of uneven settlement, finally controlling the inclination shape. Grouting reinforcement was conductive to improving the settlement of caisson foundation. The maximum total settlement, differential settlement and offset after reinforcement were reduced to 249.53 mm, 19.54 mm and 29.20 mm, respectively. The deformation mainly occurred in the loading stage before the platform construction, accounting for about 60 %. If it is considered to level the top surface, adjust the elevation and load center during the construction of platform, the incremental settlement, the north-south differential settlement and the offset of top surface corresponded to 94.26 mm, 10.31 mm and 17.52 mm, respectively. Finally, the reliability of above method was fully verified by comparing the measured data with calculated value. The results will provide certain ideas and methods for relevant engineering problems. (c) 2024 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Society. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

In this paper, uneven-aged stands from two important Romanian mountain areas-the Southern Carpathians and Banat Mountains-are compared with the purpose of studying the stationary conditions of uneven-aged forest stands in order to determine which management strategies are best suited to these forests and other Romanian forests with a similar structure. The study is based on silvicultural practices and natural growth conditions related to uneven-aged forest stands. The analysed surface represents 20% of Romania's forests and includes all uneven-aged forest stands in the Southern Carpathians and half of the Romanian Western Carpathians. It has been concluded that the Southern Carpathians and Banat Mountains contain a relatively reduced percentage of uneven-aged stands compared with the total number of stands due to their composition and less favourable stationary conditions of the stands. This highlights the novelty of the work carried out in this study on uneven-aged forest stands from two landscape reliefs in Romania.

The soil layer of the roadbed is an uneven unsaturated soil layer in practical engineering. The goal of this article is to consider the uneven gradient distribution of soil particle compression modulus and soil skeleton compression modulus along the depth of unsaturated roadbed soil. Introducing an uneven gradient factor is to propose a power function continuous variation model for the soil particle compression modulus and soil skeleton compression modulus of the roadbed soil along the depth of the soil layer. Then, the model is coupled with Biot's theory of unsaturated porous media to establish a dynamic response model for non-uniform unsaturated soil layer roadbed under uniform moving loads, and provided a method for using Fourier series to solve the model. Analysis the influence of soil particle compression modulus and soil skeleton compression modulus on the dynamic response of unsaturated soil layers under uniform moving loads. The results indicate that the deformation displacement is positively correlated with the non-uniform gradient factor of modulus. The deeper the depth, the weaker the influence of the non-uniform gradient factor on the peak pore water pressure. At the same location from the vibration source, the influence of the non-uniform gradient factor of soil particle compression modulus on the peak pore water pressure is not significantly different from the influence of soil skeleton compression modulus on the peak pore water pressure. However, the gradient factor of soil particle compression modulus has a greater impact on the peak deformation displacement than the factor of skeleton compression modulus. Thus, clarified the influence of the non-uniform gradient factor of soil particle compression modulus and soil skeleton compression modulus along depth on the dynamic response of the non-uniform unsaturated soil layer roadbed under uniform moving load.

Uneven settlement phenomenon is very easy to occur in the sandy pulverized ground stratum, the underground pipe corridor longitudinal and transverse stiffness difference is obvious, so that it is easy to crack and deformation due to uneven settlement in this type of stratum. This paper carries out research on uneven settlement and cracking and deformation of Qihe tube corridor, analyzes the reasons leading to uneven settlement and the factors affecting the deformation and cracking of the tube corridor, and provides guidance for foundation treatment and tube corridor repair and mixing and reinforcement. It was found that the concrete structure of the corridor itself had exposed reinforcement, pockmarks and holes, and that cracks on the structure of the corridor sprouted and expanded from these defects. Defects and damages on the concrete structure of the pipeline corridor are contributing factors to the deformation and cracking of the members, and the uneven settlement of the foundation is the main initiating factor for the cracking and deformation. The analysis of the numerical simulation results of similar underground pipeline corridors is carried out, and it is found that the simulation results are consistent with the deformation characteristics of the Qihe pipeline corridor, which further supports the conclusions of this paper. The main stratigraphic factors contributing to the inhomogeneous settlement were found to be the water-rich and loose bodies in the lower part of the strata, as revealed by the physical means and the experimental verification boreholes. Localized hydraulic effects such as pumping further accelerate the uneven settlement of the foundation.