bluuebunny/crossref_metadata_2025 huggingface dataset:
Parameter sensitivity analysis of peak impact force for an actual flow-like landslide against a single rigid barrier
Authors: Zhang W J , Hong X Y , Zhang W , Wang X , Chen S X
Published: May 2024

Strength parameters are key factors that influence the sliding process of landslides and further affect the impact force on structures. Many scholars have previously studied the influence of strength parameters on slope stability; however, the influence of strength parameters on the impact force of flow-like landslides has not been analyzed till date. Therefore, in this study, the smoothed particle hydrodynamics (SPH) method was used to simulate the flow process of landslides and estimate the impact force on the rigid barrier by adjusting the strength parameters of landslides. The proposed SPH model was validated by a model test of dry sand impacting rigid barriers. The Gaoloucun landslide was selected as the study case and simulated to study the influence of parameters on the impact force. Finally, a multiple linear regression analysis was conducted to explore the sensitivity of impact force to input parameters and obtain the standardized regression coefficient, which was compared to find the dominant strength parameter. According to the results, among two strength parameters, the internal friction angle has more influence on the peak impact force than the cohesion.
A slope management method by monitoring soil volumetric water content and its validation through numerical analysis
Authors: Yoshida S , Xiong X , Muramatsu R , Fukada S , Matsumoto T
Published: May 2024

Landslides induced by heavy rainfall have become increasingly common in recent years. As the groundwater level rises, the safety factor of slopes tends to decrease. However, traditional monitoring methods, such as employing water-level (pressure) gauges in boreholes, require significant effort. Thus, this study proposes a slope management approach based on monitoring the volumetric water content of the ground surface. The monitored slope, approximately 20 m in height and 30 m in length, consists of topsoil mixed with grass roots and sand with a slight silt admixture, as revealed by two borehole investigations. Soil moisture meters were strategically installed at three locations along the slope (upper, middle, and lower sections) to gauge the volumetric water content. Observations indicated a sensitive increase in ground water content following rainfall. Furthermore, a three-dimensional Finite Element Method (FEM) analysis was employed to explore the correlation between rainfall (intensity and duration) and groundwater content. The FEM analysis also examined the impact of rainfall-induced changes in slope water content on the overall slope safety factor, utilizing 3D point cloud data to model the monitored slope. Qualitative agreement was observed between the monitoring and analysis results, highlighting a decrease in slope safety factor as slope water content increased. These findings underscore the potential of conveniently assessing slope safety factors based on the water content of a slope’s ground surface.
Landslide Susceptibility Mapping Using Machine Learning: A Case Study of Oregon
Authors: Wu Bin , Shi Zhenming , Peng Ming
Published: May 2024

Landslide susceptibility assessment, a crucial component of disaster prevention and mitigation, has traditionally relied on geological datasets and commonly used evaluation metrics. However, these metrics, often applied to 2D susceptibility maps, may not capture the full complexity of the issue. In this study, we incorporated spatial distribution data, including a historical landslide inventory, and integrated morphological, geological, hydrological, and land-use features. This approach enabled the construction of predictive models using eight distinct algorithms. The evaluation of classifier performance scores unveiled the superior performance of gradient tree boosting. In contrast, logistic regression struggled to handle the nonlinear aspects of landslide susceptibility analysis. A finding in our research was the consistent disparity in predictive susceptibility maps, even when similar performance scores were achieved across different algorithms. This underscores the necessity of combining evaluation metrics with spatial mapping in landslide susceptibility model assessment. We also highlighted the critical role of digital elevation models in constructing effective models when feature data was limited. Conversely, when abundant information was available, the integration of multi-source data significantly enhanced the precision of landslide susceptibility mapping. Overall, this study provides valuable insights for spatial prioritization in landslide field investigations and enhances our understanding of landslide risk assessment.
Influence of frequency characteristics of seismic ground motion on the fragility of an RC frame structure
Authors: Fei Yang , Chen Longwei , Lei Jinhui
Published: May 2024

Ground-motion frequency characteristics have a significant impact on structural damage. A quantitative description of the impact of ground-motion spectral features on structures is an urgent topic that requires solutions. In this study, the ratio of peak displacement to peak acceleration (R
d2a
) is used as a representative index of the ground-motion spectral characteristics. The seismic records collected from the Kik-net strong-motion array in Japan are grouped according to their R
d2a
values. By adopting the incremental dynamic analysis method, the seismic fragility curves of a six-story RC frame structure loaded by inputting seismic records with different R
d2a
values are calculated using the OpenSees platform. The influence of R
d2a
values on the structural fragility is analyzed. Ground-motion records of liquefied sites are collected, and the peak ratios of seismic records at the liquefied sites are analyzed to reveal the differences in the fragility of the six-story RC structures at liquefied and non-liquefied sites. The results of this study are expected to serve as a reference for the evaluation of structural fragility and to understand the effect of ground-motion frequency characteristics on the fragility of RC frame structures.
Influence of clay content on repeated liquefaction resistance of sand using element test
Authors: Zhong Y , Ni X , Zhang S
Published: May 2024

Soil liquefaction is a major concern because of its potential to cause building collapse, roadbed settlement, and sand eruptions. Field investigations have shown that clayey sand, when liquefied during mainshock, may undergo multiple liquefaction events during the subsequent aftershocks. Although previous research has primarily focused on the initial liquefaction event in clayey sand, research on the mechanism responsible for repeated liquefaction is limited. Consequently, a series of cyclic triaxial experiments are conducted on sand with varying clay contents, and these samples are subjected to various earthquake sequences. The primary objective of this study is to evaluate the cyclic behavior of sandy soil with clay content and analyze its repeated liquefaction resistance under different load sequences. A comprehensive assessment is conducted to understand the evolution of the repeated liquefaction resistance. The test results indicate that clayey sand exhibits the lowest liquefaction resistance during the second liquefaction event. Repeated liquefaction is dominated by stress-induced anisotropy at earlier events and relative density at the final events.
Evaluation of large axial strain of granular sand in post-liquefaction stage using DEM simulation
Authors: Ma Junnan , Ni Xueqian , Zhang Feng
Published: May 2024

Field investigations in recent studies have revealed that significant damage to foundations often occurs in the post-liquefaction stage, during which sand undergoes substantial deformation. As a result, numerous researchers have dedicated considerable effort to studying the evolution of the axial strain at this stage. However, the accurate measurement of the exact value of this strain is challenging mainly owing to the limitations of the triaxial apparatus. In this study, the numerical method of discrete element method (DEM) is used to simulate undrained cyclic triaxial loading tests according to a large number of loading cycles. The mechanical behaviour of granular sand under different cell pressures was reproduced using the DEM method, wherein the liquefaction resistance increased with the cell pressure. The post-liquefaction axial strain exhibited a similar pattern of variation among the calculated cases at different cell pressures. The value of the double amplitude of the axial strain stabilised at a maximum value after a certain loading cycle. The microscopic characteristics derived from the DEM calculations, including the contact number and force chain network, were analysed to provide reasonable explanations. The sand fabric was re-established after a large number of loading cycles and controlled by cyclic loading, which helped stabilise the accumulated axial strain.
Screening effect of pile rows for ground vibration induced by moving loads
Authors: Yang S , Jia M C
Published: May 2024

This study aims to predict the screening efficiency of pile rows in transversely isotropic (TI) saturated soils for ground vibrations subjected to moving loads. First, based on the fundamental solutions of TI saturated media, the boundary element method (BEM) was adopted to derive the force-deformation equation of the soil-pile boundary. The finite element method (FEM) was then applied to establish the stiffness matrix equation of the Euler-based pile rows. Subsequently, by coupling the BEM and FEM equations, the screening efficiency of the pile rows was developed according to the barrier isolation theory. The proposed approach was validated using published numerical results. Finally, the effect of soil stratification on the screening effect of pile rows in TI saturated soils was investigated.
Application of material point method in modeling soil-geosynthetics interactions-a literature survey
Authors: Liu J , Lin C , Pokharel S
Published: May 2024

The material point method (MPM) has garnered significant attention in recent years owing to its advantages in solving soil–water-structure interaction problems involving large deformations in geotechnical engineering. The MPM combines the benefits of point-based and mesh-based approaches (finite element method) with both Eulerian computational mesh and continuum descriptions of materials. The successful integration of MPM in simulated landslides, internal erosion, and excavation has been frequently reported. However, solving the soil–geosynthetic interaction problem with the MPM has not been explored, although such problems often entail large deformations. The goal of this study is to collate studies on the simulation of geosynthetics and their interactions with soil using MPM. This paper first discusses the basics of MPM and the formation of thin membrane materials using MPM. It also includes limited applications of MPM in simulating soil–geosynthetic interactions. The applications demonstrate that the MPM is particularly effective in resolving large deformation problems associated with geosynthetics, including problems of landfill settlement, reinforced-slope stability, and geocontainer dropping.
Influences of number of geosynthetic reinforcement layers on soil arching under cyclic loading
Authors: Li G , Xu C , Zhou X , Shen P , Luo M
Published: May 2024

Geosynthetic-reinforced pile supported (GRPS) embankments have been widely used in highways and railways on soft subsoil. During the operation period, these embankments are often subjected to cyclic loading, such as traffic loading. Considering that soil arching is a key load transfer mechanism in these embankments, the development of soil arching under cyclic loading is vital important to operational safety of these embankments. Conventional trapdoor system cannot represent actual conditions of soil arching in GRPS embankments because it have a forcibly-moved trapdoor and cannot simulate load-induced subsoil settlement. Hence, this paper used a self-moving trapdoor supported by compression springs that moved up and down dependent on its overburden pressure. To investigate influences of number of geosynthetic reinforcement layers on soil arching under cyclic loading, two self-moving trapdoor tests were conducted, including a single layer and two layers, where the total reinforcement stiffness were approximately same. The trapdoor test results show that the inclusion of two reinforcement layers with a fill layer of a certain height in between reduced surface settlement of the fill and tensile forces of reinforcement, as compared with a single reinforcement layer. It also enhanced soil arching effect and improved the stability of soil arching under cyclic loading.
Predicting permeability coefficient in soil-rock mixtures using parameters from the negative exponential continuous grading equation
Authors: Chen Y H , Zhang L , Zhou J , Liu Z S
Published: May 2024

Soil-rock mixtures (SRMs) are widely utilized for embankment filling of highways in mountainous areas. The permeability characteristics of SRMs must be investigated as mountain highways are often exposed to strands of rainwater subjected to extreme rainfall. For the same species of SRM, its permeability is determined by its pore distribution and grading characteristics, which can be considered as an expression of particle grading and pore parameters. The predictive model of the SRMs permeability coefficient encompassing gradation coefficients and porosity was proposed based on the negative exponential continuous gradation equation and the Kozeny–Carman model. The applicability of the prediction model was verified based on the existing literature and performing SRMs seepage tests. The findings indicated that the permeability coefficient formula for SRMs established on the particle grading parameters and porosity was reasonable. Nevertheless, its current applicability is limited to the prediction of permeability coefficients for continuously graded SRMs. Consequently, further investigation is required to assess the suitability of the model for intermittently graded SRMs.
Centrifuge model tests on vertical stress distribution of geosynthetics reinforced soil (GRS) abutment
Authors: Wang Qingming , Xu Chao , Shen Panpan , Li Geye , Zhao Chongxi , Meng Ya
Published: May 2024

Geosynthetics reinforced soil (GRS) abutment has been widely used in the construction of small to medium single-span bridges and shows good service performance in engineering projects. Vertical stress distribution plays an important role for engineering design of the GRS abutments. Three centrifugal model tests of GRS abutments were carried out to investigate the vertical stress distribution underneath the centreline of beam seat, considering the setback distance (i.e., the distance from the beam seat to the inner of the facing) and beam seat width as influencing factors. Test results indicated the measured incremental vertical stresses under the beam seat increased with increasing loads uniformly and presented “larger on the upside and smaller on the downside” along the elevation. There existed the phenomenon of stress concentration near the top of the abutment and with the increasing beam seat width, the phenomenon of stress concentration presented more obvious. However, the setback distance had little effect on the vertical stress distribution. A comparison between measured and theoretical vertical stress showed that the AASHTO method provided a better prediction of the incremental vertical stress distribution than the FHWA method under the load of 200 kPa, but with the increasing loads, these two methods significantly underestimated the incremental vertical stress.
Experimental evaluation of one and two-directional wicking geotextile stabilized permeable base
Authors: Luo Leike , Guo Jun , Chen Aolong , Wen Wenhao
Published: May 2024

Incorporating wicking geotextiles significantly reduces the moisture levels in road bases under saturated and unsaturated conditions, improving the strength of granular materials and reducing water-related pavement damage. Despite the numerous well-documented applications of wicking geotextiles, most practical uses or research predominantly feature wicking fibers oriented in a single direction. Although theoretically incorporating multidirectional wicking fibers should enhance drainage efficiency, empirical studies on the impact of bidirectional fibers on geotextile drainage performance are scarce. A year-long comparative study was conducted in Shenzhen to examine the influence of fiber orientation. In this study, the moisture content in the aggregate base of a permeable sidewalk across three distinct test sections – single-directional, bidirectional, and no wicking geotextile – determined that two-directional wicking geotextiles are superior to their one-directional counterparts in reducing the volumetric water content in the granular base.
A rapid detection method for diesel content in diesel-contaminated soil based on dielectric measurement and oven-drying tests
Authors: Liu Zonghui , Lan Yinghao , Zhang Xiaolei , Zeng Fanzheng , Li Chuanghui
Published: May 2024

Geophysical testing techniques have been successfully applied to identify light non-aqueous phase liquids in soils, but challenges remain in rapidly detecting contaminant content. Detection of contaminants in soil using geophysical testing techniques relies on sensors sensitive to electrical and electromagnetic parameter changes. In this study, the complex permittivity of silty clay contaminated with 0# diesel was measured using an open-ended coaxial probe at frequencies from 200–3000 MHz, and the four-phase dielectric mixing models were evaluated. The measurement results showed that the complex refractive index method (CRIM) model provided a better match with the real permittivity of the four-phase system between 500–3000 MHz with relative errors within an acceptable range of 4%. To eliminate the unknown variable in the CRIM model, an improved equation for the relationship between water content and diesel content of the watery diesel-contaminated silty clay was established by the oven-drying method. Thus, a method for the rapid quantitative detection of the diesel content in contaminated soil has been developed based on dielectric measurement and oven-drying tests. The relative error between the calculated and actual set diesel content for ten manually configured diesel-contaminated soil samples was within 10%, with a maximum error of 15.75%.
An insight into laboratory column experiments for microplastic transport in soil
Authors: Gao Y , Sujathan S , El-Zein A
Published: May 2024

Plastic litter, most of which is landfilled or improperly disposed to aquatic and terrestrial environments, is a global environmental concern. Large-sized plastics can fragment into smaller pieces due to abrasion or weathering effects generating microplastics (MPs) which are tiny plastic debris smaller than 5 mm. In the aquatic environment, particularly oceans, MPs have been well documented in terms of their occurrence and toxicity. Soils have been shown to be an important sink of MPs, but the latter's fate and transport in the subsurface are not well understood. Laboratory studies have so far mostly employed rigid-wall columns to investigate MP transport through porous media, with a vast majority focusing on glass beads and predominantly sandy soils. Much less knowledge is available on MP transport in clay soils and minerals where transport mechanisms are much slower and the potential for chemical reactivity higher. There is hence a need for establishing experimental protocols for conducting such experiments. The paper presents preliminary results for an investigation assessing whether flexible wall permeameters (FWP) are suitable for the study of the transport of MPs in clayey soils. Key advantages of FWP are that they are widely available and commonly used and that they allow the control of effective stress in the sample. Two key questions addressed in this paper are whether the instruments themselves act as sink for MPs or as source of material that may interfere with the measurement of MPs in the effluent.
Influence of spatial variability in surrounding rock on fracture propagation in compressed air energy storage caverns
Authors: He X H , Zhou S W , Xu Y J , Qing S K
Published: May 2024

The expansion of fractures around underground caverns for compressed air energy storage (CAES) has a significant impact on engineering stability. We established a thermo-mechanical coupled random phase field model to investigate the trajectory of fractures in the heterogeneous surrounding rock of underground gas storage caverns. By simulating the different mechanical parameters under different coefficients of variation and autocorrelation distances, we explored the impact of spatial variability of rock mass on the fracture mode of surrounding rock in underground gas storage caverns. The results indicate that when only the spatial variability of elastic modulus is considered, the coefficient of variation primarily affects the inclination and curvature degree of fractures while the autocorrelation distance has a slight impact on the bending shape of fractures. When only the spatial variability of fracture energy release rate is considered, both the coefficient of variation and the autocorrelation distance have a negligible effect on fracture propagation. Compared with the elastic modulus of the rock mass, the fracture energy release rate has a more significant impact on the path of the cavern fractures.
Study on the mechanism of stone column pile formation
Authors: Cheng Z , Han S , Feng X , Zhang J , Wang F , Zhang D
Published: May 2024

This study focuses on the construction mechanism of stone column piles at an iron ore base in China. A theoretical model that describes the stone column pile formation process during sinking was proposed. The calculation formula for the air pressure required to open the pile tip valve during the pile formation process was derived according to the physical and mechanical parameters of the stratum, stone material parameters, and relevant dimensions of the pile tip valve. This ensured that the pile diameter satisfied the design requirements by successfully opening the pile tip valve. The required air pressure values for different pile lengths in the field were calculated based on this theoretical model, and they were found to be consistent with the actual field conditions. These results can serve as a reference for engineering projects.
Rigid inclusions performance as ground improvement for lacustrine clays
Authors: Colorado-Urrea G , Gonzalez Y D , Wang H , Zapata-Medina D , Carranza-Argote J
Published: May 2024

The Bogotá urban railway system involves constructing a rail maintenance yard covering 33 ha near the Bogotá River. It requires the construction of a 4.1 m embankment to overcome flood risks. Approximately 57,000 rigid inclusions (RI) were installed because of poor soil conditions to control excessive settlement. The embankment and RI were placed on a lacustrine deposit comprising layers with high organic matter content and soft clays that extended up to 200 m below ground surface. The effects of RI installation were reviewed using an inclinometer and benchmark data. Proof static load tests (SLT) and CPT were performed after RI installation to verify RI performance. CPTs were completed in the soil adjacent to the RI, as tested by the SLT. Different time spans were considered after RI installation for the CPT to assess the evolution of soil properties. The SLT uses the estimated working loads factored in by at least 20%. The CPT results showed that after a relatively short period of RI installation, the soil properties were similar to the initial properties. SLT results showed that RI capacity and head displacements were within the admissible ranges, considering that they had no competent bearing stratum, demonstrating the effectiveness of the ground improvement method. The results of both tests demonstrate the effectiveness of RI as a ground improvement technique for lacustrine soft clay in Bogotá.
Optimal screening method for dosage of calcium-based nanosilica modified expansive soils improver based on cost-effectiveness
Authors: Kang Bo , Zha Fusheng , Wang Jingwen , Pan Jun , Qin Lin
Published: May 2024

Under complex natural environments, the properties of lime-modified expansive soil may deteriorate. This facilitates the need for newer materials to develop composite modifiers to improve the anti-deterioration performance. Nanosilica (NS), which is a highly reactive material, is a good promoter of reaction systems with volcanic ash. In this paper, lime is mixed with NS according to a specified ratio to form calcium-based nanosilica (NS-C). NS-C significantly increased the unconfined compressive strength, cohesion, and internal friction angle and decreased the plasticity index, free swelling ratio, and permeability coefficient. The optimum ratio of nano-silica to lime in compound modifier was determined to be 1:8. NS can facilitate the production of a large amount of hydration products in the early stage of the reaction of stabilized soil, thus strengthening the connection between soil particles. In addition, NS exhibits good filling effect on the tiny pores between soil particles. The properties of NS-C stabilized soils with different ratios and curing times were determined to evaluate the modification effect and mechanism of composite modifier and obtain the optimal dosage for Hefei expansive soils in road-base edging technology. The optimum content of the compound modifier for expansive soils in the Hefei area should be 6 %, and the curing time should be at least 14 days.
Evaluation of earth retaining wall and adjacent underground structure behavior using 3D-FEM analysis
Authors: Kumagai Hiroto , Kono Takao , Nishiie Sho
Published: May 2024

Considering that excavation work in urban areas is often conducted close to the existing infrastructure, evaluating the impact of excavation on the surrounding area is crucial. Although step finite element method (FEM) analyses have been conducted to elucidate the behavior of the retaining wall and surrounding soil during excavation, evaluating the horizontal displacement of the retaining wall and the vertical displacement of the ground behind the retaining wall using linear elastic FEM analysis remains difficult. In this study, the behavior of the retaining wall and adjacent underground structure was evaluated by applying a three-dimensional elastoplastic step finite element method (FEM) analysis, in which the elastic modulus, considering the ground confining pressure and strain due to excavation, and the usefulness of setting the deformation coefficient were evaluated. The results indicated that the displacement behavior could be simulated using elastoplastic analysis, which sets the elastic modulus by considering the excavation effect for each region.
Analytical method for calculating internal forces and deformations in foundation pit support under asymmetric loading
Authors: Gu Kuanhai , Liu Fang
Published: May 2024

Sheet pile walls are significant forms of foundation pit supports that are widely employed in foundation pit support projects in combination with inner bracing. The complex geological conditions, surrounding environments, and earthwork excavations associated with foundation pits generally lead to noticeable asymmetric loading on a support system, posing challenges for accurately calculating the internal forces and deformations. To study the calculation methods for the internal forces and deformations in foundation pit support structures and bracing systems under asymmetric loading, a new model was established for foundation pits subjected to asymmetric unbalanced force loading on opposite sides. This method provides an adjusting technique for bracing forces on both sides based on the principle of equalizing axial forces, thereby providing a calculation approach for the stress and deformation of the foundation pit support system. Additionally, the developed axial force iterative calculation method was compared with numerical analysis methods to analyze the stress and deformation patterns in the support structure, which validated its effectiveness and accuracy.
Ultimate Lateral Resistance of Single Piles in Sand
Authors: Mu Linlong , Wang Shunwei , Huang Maosong
Published: May 2024

The p-y curve method is currently the most widely utilized analytical approach for horizontally loaded piles. Precisely determining the ultimate soil resistance is essential to enhance the accuracy of the p-y curve. Despite various scholars proposing methods to establish the law governing ultimate soil resistance with soil depth in the sand, significant discrepancies exist among these approaches. This paper posits that the three-dimensional failure mode of the shallow soil in front of the pile manifests as a cone when it reaches the limit state. The expression for the ultimate soil resistance of a single pile in shallow soil is derived through limit equilibrium theory, and subsequently, the modified p-y curve is obtained. The accuracy was validated through a comparison between the corrected p-y curve and results obtained from centrifugation experiments and field studies. In contrast to the API specification method, the refined hyperbolic function p-y curve demonstrates enhanced precision, facilitating precise predictions of pile head displacement and pile bending moments under horizontal loads.
Effect of sampling locations on reliability of pile groups
Authors: Zhang Yuting , Zou Di
Published: May 2024

Geotechnical site investigations represent an imperative prerequisite in the pursuit of reliable foundation designs. However, site investigations are frequently restricted to a limited number of locations owing to the constraints imposed by budget and time considerations, thereby potentially yielding a range of adverse consequences. Hence, the development of an efficient site investigation plan — one that optimally selects the number and location of tests, is important to gain adequate information for a given cost. This paper proposes a framework to identify optimal investigation locations by minimizing the probability of erroneous decisions (i.e., error types I and II). A pile group was adopted for the demonstration. The best locations corresponding to various numbers of tests were identified based on the derived probabilities of type I and II errors.
Improved CNN-based model for shape parameter determination of sand particles considering imbalanced dataset
Authors: Kim Donghwi , Youn Heejung
Published: May 2024

This study presents an artificial intelligence prediction model for determining the roundness and sphericity of sand particles using a convolutional neural network (CNN) regression model, which combines a CNN and a regression model. The dataset used for the model development consisted of 27,000 binary images of coarse grains with various shapes. To develop the prediction model, the validated algorithms, ResNet101 and ResNet152, were utilized and modified into a CNN regression model to predict the shape parameters. The performance of the developed model was evaluated using 3,000 randomly generated binary images, and the mean squared error and root mean squared error were calculated as evaluation metrics. The evaluation results indicated that the model effectively predicted the sphericity and roundness of sand particles, with a relatively low prediction performance observed for roundness.
Surrogate numerical prediction method of TBM position via FEM simulation and machine learning
Authors: Chang Jiaqi , Zhang Dongming , Huang Hongwei , Thewes Markus , Liu Xiaomin
Published: May 2024

The position of the tunnel boring machine (TBM) during tunnel construction is critical and must be precisely controlled. Owing to the geological uncertainty and complexity of the interaction between the ground and the TBM, controlling the position of the TBM is challenging. Hence, a surrogate numerical method is proposed to predict the position of the TBM using the finite element method (FEM) and machine learning method. First, a refined three-dimensional FEM model was established. Different values of the property parameters of the ground and the thrust force of the TBM were input into the FEM model, generating a database that includes 1000 cases. Subsequently, the database is used to train a gradient boosting regression (GBR) model. The GBR model learns from the database and establishes the relationship between the construction parameters, ground parameters, and TBM position as a surrogate model. The surrogate model exhibited high accuracy on the test set. With a geological survey and a construction parameter monitoring system, the TBM position could be predicted quickly and precisely using a surrogate model. The construction parameters were adjusted if the TBM position did not satisfy the requirements.
Composite evaluation method for route selection of linear underground space engineering based on numerical simulation and analytical hierarchy process
Authors: Xiaozhou Z
Published: May 2024

Currently, in the planning phase of linear underground space engineering, route selection evaluations rely mostly on qualitative methods or the quantitative Analytic Hierarchy Process (AHP). However, these evaluation methods often fail to adequately consider the specific effects of linear underground space engineering on the surface and surrounding structures during the planning phase. This study proposes a composite evaluation method based on numerical simulations and the AHP. For risk assessment, the AHP method was used to evaluate the risks of various indicators for linear underground engineering. In numerical simulations, automated modeling is employed to quantitatively analyze the effects of linear underground space engineering on geological strata and surrounding structures. The results of the AHP method and numerical simulation were combined as a composite evaluation method to analyze route selection in linear underground space engineering. Finally, this method is demonstrated through a case study of a proposed rail transit project on the Yuzhong Peninsula, Chongqing.
Impact of climate change on underground transport infrastructure
Authors: Porro R P , O´Donovan J , Li Z
Published: May 2024

Globally, underground transport infrastructures in many countries face significant challenges owing to extreme weather events, such as heavy rainfall, extreme temperature changes, and rising sea levels. Consequently, it is critical to perform a comprehensive examination of the diverse effects of these climatic phenomena on underground transport infrastructures and their ability to mitigate such consequences. This study focuses on assessing the impact of climate change on underground transport infrastructures using innovative monitoring tools. Wireless sensor networks (WSNs) and do it yourself (DIY) drones will be deployed to monitor these assets to detect potential problems at an early stage. This approach involves collecting real-time data through WSNs and capturing high-quality images using drone flights. The objective is to achieve an efficient response to extreme weather events and to enhance our understanding of the impact of climate change on underground transport infrastructures.
Research on intelligent identification and resource utilization of TBM muck in breezy granite strata
Authors: You Yuyang , Yang Junsheng , Tang Yu , Yang Xifeng
Published: May 2024

Tunnel boring machines (TBMs) excavating breezed granite strata produce a lot of muck, including rock powder and gravel. To promote waste recycling and environmentally friendly muck utilization, a series of studies was conducted on the intercity railway section from ShenZhen Airport East Station to HuangMaBu Station in China. First, the muck image dataset was obtained using a camera, and the SAM-YOLO neural network model was adopted to intelligently identify the features of the particle size and content of the muck. Subsequently, the muck was used as an alternative material for the backfill slurry raw material, and the optimal slurry ratio was determined through laboratory tests. Finally, a new backfill slurry was applied on-site. The results demonstrated that the established SAM-YOLO model can accurately and quickly identify muck characteristics, which can be roughly classified by particle size into three categories: rock powder (0-5 mm), gravel (5-10 mm), and crushed rock (10-31.5 mm). Rock powder was utilized to make the monomortar, gravel was used for backfilling, and the crushed rock was broken again to gravel particle size to be used for backfilling. The laboratory test and field application results indicated that the new monomortar can fulfil engineering requirements after the backfilling of gravel, and the optimal water, cement, and rock powder mix ratio is 0.9:1.0:1.0. This research thus provides effective guidance for the utilization of muck in similar projects.
Application of plastic concrete interlocking piles for slope seepage prevention in riprap foundation retaining engineering
Authors: Huang X , Li Z , Li D , Zhen X
Published: May 2024

Based on the foundation pit support project at Shenzhen Shekou cruise center, the application of plastic concrete interlocking piles in slope seepage prevention in a riprap foundation support project near the sea was investigated via finite element analysis. From the characteristics of plastic concrete pile, the modulus of the same, elastic modulus of surrounding riprap foundation, diameter of pile, water level and other factors for slope stability, and influence of plastic concrete pile on slope stability and deformation was obtained. Based on the analysis, key suggestions on the anti-seepage characteristics of plastic concrete pile in slopes were made, and the anti-seepage application of plastic concrete pile in reclamation foundations in airports and power plants were prospected.
Numerical investigation of spudcan penetration in sand with interbedded clay
Authors: Li Tingting , Li Sa , Dai Jialin , Luo Lunbo , Zhai Hanbo
Published: May 2024

Jack-up units are extensively utilized in offshore geotechnical investigations and the recent installation of wind turbine foundations. Engineers require accurate predictions of spudcan penetration resistance to assess its final penetration depth and identify potential risks, e.g., punch-through, ensuring safety during the installation of jack-up units. Notably, for seabed stratigraphy comprising sand with interbedded clay layers, a significant discrepancy exists between the penetration resistance calculated using current industry guidelines and actual measured results. In this study, three-dimensional (3D) large deformation finite-element (LDFE) analyses were performed to model the spudcan penetration response in a seabed consisting of a sand–clay–sand soil profile. A comprehensive parametric study was conducted to examine the influence of soil strength and layer thickness on penetration resistance. The variations of the soil failure mechanisms are demonstrated and associated with the varying penetration resistance, which form the basis of the new calculation method developed for the sand seabed with interbedded clay.
Study on preparation and properties of polyurethane modified epoxy resin lotion cementing slurry
Authors: Mao Chaojing
Published: May 2024

To solve the problems of poor cementing quality and weak consolidation performance of deep-water shallow cementing cement, a low-temperature curable polyurethane-modified epoxy resin lotion (WER) was prepared with epoxy resin and polyurethane as raw materials, and its hydrophilic groups (carboxyl and ether bonds) were self emulsified. The results show that the modified WER lotion cement slurry has good fluidity and stability. Its thickening transition time is less than 16 min, which can effectively prevent gas channeling. In addition, its low-temperature mechanical properties have been significantly improved, and its compressive strength has increased by 42.4% and 44.5% compared to net slurry cement within 3 and 7 days, while its elastic modulus has decreased by 34.1% and 42.4%, respectively.
Effectiveness of dance interventions for falls prevention in older adults: systematic review and meta-analysis
Authors: Lazo Green Kimberly , Yang Yang , Abaraogu Ukachukwu , Eastaugh Claire H , Beyer Fiona R , Norman Gill , Todd Chris
Published: May 2024

Introduction

Fall prevention is a global health priority. Strength and balance exercise programmes are effective at reducing falls. Emerging literature suggests dance is an enjoyable and sociable form of exercise. However, there is little evidence that dance reduces fall incidence.

Methods

Systematic review and meta-analysis examining effectiveness and cost-effectiveness of dance for falls prevention in older adults. Five databases were searched with no restrictions on publication date or intervention settings. Risk of bias was assessed using variants of Cochrane Risk of bias tools, Mixed-Methods Appraisal and Drummond checklist as appropriate. Certainty of evidence was assessed using GRADE.

Results

Forty-one studies were included (19 RCTs, 13 quasi-experimental, two mixed-method, seven observational studies, 2,451 participants). Five types of dance interventions were identified: ballroom and Latin dance, dance exercise, cultural dance, dance therapy, and low-impact dance. Meta-analysis was only possible for functional outcome measures: Timed-Up-and-Go (dance versus usual care, mean difference (MD) = 1.36; 95% CI −3.57 to 0.85), Sit-to-Stand (dance versus exercise MD = −0.85; 95% CI −2.64 to 0.93: dance versus education MD = −1.64; 95% CI −4.12 to 0.85), Berg Balance Scale (dance versus usual care MD = 0.61; 95% CI −4.26 to 5.47). There was unexplained variance in effects and no significant differences between intervention and control groups. Overall, certainty of evidence was very low; we are uncertain about the effect of dance interventions in reducing falls.

Conclusions

There is very low certainty evidence for dance as an alternative to strength and balance training if the aim is to prevent falls. No robust evidence on the cost-effectiveness of dance interventions for the prevention of falls was found.

PROSPERO registration

CRD42022382908.
Age-associated changes in multimodal pain perception
Authors: Zhi Yongkang , Zhang Yu , Zhang Yu , Zhang Ming , Kong Yazhuo
Published: May 2024

Background

Pain sensitivity varies across multimodal somatosensory stimuli that can rely on different conductive fibres, which, when damaged, will lead to neuropathies. However, there is limited research examining the characteristics of perceived pain, particularly as affected by the ageing process, as induced by various somatosensory stimuli that may rely on small or large fibres.

Methods

Using heat and pressure stimuli on small and large fibres separately on both younger and older adults, this study examined age-associated changes in pain perception by measuring self-reported pain sensitivity, pain threshold and pain discriminability.

Results

Heat pain threshold was significantly positively correlated with age, but not pressure pain threshold. Pain threshold increased and pain discriminability decreased in response to heat stimuli in the older participants compared with the younger ones.

Conclusion

An age-associated decline in heat pain perception was observed, suggesting an earlier degradation of heat perception. These findings provide new insight into understanding and assessing somatosensory disorders, which can help ageing populations better maintain healthy sensory functioning.
The role and limitations of electronic medical records versus patient interviews for determining symptoms of, underlying comorbidities of, and medication use by patients with COVID-19
Authors: Soto Raymond A , Vahey Grace M , Marshall Kristen E , McDonald Emily , Herlihy Rachel , Chun Helen M , Killerby Marie E , Kawasaki Breanna , Midgley Claire M , Alden Nisha B , Tate Jacqueline E , Staples J Erin , Team Colorado Investigation
Published: May 2024

Electronic medical records (EMRs) are important for rapidly compiling information to determine disease characteristics (eg, symptoms) and risk factors (eg, underlying comorbidities, medications) for disease-related outcomes. To assess EMR data accuracy, agreement between EMR abstractions and patient interviews was evaluated. Symptoms, medical history, and medication use among patients with COVID-19 collected from EMRs and patient interviews were compared using overall agreement (ie, same answer in EMR and interview), reported agreement (yes answer in both EMR and interview among those who reported yes in either), and κ statistics. Overall, patients reported more symptoms in interviews than in EMR abstractions. Overall agreement was high (≥50% for 20 of 23 symptoms), but only subjective fever and dyspnea had reported agreement of ≥50%. The κ statistics for symptoms were generally low. Reported medical conditions had greater agreement with all condition categories (n = 10 of 10) having ≥50% overall agreement and half (n = 5 of 10) having ≥50% reported agreement. More nonprescription medications were reported in interviews than in EMR abstractions, leading to low reported agreement (28%). Discordance was observed for symptoms, medical history, and medication use between EMR abstractions and patient interviews. Investigations using EMRs to describe clinical characteristics and identify risk factors should consider the potential for incomplete data, particularly for symptoms and medications.
Volumetric apparent diffusion coefficient histogram analysis in term neonatal asphyxia treated with hypothermia
Authors: Seber Turgut , Uylar Seber Tuğba , Özdemir Ahmet , Baştuğ Osman , Keskin Şuayip , Aktaş Elif
Published: May 2024

Objectives

Our aim is to estimate the long-term neurological sequelae and prognosis in term neonatal asphyxia treated with hypothermia via volumetric apparent diffusion coefficient (ADC) map histogram analysis (HA).

Methods

Brain MRI studies of 83 term neonates with asphyxia who received whole-body hypothermia treatment and examined between postnatal (PN) fourth and sixth days were retrospectively re-evaluated by 2 radiologists. Volumetric HA was performed for the areas frequently affected in deep and superficial asphyxia (thalamus, lentiform nucleus, posterior limb of internal capsule, corpus callosum forceps major, and perirolandic cortex-subcortical white matter) on ADC map. The quantitative ADC values were obtained separately for each region. Qualitative-visual (conventional) MRI findings were also re-evaluated. Neonates were examined neurodevelopmentally according to the Revised Brunet-Lezine scale. The distinguishability of long-term neurodevelopmental outcomes was statistically investigated.

Results

With HA, the adverse neurodevelopmental outcomes could only be distinguished from mild-moderated impairment and normal development at the thalamus with 10th percentile ADC (P = .02 and P = .03, respectively) and ADCmin (P = .03 and P = .04, respectively). Also with the conventional MRI findings, adverse outcome could be distinguished from mild-moderated impairment (P = .04) and normal development (P = .04) via cytotoxic oedema of the thalamus, corpus striatum, and diffuse cerebral cortical.

Conclusion

The long-term adverse neurodevelopmental outcomes in newborns with asphyxia who received whole-body hypothermia treatment can be estimated similarly with volumetric ADC-HA and the conventional assessment of the ADC map.

Advances in knowledge

This study compares early MRI ADC-HA with neurological sequelae in term newborns with asphyxia who received whole-body hypothermia treatment. We could not find any significant difference in predicting adverse neurological sequelae between the visual-qualitative evaluation of the ADC map and HA.