Distribution and Susceptibility Assessment of Collapses and Landslides in the Riparian Zone of the Xiaowan Reservoir

The southwest alpine gorge region is the major state base of hydropower energy development in China and hence planned many cascading hydropower stations. After the reservoir impoundment, the intense water level fluctuations under the interaction of cascade dams operating and the mountainous flooding, usually cause bank collapse, landslide and debris flow hazards. The Xiaowan reservoir(XWR), for example, as the ‘dragon head' meg reservoir located in the middle mainstream of Lancang River, have resulted in a series of geohazards during its building and operating. In this study, we investigated the number and surface area of collapses and landslides(CLs) occurred in the water level fluctuations zone(WLFZ) of XWR using remote sensing images of Gaofen-1 and Google Earth; evaluated the CLs susceptibility using information value method. The results presented that the total WLFZ area of 87.03 km2 and 804 CLs masses with a total area of 1.98 km2 were identified in the riparian zone of XWR. CLs mainly occurred at an elevation of 1190–1240 m, and the CLs density increased with an increase in altitude. The WLFZ with a slope gradient of 25°– 45° is the main CLs distribution area that accounts for more than half of the total CLs area. The susceptibility assessment revealed that high and very high susceptibility zones are generally distributed along zones with an elevation of 1210–1240 m, a slope degree of 25°–45° and a slope aspect perpendicular to the direction of Lancang River. Furthermore, these susceptible zones are close in distance to the dam site and tend to be in the riparian zones with the formation lithology of Silurian strata. These results provide a valuable contribution to prevent and control geohazards in the XWR area. Moreover, this study offers a constructive sample of geohazards assessment in the riparian zone of large reservoirs throughout the mountains of southwest China.

Numerical analysis of downward progressive landslides in long natural slopes with sensitive clay

Landslides occurring in sensitive clay often result in widespread destruction,posing a significant risk to human lives and property due to the substantial decrease in undrained shear strength during deformation.Assessing the consequences of these landslides is challenging and necessitates robust numerical methods to comprehensively investigate their failure mechanisms.While studies have extensively explored upward progressive landslides in sensitive clays,understanding downward progressive cases remains limited.In this study,we utilised the nodal integration-based particle finite element method(NPFEM)with a nonlinear strain-softening model to analyse downward progressive landslides in sensitive clay on elongated slopes,induced by surcharge loads near the crest.We focused on elucidating the underlying failure mechanisms and evaluating the effects of different soil parameters and strainsoftening characteristics.The simulation results revealed the typical pattern for downward landslides,which typically start with a localised failure in proximity to the surcharge loads,followed by a combination of different types of failure mechanisms,including single flow slides,translational progressive landslides,progressive flow slides,and spread failures.Additionally,inclined shear bands occur within spread failures,often adopting distinctive ploughing patterns characterised by triangular shapes.The sensitive clay thickness at the base,the clay strength gradient,the sensitivity,and the softening rate significantly influence the failure mechanisms and the extent of diffused displacement.Remarkably,some of these effects mirror those observed in upward progressive landslides,underscoring the interconnectedness of these phenomena.This study contributes valuable insights into the complex dynamics of sensitive clay landslides,shedding light on the intricate interplay of factors governing their behaviour and progression.

Predicting impact forces on pipelines from deep-sea fluidized slides:A comprehensive review of key factors

Deep-sea pipelines play a pivotal role in seabed mineral resource development,global energy and resource supply provision,network communication,and environmental protection.However,the placement of these pipelines on the seabed surface exposes them to potential risks arising from the complex deep-sea hydrodynamic and geological environment,particularly submarine slides.Historical incidents have highlighted the substantial damage to pipelines due to slides.Specifically,deep-sea fluidized slides(in a debris/mud flow or turbidity current physical state),characterized by high speed,pose a significant threat.Accurately assessing the impact forces exerted on pipelines by fluidized submarine slides is crucial for ensuring pipeline safety.This study aimed to provide a comprehensive overview of recent advancements in understanding pipeline impact forces caused by fluidized deep-sea slides,thereby identifying key factors and corresponding mechanisms that influence pipeline impact forces.These factors include the velocity,density,and shear behavior of deep-sea fluidized slides,as well as the geometry,stiffness,self-weight,and mechanical model of pipelines.Additionally,the interface contact conditions and spatial relations were examined within the context of deep-sea slides and their interactions with pipelines.Building upon a thorough review of these achievements,future directions were proposed for assessing and characterizing the key factors affecting slide impact loading on pipelines.A comprehensive understanding of these results is essential for the sustainable development of deep-sea pipeline projects associated with seabed resource development and the implementation of disaster prevention measures.

Airblast evolution initiated by Wangjiayan landslides in the M_(s)8.0 Wenchuan earthquake and its destructive capacity analysis

Airblasts,as one common phenomenon accompanied by rapid movements of landslides or rock/snow avalanches,commonly result in catastrophic damages and are attracting more and more scientific attention.To quantitatively analyze the intensity of airblast initiated by landslides,the Wangjiayan landslide,occurred in the Wenchuan earthquake,is selected here with the landslide propagation and airblast evolution being studied using FLUENT by introducing the Voellmy rheological law.The results reveal that:(1)For the Wangjiayan landslide,its whole travelling duration is only 12 s with its maximum velocity reaching 36 m/s at t=10 s;(2)corresponding to the landslide propagation,the maximum velocity,28 m/s,of the airblast initiated by the landslide also appears at t=10 s with its maximum pressure reaching594.8 Pa,which is equivalent to violent storm;(3)under the attack of airblast,the load suffered by buildings in the airblast zone increases to 1300 Pa at t=9.4 s and sharply decreased to-7000 Pa as the rapid decrease of the velocity of the sliding mass at t=10 s,which is seriously unfavorable for buildings and might be the key reason for the destructive collapse of buildings in the airblast zone of the Wangjiayan landslide.

基于Slide的研山铁矿高陡边坡稳定性分析

露天矿山边坡稳定性对采场安全生产至关重要。为探究边坡施工过程中的安全隐患,以研山铁矿高陡边坡为研究对象,考虑爆破震动及地震作用荷载,运用Slide二维边坡数值模拟软件对典型剖面进行稳定性计算。结果表明:在正常工况条件、爆破震动及地震作用下,边坡整体安全系数符合要求,整体处于稳定状态。但在爆破震动及地震作用下,边坡局部安全系数介于临界值,可能存在局部滑坡风险。为保证采场生产安全,提出了相应的边坡管理预防措施,为相关实践工作提供一定参考。

CrossLinkNet: An Explainable and Trustworthy AI Framework for Whole-Slide Images Segmentation

In the intelligent medical diagnosis area,Artificial Intelligence(AI)’s trustworthiness,reliability,and interpretability are critical,especially in cancer diagnosis.Traditional neural networks,while excellent at processing natural images,often lack interpretability and adaptability when processing high-resolution digital pathological images.This limitation is particularly evident in pathological diagnosis,which is the gold standard of cancer diagnosis and relies on a pathologist’s careful examination and analysis of digital pathological slides to identify the features and progression of the disease.Therefore,the integration of interpretable AI into smart medical diagnosis is not only an inevitable technological trend but also a key to improving diagnostic accuracy and reliability.In this paper,we introduce an innovative Multi-Scale Multi-Branch Feature Encoder(MSBE)and present the design of the CrossLinkNet Framework.The MSBE enhances the network’s capability for feature extraction by allowing the adjustment of hyperparameters to configure the number of branches and modules.The CrossLinkNet Framework,serving as a versatile image segmentation network architecture,employs cross-layer encoder-decoder connections for multi-level feature fusion,thereby enhancing feature integration and segmentation accuracy.Comprehensive quantitative and qualitative experiments on two datasets demonstrate that CrossLinkNet,equipped with the MSBE encoder,not only achieves accurate segmentation results but is also adaptable to various tumor segmentation tasks and scenarios by replacing different feature encoders.Crucially,CrossLinkNet emphasizes the interpretability of the AI model,a crucial aspect for medical professionals,providing an in-depth understanding of the model’s decisions and thereby enhancing trust and reliability in AI-assisted diagnostics.

Early Devonian Post-collisional Granitic Magmatism in the North Qilian Orogenic Belt,Western China:Insights into Lithospheric Delamination and Orogenic Collapse

Post-collisional magmatism contains important clues for understanding the reworking and growth of continental crust,as well as lithospheric delamination and orogenic collapse.Early Devonian magmatism has been identified in the North Qilian Orogenic Belt(NQOB).This paper reports an integrated study of petrology,whole-rock geochemistry,Sm-Nd isotope and zircon U-Pb dating,as well as Lu-Hf isotopic data,for two Early Devonian intrusive plutons.The Yongchang and Chijin granites yield zircon U-Pb ages of 394-407 Ma and 414 Ma,respectively.Both of them are characterized by weakly peraluminous to metaluminous without typical aluminium-rich minerals,LREE-enriched patterns with negative Eu anomalies and a negative correlation between P_(2)O_(5) and SiO_(2) contents,consistent with geochemical features of I-type granitoids.Zircons from the studied granites display negative to weak positive ε_(Hf)(t)values(−5.7 to 2.1),which agree well with those of negative ε_(Nd)(t)values(−6.4 to−2.9)for the whole-rock samples,indicating that they were derived from the partial melting of Mesoproterozoic crust.Furthermore,low Sr/Y ratios(1.13-21.28)and high zircon saturation temperatures(745℃ to 839℃,with the majority being>800℃)demonstrated a relatively shallow depth level below the garnet stability field and an additional heat source.Taken together,the Early Devonian granitic magmatism could have been produced by the partial melting of ancient crustal materials heated by mantle-derived magmas at high-temperature and low-pressure conditions during postcollisional extensional collapse.The data obtained in this study,when viewed in conjunction with previous studies,provides more information about the tectonic processes that followed the closure of the North Qilian Ocean.The tectonic transition from continental collision to post-collisional delamination could be constrained to~430 Ma,which is provided by the sudden decrease of Sr/Y and La/Yb ratios and an increase in zircon ε_(Hf)(t)values for granitoids.A two-stage tectonic evolution model from continental collision to post-collisional extensional collapse for the NQOB includes(a)continental collision and crustal thickening during ca.455-430 Ma,characterized by granulite-facies metamorphism and widespread low-Mg adakitic magmatism;(b)post-collisional delamination of thickened continental crust and extensional collapse of orogen during ca.430-390 Ma,provided by coeval high-Mg adakitic magmatism,A-type granites and I-type granitoids with low Sr-Y ratios.

Roof collapse mechanism of weak surrounding rock for deep-buried tunnels under high geostress conditions

High geostress,a typical attribute of tunnels located at significant depths,is crucial in causing stress-induced failure and influencing the stability of the tunnel crown.This study developed an analytical method for the failure mechanism that occurs in deep-buried tunnel roofs,taking into account the influence of geostress.The limit analysis theory was utilized for deriving analytical solutions about the geometry of the collapsing surface and the limit supporting pressure.The collapsing surface obtained by the analytical solution was validated by the findings of the physical model test,which shows a high level of agreement with the actual one.An extensive investigation was done to explore the effects of the lateral pressure coefficients,the tunnel buried depth,the geological conditions of the surrounding rock,the long-short axis ratio,and the size of the tunnel profile.The findings indicate that an increase in the lateral pressure coefficient from 0.5 to 1.5 results in a reduction in the height of the collapsing zone by 2.08 m and the width of the collapsing zone by 1.15 m,while simultaneously increases the limit supporting pressure by 18.9%.The proposed upper bound method accurately determines the limit supporting pressure and the geometry of the collapsing surface,which aligns well with the results acquired through numerical modelling and on-site monitoring in actual engineering applications.The proposed analytical method can serve as a reference for similar crown failure issues of deep-buried tunnels.

基于SLIDE软件的某矿山排土场稳定性分析

为研究某矿山排土场稳定性,使用SLIDE软件,采用简化Bishop法、Janbu修正法和Spencer法对该排土场自然工况、降雨工况和地震工况下的安全系数进行计算。结果表明,该排土场边坡在自然和降雨工况下处于稳定,在地震工况下处于基本稳定,由此为该排土场将来的维护和治理作业提供了参考价值。

Collapse Behavior of Pipe-Framed Greenhouses with and without Reinforcement under Snow Loading:A 3-D Finite Element Analysis

The present paper first investigates the collapse behavior of a conventional pipe-framed greenhouse under snow loading based on a 3-D finite element analysis,in which both geometrical and material non-linearities are considered.Three snow load distribution patterns related to the wind-driven snow particle movement are used in the analysis.It is found that snow load distribution affects the deformation and collapse behavior of the pipe-framed greenhouse significantly.The results obtained in this study are consistent with the actual damage observed.Next,discussion is made of the effects of reinforcements by adding members to the basic frame on the strength of the whole structure,in which seven kinds of reinforcement methods are examined.A buckling analysis is also carried out.The results indicate that the most effective reinforcement method depends on the snow load distribution pattern.

Progressive Collapse Resistance of a New Staggered Story Isolated System

A new staggered isolated system developed from the mid-story isolated system is the new staggered story isolated system. There are not many studies on this structure currently. In this study, an 18-story new staggered story isolated system model is established using SAP2000. The dynamic nonlinear dynamic alternate method is used to analyze the structure against progressive collapse. Results show that the structure has good resistance to progressive collapse, and there is no progressive collapse under each working condition. The progressive collapse does not occur for the case of removing only one vertical structural member of the new staggered of isolated system. The side column has big influence on this isolated structures’ progressive collapse;the removal of vertical structural member of the isolation layer has less impact on the structure than the removal of the bottom vertical structural member. After the removing of the member, the internal force of the structure will be redistributed, and the axial force of the adjacent columns will change obviously, showing a trend of “near large and far small”.

基于Slide2的某铁矿尾矿库坝体稳定性分析

尾矿库是冶金矿山的重要附属设施,一旦失事将造成严重的环境污染和重大损失,尾矿库安全的核心在于尾矿坝是否稳定。通过采用Slide2软件,根据岩土工程勘察资料,建立山西某铁矿尾矿库坝体典型剖面的二维数值模型,对坝体三种运行工况下的渗流稳定性和坝坡稳定性进行分析,以确定尾矿库的安全性,并分析Slide2软件应用于尾矿坝稳定性分析中的可靠性和功能性。

支气管镜在儿童Slide气管成形术中的应用

目的 总结支气管镜在儿童Slide气管成形术中的作用。方法 回顾性分析2017—2020年湖南省人民医院收治的4例气管狭窄患儿的诊疗经过,总结支气管镜在Slide气管成形术术前评估、术中定位与测量及术后创面评估和治疗中的作用。结果 Slide气管成形术术前支气管镜评估显示,4例患儿中3例存在完全气管环,2例合并肺动脉吊带,2例存在多处狭窄。3例在该院完成Slide气管成形术,术中支气管镜下判断狭窄段中点及测量狭窄段长度,协助离断气管狭窄段,术后灌洗明确病原;1例外院Slide气管成形术术后9个月出现瘢痕牵拉,经支气管镜下介入治疗好转。2例术后第4天支气管镜下发现气管黏膜改变,调整治疗方案;2例术后1个月出现肉芽增生,经支气管镜下冷冻治疗好转。1例因吻合口坏死放弃治疗死亡,存活的3例随访6个月以上,预后可,但均存在气管支气管软化。结论 支气管镜可用于气管狭窄患儿Slide气管成形术的管理,有助于术后康复及随访。

HL-2A托卡马克上slide-away放电特征研究

托卡马克装置上等离子体不稳定性会被非麦克斯韦分布的逃逸电子激发。逃逸电子在特定条件下会与不稳定性发生反常多普勒共振,此共振结果将降低逃逸电子的能量,减小对装置造成的危害。本文利用电子回旋辐射(ECE)等诊断系统分析了HL-2A上slide-away放电中反常多普勒共振特征。实验结果表明:slide-away放电模式下ECE信号主要有台阶型、指数型、指数-台阶型和双波型4类波形。统计显示不稳定性阈值与等离子体电流以及磁场强度值无线性关系。反常多普勒不稳定性阈值(ωpe/ωce)统计分布范围约为0.17~0.80,其中最高值分布范围为0.35~0.40。

基于Slide的水电站高边坡稳定性分析及支护方案研究

基于Slide软件,采用极限平衡法计算某水电站边坡在正常运行及降雨工况下的稳定性,同时研究了回填石渣和增设土钉处理2种支护方案的实施效果。结果表明,该处边坡在正常运用及降雨工况的安全系数均小于规范要求的下限值,不满足规范要求,需采取一定措施进行支护。为增加边坡的稳定性,采用回填石渣和增设土钉处理2种支护方案,加固后的边坡的稳定性均满足规范要求。

过去十年美国学校图书馆员情况研究——基于SLIDE项目报告的分析

基于网络调查法和内容分析法,论文通过分析SLIDE项目发布的报告,确定过去十年美国学校图书馆员的情况,即馆员建设专业化与职业化水平比较高,全国馆员人数大幅减少,馆员数量不能满足教与学需求,馆员数量在各州层面和各学区层面配置不均衡,希望美国的经验和教训能为我国中小学图书馆员队伍建设和人才培养提供借鉴。

A failure criterion for shale considering the anisotropy and hydration based on the shear slide failure model

A failure criterion fully considering the anisotropy and hydration of shale is essential for shale formation stability evaluation.Thus,a novel failure criterion for hydration shale is developed by using Jaeger’s shear failure criterion to describe the anisotropy and using the shear strength reduction caused by clay minerals hydration to evaluate the hydration.This failure criterion is defined with four parameters in Jaeger’s shear failure criterion(S_(1),S_(2),a andφ),three hydration parameters(k,ω_(sh)andσ_(s))and two material size parameters(d and l0).The physical meanings and determining procedures of these parameters are described.The accuracy and applicability of this failure criterion are examined using the published experimental data,showing a cohesive agreement between the predicted values and the testing results,R^(2)=0.916 and AAREP(average absolute relative error percentage)of 9.260%.The error(|D_(p)|)is then discussed considering the effects ofβ(angle between bedding plane versus axial loading),moisture content and confining pressure,presenting that|Dp|increases whenβis closer to 30°,and|D_(p)|decreases with decreasing moisture content and with increasing confining pressure.Moreover,|D_(p)|is demonstrated as being sensitive to S1and being steady with decrease in the data set whenβis 0°,30°,45°and 90°.

2例肺动脉气管换位联合Slide重建术患儿的术后护理

目的探讨肺动脉气管换位联合Slide重建术患儿的术后护理要点。方法总结2020—2021年浙江大学医学院附属儿童医院收治2例肺动脉吊带合并气管支气管狭窄行肺动脉气管换位联合Slide重建术患儿的术后护理,对2例患儿进行多项针对性护理措施以预防并发症的发生,通过纤维支气管镜检查,及时发现气道并发症;术后密切观察有无气管吻合口瘘;做好呼吸道管理,预防呼吸道阻塞;加强术后营养支持,促进患儿术后康复。结果经过精心治疗和护理,2例患儿恢复良好,分别于入院第64天和第28天康复出院。随访1~6个月,通过复查心脏B超和纤维支气管镜检查,患儿未见明显异常。结论肺动脉气管换位联合Slide重建术后密切关注患儿的吻合口和呼吸道是护理重点,饮食护理在康复过程中起到重要作用。

基于SLIDE软件矿山边坡稳定性分析的研究

本文通过介绍对绍兴县毛婆溪石材矿现状边坡的稳定性研究的内容,揭示中仿Slide 6.0边坡分析软件在矿山边坡分析中的应用方法。中仿Slide 6.0边坡分析软件能直接显示边坡安全系数的计算结果,但在不同的工况下或者使用不同的分析方法会得到不同的计算结果。本文所使用的方法对其他同类矿山具有一定参考意义。

基于Slide法的磨坊露天磷矿边坡稳定性分析

针对磨矿露天磷矿特有的工程地质特征,选取了2个典型的最危险盘边坡剖面,运用Slide边坡分析软件进行稳定性计算分析。计算结果表明:设计的边坡稳定性良好,安全系数满足安全系数限制的要求。该结果验证了施工图阶段所设计的边坡参数能够满足现场实际的技术标准和生产需要,该结论对磨坊露天磷矿安全生产作业具有重大的指导作用。