Pseudo-dynamic analysis of seismic stability of reinforced slopes considering non-associated flow rule

The required reinforcement force to prevent instability and the yield acceleration of reinforced slopes are computed under seismic loading by applying the kinematic approach of limit analysis in conjunction with the pseudo-dynamic method for a wide range of soil cohesion, friction angle, dilation angle and horizontal and vertical seismic coefficients. Each parameter threatening the stability of the slope enhances the magnitude of the required reinforcement force and vice versa. Moreover, the yield acceleration increases with the increase in soil shear strength parameters but decreases with the increase in the slope angle. The comparison of the present work with some of the available solutions in the literatures shows a reasonable agreement.

Energy analysis of rock plug thickness in karst tunnels based on non-associated flow rule and nonlinear failure criterion

The geological hazards, such as water inrush and mud outburst, are easily induced by the high water pressure caverns ahead of a karst tunnel face. Therefore, it is a pivotal issue to determine the reserved thickness of rock plug during the construction of tunnels. The limit analysis principle is employed to analyze the safe thickness from the point of energy dissipation, and the nonlinear and non-associated characteristics of geotechnical materials are both considered. On the basis of a plane failure pattern of rock plug, the expressions of detaching curve and rock plug thickness are derived. The effect of each parameter on the safe thickness of rock plug is discussed in detail, which interprets the corresponding failure scope of rock plug. The obtained results indicate that the thickness of rock plug is highly influenced by the nonlinear dilatancy coefficient and the nonlinear coefficient. The proposed method is validated by a comparison of the calculated results with those of the engineering project of the "526 karst cavern" of Yunwushan tunnel. This proposed method can provide reference basis for the design and excavation of karst tunnels in the future.

Energy analysis of stability on shallow tunnels based on non-associated flow rule and non-linear failure criterion

On the basis of upper bound theorem, non-associated flow rule and non-linear failure criterion were considered together.The modified shear strength parameters of materials were obtained with the help of the tangent method. Employing the virtual power principle and strength reduction technique, the effects of dilatancy of materials, non-linear failure criterion, pore water pressure,surface loads and buried depth, on the stability of shallow tunnel were studied. In order to validate the effectiveness of the proposed approach, the solutions in the present work agree well with the existing results when the non-associated flow rule is reduced to the associated flow rule and the non-linear failure criterion is degenerated to the linear failure criterion. Compared with dilatancy of materials, the non-linear failure criterion exerts greater impact on the stability of shallow tunnels. The safety factor of shallow tunnels decreases and the failure surface expands outward when the dilatancy coefficient decreases. While the increase of nonlinear coefficient, the pore water pressure coefficient, the surface load and the buried depth results in the small safety factor. Therefore, the dilatancy as well as non-linear failure criterion should be taken into account in the design of shallow tunnel supporting structure. The supporting structure must be reinforced promptly to prevent potential mud from gushing or collapse accident in the areas with abundant pore water, large surface load or buried depth.

The study of slip line field and upper bound method based on associated flow and non-associated flow rules

At present, associated flow rule of traditional plastic theory is adopted in the slip line field theory and upper bound method of geotechnical materials. So the stress characteristic line conforms to the velocity line. It is proved that geotechnical materials do not abide by the associated flow rule. It is impossible for the stress characteristic line to conform to the velocity line. Generalized plastic mechanics theoretically proved that plastic potential surface intersects the Mohr-Coulomb yield surface with an angle, so that the velocity line must be studied by non-associated flow rule. According to limit analysis theory, the theory of slip line field is put forward in this paper, and then the ultimate beating capacity of strip footing is obtained based on the associated flow rule and the non-associated flow nile individually. These two results are identical since the ultimate bearing capacity is independent of flow role. On the contrary, the velocity fields of associated and non-associated flow rules are different which shows the velocity field based on the associat- ed flow rule is incorrect.

Modified Burzynski criterion with non-associated flow rule for anisotropic asymmetric metals in plane stress problems

The Burzynski criterion is developed for anisotropic asymmetric metals with the non-associated flow rule （NAFR） for plane stress problems. The presented pressure depending on the yield criterion can be calibrated with ten experimental data, i.e., the tensile yield stresses at 0°, 45°, and 90°, the compressive yield stresses at 0°, 15°, 30°, 45°, 75°, and 90° from the rolling direction, and the biaxial tensile yield stress. The corresponding pressure independent plastic potential function can be calibrated with six experimental data, i.e., the tensile R-values at 0°, 15°, 45°, 75°, and 90° from the rolling direction and the tensile biaxial R-value. The downhill simplex method is used to solve these ten and six high nonlinear equations for the yield and plastic potential functions, respectively. The results show that the presented new criterion is appropriate for anisotropic asymmetric metals.

Digital Development Rights in Developing Countries:Where the Governance Rules for Cross-Border Data Flows

The digital development rights in developing countries are based on establishing a new international economic order and ensuring equal participation in the digital globalization process to achieve people's well-rounded development in the digital society.The relationship between cross-border data flows and the realization of digital development rights in developing countries is quite complex.Currently,developing countries seek to safeguard their existing digital interests through unilateral regulation to protect data sovereignty and multilateral regulation for cross-border data cooperation.However,developing countries still have to face internal conflicts between national digital development rights and individual and corporate digital development rights during the process of realizing digital development rights.They also encounter external contradictions such as developed countries interfering with developing countries'data sovereignty,developed countries squeezing the policy space of developing countries through dominant rules,and developing countries having conflicts between domestic and international rules.This article argues that balancing openness and security on digital trade platforms is the optimal solution for developing countries to realize their digital development rights.The establishment of WTO digital trade rules should inherently reflect the fundamental demands of developing countries in cross-border data flows.At the same time,given China's dual role as a digital powerhouse and a developing country,it should actively promote the realization of digital development rights in developing countries.

Seismic failure mechanisms for loaded slopes with associated and nonassociated flow rules

Seismic failure mechanisms were investigated for soil slopes subjected to strip load with upper bound method of limit analysis and finite difference method of numerical simulation,considering the influence of associated and nonassociated flow rules.Quasi-static representation of soil inertia effects using a seismic coefficient concept was adopted for seismic failure analysis.Numerical study was conducted to investigate the influences of dilative angle and earthquake on the seismic failure mechanisms for the loaded slope,and the failure mechanisms for different dilation angles were compared.The results show that dilation angle has influences on the seismic failure surfaces,that seismic maximum displacement vector decreases as the dilation angle increases,and that seismic maximum shear strain rate decreases as the dilation angle increases.

Influences of nonassociated flow rules on seismic bearing capacity factors of strip footing on soil slope by energy dissipation method

Seismic bearing capacity factors of a strip footing placed on soil slope were determined with both associated and nonassociated flow rules. Quasi-static representation of earthquake effects using a seismic coefficient concept was adopted for seismic bearing capacity calculations. A multi-wedge translational failure mechanism was used to obtain the seismic bearing capacity factors for different seismic coefficients and various inclined angles. Employing the associated flow rule, numerical results were compared with the published solutions. For bearing capacity factors related to cohesion and equivalent surcharge load, the maximum difference approximates 0.1%. However, the difference of bearing capacity factor related to unit weight is larger. With the two flow rules, the seismic bearing capacity factors were presented in the form of design charts for practical use. The results show that seismic bearing capacity factors related to the cohesion, the equivalent surcharge load and the unit weight increase greatly as the dilatancy angle increases, and that the nonassociated flow rule has important influences on the seismic bearing capacity.

Influences of nonassociated flow rules on three-dimensional seismic stability of loaded slopes

The influences of soil dilatancy angle on three-dimensional （3D） seismic stability of locally-loaded slopes in nonassociated flow rule materials were investigated using a new rotational collapse mechanism and quasi-static coefficient concept. Extended Bishop method and Boussinesq theorem were employed to establish the stress distribution along the rupture surfaces that are required to obtain the rate of internal energy dissipation for the nonassociated flow rule materials in rotational collapse mechanisms. Good agreement was observed by comparing the current results with those obtained using the translational or rotational mechanisms and numerical finite difference method. The results indicate that the seismic stability of slopes reduces by decreasing the dilatancy angle for nonassociated flow rule materials. The amount of the mentioned decrease is more significant in the case of mild slopes in frictional soils. A nearly infinite slope under local loading, whether its critical failure surface is 2D or 3D, not only depends on the magnitude of the external load, but also depends on the dilataney angle of soil and the coefficient of seismic load.

AN APPLICATION OF TOPOLOGICAL ANALYSIS TO STUDYING THE THREE-DIMENSIONAL FLOW IN CASCADES;PART I—TOPOLOGICAL RULES FOR SKIN-FRICTION LINES AND SECTION STREAMLINES

Based on the working of Lighthill and Hunt et al., in the present paper the author has established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades. These rules are (1) for a rotor cascade without shroud band, the total number of nodal points equals that the saddle points on the skin-friction line vector fields in eachpitch range; (2) for an annular or straight cascade with no-clearances at blade ends, the total number of saddle points is two more than that of nodal points on the skin-friction line fields in a pitch; (3) the total number of saddles in the secondary flow fields on cross-sections in cascade is one less than that of nodes; (4) in the section streamline vector fields on a meridian surface penetrating a flow passage, and on leading and trailing edge sections, the total number of nodes is equal to that of saddles; (5) on the streamline vector fields of a blade-to-blade surface, the total number of nodes is one less than that of saddles.

相变:生产方式如何塑造财产规则

当前关于数字时代财产权利的讨论持续不断,基本上可以分为两种类型:一种是针对较为具体的虚拟物品(如信息内容、游戏装备、账号、数据、虚拟币等),在特定场景中沿着既有法律框架或概念进行分析;一种则试图在原理上阐明数字时代究竟何种对象能够适用财产规则进行更好的保护,以及这种财产规则的构成要件为何,如按照“权利束”或“模块化”框架加以应用。有必要转换角度提问,即成熟的财产权利制度出现,不是因为法律研究主张为何种事物或利益赋予财产权就能自动实现,而是赋权的外部环境成熟了,才会催生相关利益主体提出主张,并推动相关利益在法律上得到确认和保护。违背生产秩序的产权结构和财产规则不可能出现在数字时代,在生产方式进行巨大调整时,财产规则和其他部门法律规则一样,都面临着双重历史任务:一是“破”,即挑战并打破传统制度,允许要素超越既有生产过程低成本流动;一是“立”,即根据生产方式要求树立反映特殊性的新制度,重新商定哪些要素和利益允许参与者继续占有和使用,划定边界。

RTAs框架下跨境数据流动规则对数字服务贸易的影响研究

文章基于2010—2021年全球50个代表性经济体的双边数字服务出口数据,采用引力模型实证检验了跨境数据流动规则的贸易创造效应。结果表明:缔约国之间签订的RTAs中,跨境数据流动规则的承诺水平越高,双边数字服务贸易规模越大,贸易创造效应越显著;将跨境数据流动规则细分为数据流动规则、数据本地化规则和数据保护规则后发现,数据本地化条款对数字服务贸易的促进作用更强;相较于其他部门,跨境数据流动规则对金融服务的贸易促进作用更强;缔约国整体的经济自由度水平越高,跨境数据流动规则对数字服务贸易的促进效应越小;缔约国之间的数据监管环境差距越大,跨境数据流动规则越能促进双边数字服务贸易发展。机制检验结果表明:跨境数据流动规则能够通过降低贸易成本、缩短制度距离和扩大出口国的双向FDI规模促进数字服务贸易发展。研究结论证实了跨境数据流动规则产生的贸易创造效应,为我国有效制定数字服务贸易开放政策、积极参与全球数字治理提供了经验证据。

北京延庆泥石流隐患分布规律及演化趋势研究

泥石流是一种具有强烈破坏性的山区突发性地质灾害现象,是北京山区较严重、危害性较大的地质灾害类型之一。北京延庆泥石流灾害的研究主要针对局部或单流域泥石流沟,区域性的泥石流隐患特征、分布规律以及演化特征等研究工作极少。以北京延庆泥石流隐患为研究对象,旨在为延庆山区泥石流灾害预警预报和防灾减灾提供理论依据。通过收集延庆泥石流隐患相关文献资料,实际调查泥石流隐患发育特征,系统分析延庆泥石流灾害的孕灾背景情况,梳理自然地理、地质背景及人类活动之间的内在联系,查明泥石流隐患的沟域和物源特征,研究泥石流隐患所在流域的地貌形态、地形坡度、降雨条件及地层岩性的分布特征,探究泥石流、水石流和发育期、衰退期泥石流隐患的物源分布规律,查清泥石流隐患的物源转化过程,掌握延庆主要处于发育期和衰退期的泥石流隐患演化趋势。研究结果表明:延庆泥石流隐患属于暴雨型-沟谷型-支沟群发型泥石流,泥石流规模大小与流域地形地貌、松散堆积物累积、动态变化以及暴雨情况相关,研究成果可为泥石流调查研究、预测预报和监测预警提供科学依据和技术参考。

数据跨境流通规则博弈与中国应对

如何安全有效促进数据跨境流通和赢得数据跨境流通治理话语权主导权,成为各国博弈的焦点。当前,受各国数据治理理念,核心利益诉求,深层次个人数据安全、国家数据主权、数据跨境自由流通不可兼得的“三元悖论”以及传统数据治理手段制约,国际数据跨境流通领域形成多元治理机制并存、多套治理模板竞争、多轮博弈持续演进的博弈态势,以及数据跨境流通治理碎片化割裂化的局面。当前,我国以国家安全与数据跨境有序自由流动并重为基本特征的数据跨境流通治理主张,不仅契合我国发展实际,而且符合大多数发展中国家的愿望。总体而言,数据跨境流通治理中国方案是一种合意的数据跨境流通治理方案,但在具体实践中我国数据跨境流通治理依然存在一些短板,如有些规定不太合理导致企业数据跨境流通操作成本高、数据跨境流通治理参与度低导致数据跨境流通互操作性较差、与国际高标准数字经贸规则存在衔接障碍等,同时面临国际上异样的声音,甚至存在被污名化、被打压的风险,不利于数据跨境流通治理中国方案效力与国际影响力的提升。为在数据跨境流通治理领域赢得话语权主导权、推进数据跨境流通国际治理,我国应坚持多边主义,推动以联合国和WTO为主导的国际机制建设;推进“数字丝绸之路”建设,扩大中国方案影响力;加强双多边合作,增强数据跨境流通互操作性;对接高标准数字经贸规则,提高数据跨境流通治理能力。

基于关联规则挖掘的终端区交通拥挤传播规律研究

本文基于空中交通流运行现象建立交通拥挤传播规则挖掘模型,从数理角度分析并表征终端区交通流拥挤状态的传播现象。首先,对终端区交通流按照航段结构进行划分并给出交通状态评价指标,采用模糊C均值算法对终端区进场交通流状态进行聚类划分;其次,使用OApriori算法挖掘终端区进场交通流拥挤传播规则;最后,基于实测历史数据构建北京终端区全空域及机场模型(TAAM,total airspace and airport modeler)仿真场景,模拟终端区在不同流量分布特征下的运行情况并进行分析,结果表明:本文模型分析所得的传播规律与实际情况相符,并发现优化终端区进场点流量分布能显著减少终端区拥挤状态的传播现象。

国际经济规则重建的底层逻辑:历史演进与现实挑战

2008年全球金融危机暴发后,国际经济规则进入了战后以来的重大调整期。国际组织与主要经济体都试图推出符合自身利益的规则以提升治理话语权。本文梳理了二战以来国际经济秩序的变迁及不同时期国际经济规则的特征与演化过程,从各项规则、规制和标准的制定和实施过程看,效率与安全优先顺序的交替转变是造成国际经济规则演变的重要底层逻辑;从多边体系、区域组织、自贸试验区和企业标准四方面提出国际经济规则重建的路径,指出国际经济规则重建面临着国内主权保护与国际规则约束、长短期利益不一致的冲突。中国参与国际经济规则重建面临着突破西方围堵与平衡长短期利益的挑战。中国需要坚定秉持构建人类命运共同体理念,积极调整参与国际经济规则谈判的策略,推进全球多边治理体系改革,为构建公正合理的全球经济秩序提出中国方案。

粤港澳大湾区规则衔接的实践审视与路径优化

粤港澳大湾区建设具有双重意涵和定位,在经济层面旨在实现要素高效有序流动,同时型构动态综合体系化的三圈层法治秩序。《粤港澳大湾区发展规划纲要》发布五年来,规则衔接从多个维度出发,综合运用多种方式于多个领域内逐渐铺开,初步打破地区间壁垒,但仍存在未实质性打破行政壁垒、衔接缺乏融贯性、各地协同性不足,以及要素流动全链条衔接和湾区法治体系全面建构不足的问题,其根本原因为湾区间法治体系差异较大,主要原因是统筹协调不足导致规则衔接顶层设计缺失,直接原因则是体制机制不健全制约规则衔接的实效。粤港澳大湾区建设迈入纵深发展新阶段,宏观上应当以宪法为统领构筑湾区法治秩序,中观上应以全要素有序流动为具体标准构建规则衔接体系,并依托体制改革和微观机制创新达致规则衔接的根本突破。

个人信息出境的国内法规制路径及体系化完善

数字化个人信息的大规模跨境传输使得个人权益、公共利益和国家安全利益受损的风险加剧,国际社会尚未达成统一法律规范予以应对。为维护国家数据主权、促进数据产业发展与保障个人信息安全,各国选择以国内法规制的方式对个人信息出境予以监管,具体表现为国家专门立法、联盟统一立法与国家分散立法。我国通过专门立法规制个人信息出境,形成了“硬性”与“软性”两轨监管机制,但存在分轨监管内容交叉、公私共治监管尚未形成的问题,阻碍个人信息的安全出境。在统筹推进国内法治和涉外法治的背景下,我国应以系统观念加强个人信息出境监管建设,从主体上发挥公私体系的协同性,从规范上强化攻防体系的均衡性,从空间上增进内外体系的互动性,为促成个人信息跨境规制的多边共识贡献中国智慧。

数据跨境流动的约束性企业规则研究

欧盟《一般数据保护条例》确立的约束性企业规则是欧盟个人数据跨境传输规则中的适当保障措施之一,它作为数据跨境流动的合规工具具有显著优势。我国自2021年施行的《个人信息保护法》中仅参照引入了标准合同条款,约束性企业规则还未明确在我国法律中引入。为了便利我国企业“走出去”,我国应引入约束性企业规则。为此,我国应明确约束性企业规则的上位法依据,同时合理借鉴他国实践经验,打造中国式约束性企业规则。

数字贸易国际规则博弈与中国因应——基于制度型开放视角

数字经济时代,数字贸易成为经济增长的新引擎,而制度规则因素则成为影响数字贸易高质量发展的关键因素。美西方国家凭借在数字服务贸易方面的领先优势,推行以跨境数据自由流动为核心的数字贸易规则,以获取更大的贸易利得。我国数字贸易高质量发展面临的主要挑战是与发达经济体的数字贸易制度规则博弈加剧,与新兴经济体数字贸易合作因数字贸易水平差异形成的制度规则障碍,我国数字企业数据合规与跨境治理能力弱,“南方国家”规则自主性不高的反作用,以及数字贸易壁垒抑制效应凸显等。要在制度型开放引领下,增强我国数字贸易规则融合与引领能力,提升数字贸易企业数据合规与治理能力,推进国内数字贸易规则完善升级,推动与新兴经济体数字贸易合作,构建中国数字贸易的新质技术,加强我国数字贸易规则体系建设,为国际数字经济治理贡献中国方案。