Consolidation of high replacement ratio stone column-reinforced ground:Analytical solutions incorporating clogging effect

The utilization of stone columns has emerged as a popular ground improvement strategy,whereas the drainage performance can be adversely hampered by clogging effect.Despite the ample progress of calculation methods for the consolidation of stone column-improved ground,theoretical investigations into the clogging effect have not been thoroughly explored.Furthermore,it is imperative to involve the column consolidation deformation to mitigate computational error on the consolidation of composite ground with high replacement ratios.In this context,an analytical model accounting for the initial clogging and coupled time and depth-dependent clogging of stone columns is established.Then,the resulting governing equations and analytical solutions are obtained under a new flow continuity relationship to incorporate column consolidation deformation.The accuracy and reliability of the proposed model are illustrated by degradation analysis and case studies with good agreements.Subsequently,the computed results of the current study are juxtaposed against the existing models,and an in-depth assessment of the impacts of several crucial parameters on the consolidation behavior is conducted.The results reveal that ignoring column consolidation deformation leads to an overestimate of the consolidation rate,with maximum error reaching up to 16%as the replacement ratio increases.Furthermore,the initial clogging also has a significant influence on the consolidation performance.Additionally,the increment of depth and time-clogging factors a and b will induce a noticeable retardation of the consolidation process,particularly in the later stage.

Shape Analysis of Agricultural Parcels for Land Consolidation Priorities in Tekirdag Province,Turkey

Shape irregularity,a sub-factor of parcel fragmentation is a problem that hinders sustainable agriculture and is solved using land consolidation projects.Determination of the parcel shape degree contributes significantly to spatial prioritization where there is also a high probability of achieving positive effects of consolidation projects.This study aims to determine the shape degree of the agricultural parcels both at singular and rural county scales in Tekirdag Province,Turkey in 2020 by combining the parcel shape index(PSI) with the minimum bounding geometry index(MBG) to improve parcel scores.Hot-spot zones of the highly irregular and near optimum parcels were also determined using Getis-Ord G_(i)^(*) statistic.The parcel degrees were classified into four categories,namely highly irregular,irregular,regular and near optimum.The obtained unweighted scores of the parameters exhibit deviations from the expected values.After weighting by pairwise comparison,the values approached ideal scores.Among 346 740 parcels,53% were highly irregular and irregular and 47% were regular and near optimum shapes after weighting whereas these were 70% and 30%,respectively before weighting.The average parcel degree of 63 rural counties was regular while the average parcel degree of the remaining 264 rural counties was irregular.The combined use of PSI and MBG index improved the correctness of the parcel shape score.It could be suggested to use as a tool in land consolidation prioritization.

Effect of particle composition and consolidation degree on the wave-induced liquefaction of soil beds

The wave-induced liquefaction of seabed is responsible for causing damage to marine structures.Particle composition and consolidation degree are the key factors affecting the pore water pressure response and liquefaction behavior of the seabed under wave action.The present study conducted wave flume experiments on silt and silty fine sand beds with varying particle compositions.Furthermore,a comprehensive analysis of the differences and underlying reasons for liquefaction behavior in two different types of soil was conducted from both macroscopic and microscopic perspectives.The experimental results indicate that the silt bed necessitates a lower wave load intensity to attain the liquefaction state in comparison to the silty fine sand bed.Additionally,the duration and development depth of liquefaction are greater in the silt bed.The dissimilarity in liquefaction behavior between the two types of soil can be attributed to the variation in their permeability and plastic deformation capacity.The permeability coefficient and compression modulus of silt are lower than those of silty fine sand.Consequently,silt is more prone to the accumulation of pore pressure and subsequent liquefaction under external loading.Prior research has demonstrated that silt beds with varying consolidation degrees exhibit distinct initial failure modes.Specifically,a dense bed undergoes shear failure,whereas a loose bed experiences initial liquefaction failure.This study utilized discrete element simulation to examine the microscopic mechanisms that underlie this phenomenon.

A Prediction-Based Multi-Objective VM Consolidation Approach for Cloud Data Centers

Virtual machine(VM)consolidation aims to run VMs on the least number of physical machines(PMs).The optimal consolidation significantly reduces energy consumption(EC),quality of service(QoS)in applications,and resource utilization.This paper proposes a prediction-basedmulti-objective VMconsolidation approach to search for the best mapping between VMs and PMs with good timeliness and practical value.We use a hybrid model based on Auto-Regressive Integrated Moving Average(ARIMA)and Support Vector Regression(SVR)(HPAS)as a prediction model and consolidate VMs to PMs based on prediction results by HPAS,aiming at minimizing the total EC,performance degradation(PD),migration cost(MC)and resource wastage(RW)simultaneously.Experimental results usingMicrosoft Azure trace show the proposed approach has better prediction accuracy and overcomes the multi-objective consolidation approach without prediction(i.e.,Non-dominated sorting genetic algorithm 2,Nsga2)and the renowned Overload Host Detection(OHD)approaches without prediction,such as Linear Regression(LR),Median Absolute Deviation(MAD)and Inter-Quartile Range(IQR).

Spatiotemporal variations in ecosystem services and their trade-offs and synergies against the background of the gully control and land consolidation project on the Loess Plateau,China

Studying the spatiotemporal variations in ecosystem services and their interrelationships on the Loess Plateau against the background of the gully control and land consolidation(GCLC)project has significant implications for ecological protection and quality development of the Yellow River Basin.Therefore,in this study,we took Yan'an City,Shaanxi Province of China,as the study area,selected four typical ecosystem services,including soil conservation service,water yield service,carbon storage service,and habitat quality service,and quantitatively evaluated the spatiotemporal variation characteristics and trade-offs and synergies of ecosystem services from 2010 to 2018 using the Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)model.We also analysed the relationship between the GCLC project and regional ecosystem service changes in various regions(including 1 city,2 districts,and 10 counties)of Yan'an City and proposed a coordinated development strategy between the GCLC project and the ecological environment.The results showed that,from 2010 to 2018,soil conservation service decreased by 7.76%,while the other three ecosystem services changed relatively little,with water yield service increasing by 0.56% and carbon storage service and habitat quality service decreasing by 0.16% and 0.14%,respectively.The ecological environment of Yan'an City developed in a balanced way between 2010 and 2018,and the four ecosystem services showed synergistic relationships,among which the synergistic relationships between soil conservation service and water yield service and between carbon storage service and habitat quality service were significant.The GCLC project had a negative impact on the ecosystem services of Yan'an City,and the impact on carbon storage service was more significant.This study provides a theoretical basis for the scientific evaluation of the ecological benefits of the GCLC project and the realization of a win-win situation between food security and ecological security.

Substantive Consolidation in Bankruptcy of Affiliated Enterprises: The Dilemmas of Judicial Application and Improvements of the Criteria

No consensus has been reached in the academic community regarding the principles and criteria for the application of substantive consolidation in bankruptcy.However,in judicial practices,the substantive consolidation doctrine has been applied to handle enterprise bankruptcy cases.This paper summarizes the dilemmas in the judicial application of substantive consolidation in bankruptcy through case analyses.The paper also proposes pathways for improving the judicial application criteria for the substantive consolidation in bankruptcy of affiliated enterprises in China,that is,comprehensively assessing the degree of corporate personality confusion from multiple perspectives;considering the cost and difficulty of asset segregation as supplementary elements;weighing the protection of creditors’interests;and taking into account the feasibility and necessity of consolidation and reorganization.

Urban Freight Consolidation Model for Post-Hauler Planning

Freight transportation in urban areas has increased significantly in a shorter period due to the widespread use of e-commerce, fast delivery, and population growth. Recently, a noticeable government initiative aimed at creating an effective, acceptable, and sustainable city logistics policy. This paper examines freight consolidation as a transportation strategy for optimizing last-mile delivery costs. Freight consolidation involves combining smaller shipments from various origins into a single, larger shipment for more efficient transportation to a common destination. This approach is particularly beneficial for last-mile delivery, where frequent deliveries of smaller quantities are frequently visible. Finally, we provide an illustrative example targeting urban freight stakeholders for practicing possible consolidation methodology. The result in the illustrative example shows that freight with 3-day consolidation, despite the delay penalty, is cheaper than daily shipping, and both are cheaper than 2-day consolidated shipping. The study will benefit urban businesses and freight services.

Mechanism Analysis of Pore Water Pressure Fluctuation During Clay Precompression Consolidation

Pore water pressure fluctuations are an inherent phenomenon during the consolidation process of clayey foundations, and understanding its mechanism is crucial for comprehending the consolidation process and addressing issues such as drainage blockage during consolidation. This study investigates the consolidation behavior of clay, particularly focusing on pore water pressure fluctuations during the consolidation process of dredged marine sedimentary mud from Daya Bay, Guangdong Province. Given the prevalent use of clay in large-scale construction projects in southern China, understanding the factors influencing pore water pressure is crucial for optimizing consolidation times and improving construction efficacy. Using a custom vacuum preloading model, the research explores the impact of sodium hydroxide on the bound water content and its subsequent effects on pore water pressure dynamics. Experimental findings reveal a distinct inflection point in pore water pressure dissipation, suggesting that particle migration and bound water interactions contribute to the observed fluctuations. These results provide valuable insights for enhancing engineering applications in clay consolidation and mitigating drainage issues, ultimately informing construction practices and reducing project timelines.

真空热固结联合强夯处理工程废浆试验研究

为解决真空热固结过程中热量与真空负压在土体中衰减而导致土体加固效果不均匀的问题,利用强夯法能改善土体密实度的特性,将真空热固结法与强夯法联合应用于工程废浆的加固处理,通过4组室内模型试验研究不同夯击时机对土体加固效果的影响。结果表明:沉降速率为每3 d沉降4 cm时为最佳夯击时机,土体表面沉降比其他试验组提高26.55%、11.72%和3.74%,对工程废泥浆的处理效果最佳,能有效解决真空热固结下深层土体加固效果差的问题,并提高土体的均匀性。通过微观结构分析发现,合适的夯击时机下,由于土颗粒之间的孔隙重分布,导致土体密实程度更高,十字板剪切强度随之增大。此外,内部孔隙重分布产生微裂缝形成的排水通道对排水有一定的促进作用,进一步提升了固结效果,在合适的夯击时机下,对土体的十字板剪切强度与固结度均有促进作用。

Measuring technical efficiency of Chinese nonferrous metals enterprises on a background of industry consolidation

Since 2009, Chinese nonferrous metals industry has been carried out industry consolidation with strong support by the central government. This work examined technical efficiency of Chinese nonferrous metals firms and its change during the period of 2007 and 2011. Based on financial data from nonferrous metals listed companies, technical efficiency of nonferrous metal minerals mining firms and nonferrous metal smelting, pressing and processing firms was estimated respectively using the data envelopment analysis （DEA） method. It was found that, in both sectors, number of pure technical and scale inefficient firms dominated over efficient ones. Overall, their technical and scale efficiency tended to be very low after 2009. In particular, efficiency scores of nonferrous metal smelting, pressing and processing firms fluctuated greatly during the research period. And a limited number of large leading firms were able to maintain 100% efficiency score in the industry, while efficiency of most of other leading firms has declined since 2009.

考虑泊松效应的流泥轴对称真空过滤理论

真空预压处理流泥地基时,仅排水板附近的土体得到明显加固,以排水板为轴线形成一个凸出地表的“土柱”。土柱作为流泥地基真空预压处理的特有现象,导致流泥地基淤堵严重、处理效果差。根据流泥固液两相的连续、运动、平衡以及土柱移动边界方程,并考虑土柱土体泊松效应,在柱坐标系下建立了流泥轴对称真空过滤模型,获得了流泥地基真空预压过程中的土柱生长规律和土柱淤堵性状,并与PIV试验进行了对比验证。结果表明:土柱内渗透系数降幅高达97%,致密土柱是淤堵的本质;泊松效应和真空荷载幅值对土柱半径以及流泥固结效果的影响十分明显;低幅值真空荷载有利于形成半径小且较为疏松的淤堵区,从而缓解淤堵性状。

Influence of twist extrusion process on consolidation of pure aluminum powder in tubes by equal channel angular pressing and torsion

In comparison with the conventional equal channel angular pressing（ECAP） process,a comprehensive study of influence of twist extrusion（TE） process on consolidating pure aluminum powder in tubes（PITs） by equal channel angular pressing and torsion（ECAPT） was conducted via three-dimensional（3D） finite element simulation,experimental investigation and theoretical analysis.Simulation results revealed that during the consolidation of aluminum powder particles by ECAPT,TE process played a significant role of back pressure.Due to the torsional shear and high hydrostatic pressure exerted by twist channel,both the magnitude and homogeneity of the effective strain were increased markedly.After one pass of ECAPT process using a square channel with an inner angle of 90° and a twist slope angle of 36.5° at 200℃,commercial pure aluminum powder particles were successfully consolidated to nearly full density.Simulation and experimental results showed good agreement.In the microstructure observations,grains were greatly refined.At the same time,porosities were effectively eliminated by shrinking in size and breaking into small ones.Microhardness test indicated that strain distribution of ECAPT-processed billet was more homogeneous with respect to the ECAP-processed one.All these improvements may be attributed to the extreme intense shear strain induced during ECAPT and the increase in self-diffusion coefficient of aluminum due to the back pressure exerted by TE process.

Use of piezocone tests to predict consolidation yield stress and overconsolidation ratio of lagoonal deposit soil

Existing empirical methods for interpreting the consolidation yield stress and the overconsolidation ratio （OCR） in clays from piezocone tests are briefly reviewed. It can be seen that no universal correlation exists for all worldwide sites. However, for a given clay deposit, there does exist a most appropriate method to reflect the consolidation yield stress and the OCR based on piezocone test data. Three empirical methods are compared based on the piezocone test data collected on Lixia River lagoonal deposit soil sites in the north of Jiangsu province. The objective of this study is to evaluate the validity of the existing relationships linking the consolidation yield stress to piezocone test data and identify the appropriate method for Lixia River lagoonal deposit soil. It is shown that the correlation based on the net tip resistance has much higher accuracy for estimating the consolidation yield stress of lagoonal deposit soil than other methods.

饱和土不排水计算理论与方法探究

饱和土不排水强度及变形计算是岩土工程中颇具难度的复杂课题,至今业内对其多方面的问题仍存争议。结合笔者多年的相关学习研究,对此课题进行了较系统深入的探究。首先讨论了饱和土不排水计算的总应力法与有效应力法及各自的局限,并从有限元基本方程阐述了孔隙水压的处理,指出不管采用何种方法均应注意区分两类孔隙水压和两种总应力,即“土水分算”。随后,审视了Skempton-Henkel超静水压计算公式对不同应力路径的计算准确性,将它与MC强度准则相结合构建了饱和土不排水强度模型,对等向固结与不等向固结下饱和土不排水强度特性进行了分析,可为实际工程计算中强度参数选取提供参考。建议实际不排水计算采用广义Tresca强度准则,针对采用MC强度准则按有效应力法进行不排水计算会有较大误差的问题,除指出应直接输入不排水强度外,还给出一种采用等代强度参数的处理方法。在上述讨论基础上,剖析了固结不排水强度指标(CU指标)的缺陷,指出仅当土中总应力路径与测定CU指标的试验中相同时,用此指标直接计算才能给出准确的结果,特别是对地基承载力问题直接用此指标计算会给出严重偏危险的结果。还对基坑工程中主动、被动土水压力采用CU指标并土水合算的问题进行了分析,建议了合理计算方法及相应公式;对发生不排水极限土压时的滑移面倾角这一业内多人深感困惑的问题也进行了探讨。最后,针对饱和地基承载力及短期沉降计算,剖析了业内现行方法的问题,在深入解读有关因素影响机理的基础上给出新的计算方法。所给承载力计算公式,可较准确统一计算排水和不排水条件下的承载力,能更好保证设计的安全经济;所给沉降计算新方法能较准确计算饱和地基的短期沉降,对地基的排水沉降也可望取得较好结果,值得进一步发展完善。

Effect of consolidation parameters on mechanical properties of Cu-based bulk amorphous alloy consolidated by hot pressing

Cu50Zr40Ti10 bulk amorphous alloys were fabricated by hot pressing gas-atomized Cu50Zr40Ti10 amorphous powder under different consolidation conditions without vacuum and inert gas protection. The consolidation conditions of the Cu50Zr40Ti10 amorphous powder were investigated based on an L9（34） orthogonal design. The compression strength and strain limit of the Cu50Zr40Ti10 bulk amorphous alloys can reach up to 1090.4 MPa and 11.9 %, respectively. The consolidation pressure significantly influences the strain limit and compression strength of the compact. But the mechanical properties are not significantly influenced by the consolidation temperature. In addition, the preforming pressure significantly influences not the compression strength but the strain limit. The optimum consolidation condition for the Cu50Zr40Ti10 amorphous powder is first precompacted under the pressure of 150 MPa, and then consolidated under the pressure of 450 MPa and the temperature of 380 °C.

Refinement and consolidation of pure Al particles by equal channel angular pressing and torsion

Consolidation of pure Alpowder was conducted at 200 ℃ by equal channel angular pressing and torsion （ECAPT） method. The grain refinement and consolidation behavior were deeply investigated by scan electronic microscopy （SEM） and transmission electronic microscopy （TEM）. The density, hardness and room temperature compression properties of the deformed samples were measured. The experiment results show that ECAPT is an effective method of consolidating powders at relatively low temperatures. Pure A1 particles are successfully consolidated into dense bulk material after 4 passes of ECAPT at 200 ℃. The consolidated material possesses fine grain structure and excellent mechanical properties. The refinement and consolidation mechanisms were analyzed. ECAPT is a promising method to produce the high-performance bulk materials from particles.

无人机倾斜摄影测量技术在土地整理中的应用分析

无人机倾斜摄影测量技术可以实现自动快速获取各种复杂的地形图和高程特征点,进而快速完成土方量计算。本文以某区域为例,使用大疆精灵四RTK无人机进行“井”字形飞行获取倾斜摄影数据,利用Context Capture建模软件对数据进行处理,得到三维模型和正射影像数据,在EPS软件中利用三维模型等数据进行土方量计算,快速得到土方量计算结果。以RTK实测数据为真值,检验无人机倾斜摄影测量土方量计算结果的可靠性和准确性。两种测量方法计算的填方量相对误差2.7%、挖方量相对误差7.8%,小于10%的限差范围,均符合土方工程规范要求。以上结果表明,利用无人机倾斜摄影计算土方量,其结果满足土方工程规范要求,且工作效率高、成本低,可为相关土地整理项目提供技术参考。

整体性治理视域下巩固拓展脱贫攻坚成果与乡村振兴有效衔接研究

2020年年底,我国全面打赢脱贫攻坚战后全面建成小康社会,巩固拓展脱贫攻坚成果与乡村振兴有效衔接成为目前重要且紧迫的工作任务。巩固拓展脱贫攻坚成果与乡村振兴衔接具有跨领域性和多元繁杂性,二者衔接存在政策衔接不畅、资源配置分散、行动实践缺乏双向协同、治理结构模糊等“碎片化”问题。破解二者衔接所凸显的“碎片化”现象亟须借助于以“承担公共责任,满足公众需求”为根本指向,以“协调、整合”为核心的整体性治理理论提供解决思路。因此,基于整体性治理视角提出解决二者衔接进程中“碎片化”问题的关键举措:整合政策冲突,做实政策衔接;加强资源整合,实现资源有效衔接;健全协同合作的工作机制,确保行动精确衔接;优化组织协同,构筑多元治理结构。为巩固拓展脱贫攻坚成果和乡村振兴的全面实施,加快农业农村现代化建设和实现全民共同富裕提供实践研究。

职业教育赋能巩固拓展脱贫攻坚成果的路径研究

当前,我国虽然完成了消除绝对贫困的艰巨任务,但相对贫困仍将长期存在。新阶段,必须做好巩固拓展脱贫攻坚成果、防止规模性返贫致贫的工作。在此背景下,进一步发展职业教育不仅能切实推进“固脱防返”取得实效,更能通过促进个体长远发展和乡村全面振兴。职业教育必须强化可持续发展的理念,加强相对贫困源头治理,提升职业教育多元供给能力,重点关注脱贫人口的精神生活,从根本上切实巩固拓展脱贫攻坚成果。

Problems and Significance of Land Consolidation Projects Quality and Countermeasures

Land consolidation program would not only increase farmland area, but also improve land quality. With consideration of problems in land consolidation, such as highlighting number and ignoring quality, and compensating poor farmlands for occupied highly-qualified farmlands, the research proposed the importance of quality of land consolidation program and the way for improving the quality, in order to draw attention of national land consolidation industry for quality of the program, protect farmlands and crop safety, and advance social stability and harmony.