This study investigates the underlying causes of pier displacement and cracking in a highway link bridge. The initial geological assessment ruled out slope instability as a contributing factor to pier movement. Subsequently, a comprehensive analysis, integrating in situ soil investigation and finite element modeling, was conducted to evaluate the influence of additional fill loads on the piers. The findings reveal that the additional filled soil loads were the primary driver of pier tilting and lateral displacement, leading to a significant risk of cracking, particularly in the mid- of the piers. Following the removal of the filled soil, visual inspection of the piers confirmed the development of circumferential cracks on the columns of Pier 7, with the crack distribution closely aligning with the high-risk zones predicted by the finite element analysis. To address the observed damage and residual displacement, a reinforcement strategy combining column strengthening and alignment correction was proposed and validated through load-bearing capacity calculations. This study not only provides a scientific basis for analyzing the causes of accidents and bridge reinforcement but, more importantly, it provides a systematic method for analyzing the impact of additional filled soil loads on bridge piers, offering guidance for accident analysis and risk assessment in similar engineering projects.

Soil thermal conductivity (STC) plays a crucial role in regulating the energy distribution of both the surface and underground soil layers. It is widely applied in various fields, including engineering design, geothermal resource development and climate change research. A rapid and accurate estimation of STC remains a key focus in the study of soil thermodynamic parameters. However, the methods for estimating STC and their distinct characteristics have yet to be systematically reviewed. In this study, we used bibliometrics to comprehensively and systematically review the literature on STC, focusing on knowledge graph characteristics to analyze the development trend of calculation schemes. The main conclusions drawn from the study are as follows: (1) In recent years, most studies have been focused on soil thermal characteristics and their main contributing factors, the soil hydrothermal process in the Qinghai-Tibet Plateau, geothermal equipment and numerical simulations, and the exploration of geothermal resources. (2) A systematic review of various schemes indicates that no single scheme is universally applicable to all soil types. Moreover, a single parameterization scheme fails to meet the practical requirements of land surface process models. We evaluated the advantages and disadvantages of the traditional heat conduction schemes, parameterization schemes, and machine learning-based schemes and the findings suggest that a comprehensive scheme that integrates these three different schemes for STC simulations should be urgently developed.

This paper is based on the construction of the underground Pile-Beam-Arch station at Beitaipingzhuang Station of Beijing Metro Line 12. It employs finite element software for three-dimensional numerical modeling, faithfully reproducing the entire station construction process. The results indicate that the excavation of the pilot tunnel and the stage of the secondary lining buckle arch are the main causes of surface deformation. Additionally, the construction of the secondary lining buckle arch is the primary factor inducing deformation in the middle column and side pile. On this basis, the paper investigates the influence of four crucial factors: the stagger distance of the pilot tunnel excavation, the sequence of the secondary lining buckle arch, the excavation sequence of the lower soil, and the excavation depth on the stress and deformation characteristics of the stratum and the station structure. The results suggest that when the distance between adjacent pilot tunnel faces is 1.5 to 3 times the diameter of the pilot tunnel, it has the greatest influence on surface settlement. When the first side is followed by the middle, closely aligning the second lining with the initial support, and simultaneously installing buckle arches on both sides minimizes deformation of the stratum and station structure. During excavation of the lower soil in the station, reducing the single excavation depth and prioritizing excavation on both sides help control deformation of the vertical bearing structure. The optimal construction scheme is derived through multi-criteria optimization and implemented in the field. Field monitoring results are in good agreement with simulation outcomes, offering valuable reference for the construction of stations under similar geological conditions.

The Asiatic garden beetle, Maladera formosae Brenske (AGB), has become a significant pest of commercial mint fields in northern Indiana. Larval feeding on mint roots can cause stunted growth and plant death when densities are high. Sampling approaches that provide reliable estimates of larval densities in mint have not been established, leaving farmers without the knowledge necessary to implement integrated pest management (IPM) strategies. To address this knowledge gap, we evaluated strategies for estimating AGB larval densities and plant performance in commercial mint systems. We used 2 sampling methods to collect larval density and plant performance data from 3 mint fields and conducted simulations to optimize sampling intensity (accuracy and precision) and sampling scheme (random vs. systematic) using these data. Additionally, we examined the sensitivity and efficiency of each sampling method. Compared to the cup-cutter method, the quadrat method provided the most accurate and precise estimates of larval density and plant performance, with <= 7 samples required per 0.2 ha. Quadrat excavation was also more sensitive, increasing the probability of detecting AGB larvae within a 32 m2 plot by 76.7%, and requiring significantly less time to survey an equivalent volume of soil for AGB larvae. When the quadrat method was employed, random sampling schemes provided below-ground biomass estimates that were significantly closer to the true mean of the sampling area. The results of this research will facilitate the development of IPM decision-making tools for farmers and support future research for AGB and other soil insect pests affecting mint production.

This study proposes a rapid seismic resilience assessment framework of tunnels in mountain regions considering the topography amplification effect and tunnel-soil dynamic interaction based on the indirect boundary element method (IBEM) coupled with the finite element method (FEM). The high efficiency is achieved by using a surrogate model to determine the tunnel fragility curves. This model reflects the relationship between the geometric and material variables of mountains and tunnels, as well as the tunnel damage index. To obtain the surrogate model, the identification of model variables is first explored quantitatively based on the random forest algorithm due to the high variable quantity. The dataset for training and testing the random forest is constructed from 600 numerical simulations. The IBEM-FEM coupling scheme is employed to describe the large-scale site response for tunnel damage analysis and significantly reduce the number of finite element grids for each sample. This scheme solves the nonlinear dynamic response of mountain tunnels under near-fault earthquakes. The surrogate model is then used to obtain the tunnel functionality and resilience. Based on the proposed framework, the influence of the mountain material, mountain height-span ratio, and tunnel position on the seismic fragility, functionality, and resilience are investigated. The results reveal that a surrogate model can be employed to replace a series of nonlinear time-history analyses of tunnels, with a high accuracy and efficiency. The shear modulus of the surrounding rock, the height-to-span ratio of the mountain, and tunnel position have a significant impact on tunnel fragility and resilience. This impact is correlated with the tunnel height. The mountain topography can cause a difference of approximately 20 % in the tunnel resilience.

The low-velocity penetrator (LVP) is a planetary penetration device that can drive itself to a target depth through its internal periodic impacts. When LVP generates impact energy, it inevitably produces a recoil that can only be counteracted by friction with the soil, if there is no other auxiliary device. Unfortunately, LVP is extraordinarily sensitive to the recoil during the initial stage since the small contact area with the soil results in minor friction between them. Significantly, once the recoil exceeds the friction, LVP cannot work properly and may even retreat, inducing mission failure. In this paper, we develop an optimized LVP with an auxiliary device for lower recoil and higher performance. Specifically, we establish a dynamic model to analyze the single-cycle motion of LVP and provide essential support for its optimization and design. Meanwhile, an integration method is proposed to calculate the friction between LVP and the soil reasonably and accurately. On the basis of these, we obtain the optimal mass and stiffness parameters of LVP that meet both high penetration efficiency and low recoil. Furthermore, only relying on the parameter optimization is insufficient to eliminate the recoil, and an auxiliary penetration scheme is proposed to provide an external force counteracting the recoil until LVP arrives at a certain depth. Through multiple comparative penetration experiments, we validate the effectiveness of our approaches in promoting penetration ability, stability, and restraining the recoil of LVP. This work provides two novel approaches for solving the contradiction of efficient penetration while reducing the recoil for LVP.

Offshore wind turbines (OWTs) are affected by wind, wave, and current during their service life, which lead to the substructures undergoing combined effects of complex lateral loads and local scour. This phenomenon poses a significant challenge to the bearing capacity and cyclic responses of the widely used rigid monopiles for OWTs. This study develops three-dimensional numerical model to investigate the behavior of a rigid monopile subjected to lateral monotonic and cyclic loads, considering the stress history alteration induced by local scour. The hysteresis and plasticity accumulation of soils are captured by a bounding surface model. An accurate and concise semi-implicit stress integration scheme is creatively proposed to effectively incorporate this advanced constitutive model into the finite element (FE) software. The numerical model is verified by comparing FE results with centrifuge test results. Subsequently, the key factors such as cumulative deformation characteristics and bending moments distribution are investigated under different scour and cyclic loading conditions. The results indicate that with the facilitation of proposed semi-implicit scheme, the bounding surface model is capable of capturing the deformation pattern and cumulative deformation behavior of laterally loaded rigid monopile, and the cyclic responses of the monopile are significantly affected by the local scour.

Soil thermal conductivity (lambda), which describes the ability of the soil to transfer heat, is critical to understand the thermal regime of ground surfaces. In this study, in situ measurements of lambda were conducted at two field sites in the permafrost region of the central Qinghai-Tibet Plateau (QTP) and the results were used to evaluate 11 schemes of lambda at depths of 10-50 cm during the freeze-thaw cycle period. Our analyses revealed that lambda had a remarkable seasonal variation, due to the significant effects of soil moisture content and ice-water phase changes as temperature changed during the freeze-thaw cycle period. Among the selected schemes, the Johansen scheme, its three derivatives (i.e., the He scheme, Yang scheme and Zhao scheme), and the Campbell scheme were significantly superior to others. Moreover, the Johansen scheme ranked among the top schemes for frozen soil, while the Campbell scheme gave the most accurate values for unfrozen soil. The effects of different estimation methods of quartz content (q), dry lambda and the Kersten number (K-e) on the predicted schemes results were also evaluated. The results showed that, the methods used for the estimation of q and K-e had the greatest influence on the calculation results for the permafrost region. Overall, this research provides insights for the development of a lambda scheme for the permafrost region of the central QTP.

The representation of snow is a crucial aspect of land-surface modelling, as it has a strong influence on energy and water balances. Snow schemes with multiple layers have been shown to better describe the snowpack evolution and bring improvements to soil freezing and some hydrological processes. In this paper, the wider hydrological impact of the multi-layer snow scheme, implemented in the ECLand model, was analyzed globally on hundreds of catchments. ERA5-forced reanalysis simulations of ECLand were coupled to CaMa-Flood, as the hydrodynamic model to produce river discharge. Different sensitivity experiments were conducted to evaluate the impact of the ECLand snow and soil freezing scheme changes on the terrestrial hydrological processes, with particular focus on permafrost. It was found that the default multi-layer snow scheme can generally improve the river discharge simulation, with the exception of permafrost catchments, where snowmelt-driven floods are largely underestimated, due to the lack of surface runoff. It was also found that appropriate changes in the snow vertical discretization, destructive metamorphism, snow-soil thermal conductivity and soil freeze temperature could lead to large river discharge improvements in permafrost by adjusting the evolution of soil temperature, infiltration and the partitioning between surface and subsurface runoff.

With increasing global warming, the skiing season is shortened to different degrees all over the world. As a crucial way to ensure the sustainable development of the ski industry, snow storage has been gradually studied and applied in Europe. Covering thermal insulation materials is a key engineering measure for the success of snow storage. This study used numerical methods rather than an experimental method to evaluate the thermal insulation performance of nine snow storage coverage schemes in Harbin, Beijing, and Altay, China. We investigated the thermal insulation performance of nine snow storage coverage schemes (three natural materials and six artificial ones) using a solar radiation method and an implicit finite difference method. Sensitivity analyses were conducted, and the cost performance of schemes 5-9 were analyzed. Based on the cost and thermal insulation performance, we used schemes 4 (geotextile, straw bale), 5 (geotextile, extruded polystyrene foam), and 7 (geotextile, polyurethane foam) to evaluate the snow storage effects in Harbin, Beijing, and Altay. Results showed that among schemes 1-9, scheme 7 has the best thermal insulation performance. If natural materials are used, then scheme 3 gives the best thermal insulation performance. Among schemes 5-9, scheme 5 is the most economical. The heat transfer in Beijing is higher than that in Harbin and Altay, while the latter two show similar heat transfers. The combination of meteorological conditions and coverage schemes influence the melting rate of snowpacks. The melting rate of snowpacks can be reduced with an optimized coverage scheme. The proposed methods can serve the selection of coverage schemes for snow storage.