An approach for determination of lateral limit angle in kinematic planar sliding analysis for rock slopes

Planar sliding is one of the frequently observed types of failure in rock slopes.Kinematic analysis is a classic and widely used method to examine the potential failure modes in rock masses.The accuracy of planar sliding kinematic analysis is significantly influenced by the value assigned to the lateral limit angleγlim.However,the assignment ofγlim is currently used generally based on an empirical criterion.This study aims to propose an approach for determining the value ofγlim in deterministic and probabilistic kinematic planar sliding analysis.A new perspective is presented to reveal thatγlim essentially influences the probability of forming a potential planar sliding block.The procedure to calculate this probability is introduced using the block theory method.It is found that the probability is correlated with the number of discontinuity sets presented in rock masses.Thus,different values ofγlim for rock masses with different sets of discontinuities are recommended in both probabilistic and deterministic planar sliding kinematic analyses;whereas a fixed value ofγlim is commonly assigned to different types of rock masses in traditional method.Finally,an engineering case was used to compare the proposed and traditional kinematic analysis methods.The error rates of the traditional method vary from 45%to 119%,while that of the proposed method ranges between 1%and 17%.Therefore,it is likely that the proposed method is superior to the traditional one.

A novel limiting strain energy strength theory

With applied dislocation theory,the effects of shear and normal stresses on the slide and climb motions at the same section of a crystal were analyzed.And,based on the synergetic effect of both normal and shear strain specific energies,the concept of the total equivalent strain specific energy(TESSE)at an oblique section and a new strength theory named as limiting strain energy strength theory(LSEST)were proposed.As for isotropic materials,the plastic yielding or brittle fracture of under uniaxial stress state would occur when the maximum TESSE reached the strain specific energy,also the expressions on the equivalent stresses and a function of failure of the LSEST under different principal stress states were obtained.Relationship formulas among the tensile, compressive and shear yield strengths for plastic metals were derived.These theoretical predictions,according to the LSEST,were consistent very well with experiment results of tensile,compressive and torsion tests of three plastic metals and other experiment results from open literatures.This novel LSEST might also help for strength calculation of other materials.

DEEP-DRAWING PROCESS ANALYSIS OF ELLIPTIC CUPS BY RIGID-PLASTIC FEM

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General Relativity as the Classical Limit of the Renormalizable Gauge Theory of Volume Preserving Diffeomorphisms

The different roles and natures of spacetime appearing in a quantum field theory and in classical physics are analyzed implying that a quantum theory of gravitation is not necessarily a quantum theory of curved spacetime. Developing an alternative approach to quantum gravity starts with the postulate that inertial energy-momentum and gravitational energy-momentum need not be the same for virtual quantum states. Separating their roles naturally leads to the quantum gauge field theory of volume-preserving diffeomorphisms of an inner four-dimensional space. The classical limit of this theory coupled to a quantized scalar field is derived for an on-shell particle where inertial energy-momentum and gravitational energy-momentum coincide. In that process the symmetry under volume-preserving diffeomorphisms disappears and a new symmetry group emerges: the group of coordinate transformations of four-dimensional spacetime and with it General Relativity coupled to a classical relativistic point particle.

A new calculation method for axial load capacity of separated concrete-filled steel tubes based on limit equilibrium theory

A new calculation method for axial load capacity of separated concrete-filled steel tubes based on limit equilibrium theory was proposed,which took into account the decrease of confinement effect by steel tube and the non-uniform distribution of ultimate stress in cored concrete.The accuracy of the analytical result is validated through running the numerical result by finite element method (FEM) and experimental data as well.The influences of the key parameters on the load capacity of the concrete-filled steel tube (CFST) was studied,including the separation ratio,concrete compressive strength,and steel strength.The results indicate that the load capacity of the tube increases with concrete strength and steel strength under the separation ratio less than 4%,while decreases with a higher separation ratio improved.

基于均匀化理论与上限分析的膨胀土滑坡稳定性分析

在膨胀土和滑坡共同作用下,隧道洞口段施工更容易引发地表开裂甚至滑坡等工程灾害,在隧道内采用微型桩群防治滑坡比抗滑桩具有优势。本文基于均匀化理论与上限分析对某高速公路隧道洞口段膨胀土滑坡的稳定性进行计算,并评价微型桩群和削方卸载不同组合方式的处置效果,计算时将微型桩群及桩周土通过均匀化理论等效为符合摩尔库仑强度准则的等效加固体来,以此提高计算效率,最后通过对现场削方+微型桩群加固处置后的滑坡变形监测来验证计算的合理性,得出如下结论:相较于土的强度参数,等效加固体内摩擦角保持不变,黏聚力从26kPa提高到85.36kPa。处置前后的滑坡稳定性评价结果表明,不做处理时,滑坡滑动面从滑坡上方岩土交界面延续到隧道洞口前;仅采用微型桩群加固时,滑坡安全系数在1.17左右,滑动面从岩土交界面延续到隧道洞口后;同时采用微型桩群加固和削方卸载时,滑坡安全系数提高到1.26~1.28,滑动面上缘由土石交界面前移。现场变形监测表明地表变形与深层土体变形均不超过3mm,该措施能保障滑坡的稳定性,同时也验证了计算方法的合理性,可为同类工程提供参考。

争议点理论的司法价值、应用及其限度

起源于古希腊法庭辩论实践的争议点理论既是司法论辩制度的理论升华,也是司法技术的具体延伸。就当事人而言,找准案件争议点可以促使当事人尽快熟悉司法问题而使得法庭论辩更具有针对性;就法官而言,确定案件争议点有利于聚焦问题并找到纠纷解决的有效方法;就司法而言,争议点理论强调对具体案件核心、关键问题进行有效争辩和对话,有利于事实澄清和法律的正确适用。作为一种实践性较强的理论既需要从法理上进行审视,也需要从实践操作当中予以重点关切。从司法应用以及具体案例中分析,争议点理论忽视了观点多元的可能性,实践过程中争议点的提出缺乏强制回应力,而且由于能力差异各方对争议点的理解也会有分歧。

基于极限平衡理论的陷落柱防水煤柱留设研究

为有效治理含水陷落柱的导水致灾现象,以平朔井工一矿4108工作面为背景,根据井下实际地质生产条件计算防水煤柱极限平衡宽度,从理论层面初步确定防水煤柱留设宽度,同时利用UDEC软件对不同宽度的煤柱塑性破坏进行数值模拟分析。模拟结果表明:当煤柱宽度达到40 m时,煤柱内的屈服区和周边裂隙带基本保持稳定,根据煤柱稳定性对弹性区宽度应大于14 m的要求,防水煤柱宽度应留设40 m;在煤柱宽度与弹性区宽度关系上,煤柱内弹性区的宽度随着煤柱宽度的增加而增加,当煤柱宽度大于40 m时,煤柱内屈服区与塑性区的宽度已基本稳定。4108工作面采用设计的绕过陷落柱方案,优化了绕过陷落柱工序,有效降低了煤炭资源的损失。

考虑不同失效模式的索杆结构构件面积缺损限值研究

索杆结构长期服役过程中的锈蚀会造成构件截面损失,导致结构内力的重新分配,影响结构的安全性能。文中基于可靠度理论与结构极限状态分别建立了构件强度失效、钢索松弛失效及节点变形失效3种失效模式,并得到了不同失效模式临界状态下的可靠度限值控制不等式;通过力学推导,给出了以缺损面积为变量的杆件内力与节点位移变化公式,依据该公式可计算出可靠度限值控制不等式中的影响系数矩阵;引入钢材的锈蚀模型并结合非线性规划,提出了一种确定索杆结构构件面积缺损限值的方法。对一Levy型索穹顶的构件面积缺损限值进行了算例分析,并与规范限值进行对比。结果表明:索杆结构中的多数构件在强度失效与变形失效模式下的面积缺损限值高于耐久性限值,但松弛失效模式下的构件面积缺损限值小于耐久性限值,如按该限值要求对结构进行设计及维护将有可能发生钢索松弛失效;而安全性限值对于钢索构件较为严格,对于钢杆构件则与耐久性限值相同。因此,需综合考虑3种失效模式与规范限值,并按最严格的结果进行控制。

马克思劳动价值论视域下内卷化现象的逻辑透析及突破路径--以限定产品为例

限定产品在“消费主义”包装下,使消费者陷入“符号消费”的漩涡,进而导致企业生产内卷化,引发市场的恶性竞争。基于马克思主义政治经济学来分析这一内卷化现象,其缘起于商品经济的供需不平衡,兴起于资本对剩余价值的狂热追逐,在消费主义符号化的推波助澜下,扩张于资本逻辑中生产和消费的辩证关系之中,进而发现内卷化本质是商品拜物教建制下的异化症候。解决限定产品市场乱象,应以马克思“人的解放学说”为理论要旨,通过重塑人民消费观念、积极推动品牌发展、深度融合中国文化、构建多元治理体系,从整体上支撑起社会消费的提质升级,形成高质量发展的消费经济动力。

3轨式横向对称分布6-PSS并联机构及性能优化

针对多滑块共轨式6-PSS并联机构存在的姿态工作空间小、容易奇异等问题,课题组提出一种3轨式分布的6-PSS并联机构(P为移动副,S为球副)。该并联机构杆件长度和轨道间距呈不均匀布置,以提升姿态工作空间;采用闭环矢量法进行位置分析,通过极限边界搜索法求解工作空间;基于运动/力传递指标对机构性能进行评估,并采用性能图谱法基于全域指标GTI进行机构尺寸优化。结果表明优化后机构运动/力传递性能有显著提升,同时姿态工作空间也得到提升。该机构在工程上有一定的实用性。

Effects of cement-enhanced soil on the ultimate lateral resistance of composite pile in clayey soil

The composite pile consisting of core-pile and surrounding cement-enhanced soil is a promising pile foundation in recent years.However,how and to what extent the cement-enhanced soil influences the ultimate lateral resistance has not been fully investigated.In this paper,the ultimate lateral resistance of the composite pile was studied by finite element limit analysis(FELA)and theoretical upper-bound analysis.The results of FELA and theoretical analysis revealed three failure modes of laterally loaded composite piles.The effects of the enhanced soil thickness,strength,and pile-enhanced soil interface characteristics on the ultimate lateral resistance were studied.The results show that increasing the enhanced soil thickness leads to a significant improvement on ultimate lateral resistance factor(N P),and there is a critical thickness beyond which the thickness no longer affects the N P.Increasing the enhanced soil strength induced 6.2%-232.6%increase of N P.However,no noticeable impact was detected when the enhanced soil strength was eight times higher than that of the natural soil.The maximum increment of N P is only 30.5%caused by the increase of interface adhesion factor(a).An empirical model was developed to calculate the N P of the composite pile,and the results show excellent agreement with the analytical results.

正当防卫限度条件的内涵解读及判断路径

我国《刑法》以及司法解释对于正当防卫限度条件的规定明确,但缺乏可操作性。“明显超过”指将不法侵害和防卫行为判处的刑期进行对比,中间跨过一个刑期档次即防卫行为过当;“必要限度”的解读即以必需说为理论基础并对其进行修正解释;而“重大损害”是将不法侵害可能造成的损害与防卫人实际造成的损害进行对比,以《刑法》规定的人体损伤标准为基准,二者对比结果跨越一个大档次即属于造成“重大损害”。对于是否超出防卫限度的判断总体上应坚持从行为→结果的层级式判断方法。

体卫融合服务开展的限制性因素分析——基于扎根理论的案例研究

目的:体卫融合作为促进全民健康的最佳路径之一,彰显出巨大的发展前景。然而实践中运动之于健康的优势并未得到充分发挥,因此提升服务效果迫在眉睫。方法:通过对常州市卫健委、常州市体育医院的管理人员和工作人员及其合作的社区的居民进行半结构化访谈,运用文献资料、扎根理论等方法,借助Nvivo11.0质性分析软件,对访谈记录进行程序化分析。结果:通过开放性编码抽象出40个概念和12个范畴,通过主轴编码进一步凝练,形成4个主范畴,分别为“政府”“服务机构”“服务人员”“民众”。通过对12个范畴、4个主范畴进行继续考察,确定出“体卫融合服务开展的限制性因素”这一核心范畴。以“各因素如何影响体卫融合服务以及各因素之间的相互影响”为线索,构建出体卫融合服务限制因素模型。结论:基于理论模型,提出疏解策略:应以“系统化”观念,加强全局谋划;以深耕迎合作,内外联动聚资源,建立长效机制;优制度促发展,激发主观能动性,提升服务品质;强化主体认同,引导民众主动参与。

婚姻住房的处分限制:信托视角的考察

婚姻住房是夫妻共同生活的基本场所,我国目前的法律对婚姻住房保护不足。考虑事实和价值层面探讨限制处分婚姻住房的正当性,借鉴大陆法系的典型国家法国和德国以及英美法系的英国的立法和司法实践,以信托角度探讨保护婚姻住房的途径及措施,对婚姻住房处分限制的措施进行立法反思和信托法理的适用分析,通过对信托法理的援用、参照,达到补充法律缺失的功能。

山后矿区基于厚板理论的进路极限跨度设计研究

该文主要研究的是深部金属矿的采场设计问题。在开采过程中,进路宽度设计不合理会影响采矿效率,同时增加充填压力,因此合理的采场结构参数对于保证矿山的安全高效生产至关重要。为此,该文借助厚板理论,分析顶板拉应力分布状态,对山后矿区深度在-282~-500 m的多个中分段典型采场进行优化设计,得到各采场的极限跨度值。该研究的应用将为矿山的安全防护和工程参数优化提供可靠数据,为矿山深部安全开采提供技术支撑。

以APOS理论为基础的高数极限概念教学实践分析

以高数极限概念教学实践为例,将APOS理论的内涵给予体现,提出优化极限概念教学的方法,分析学情及指导方向,深化高等数学极限概念教学,结合教学案例,提出优化策略,为提高学生对极限概念的深度理解、知识应用、重点掌握奠定基础。

民刑防卫限度一元论之再提倡--基于“行为导向的双层次判断模式”

民刑两大部门法对防卫限度的差异化规定为民刑防卫限度一元论与二元论之争埋下伏笔。民刑防卫限度二元论以缓和违法一元论为基底,存在无法调和的理论缺陷。从法律条文的角度分析,民法与刑法关于防卫限度的立法表述虽然有所不同,但并不足以推出“基本相适应说”与“必需说”之对立,认为民刑防卫限度的判断标准各成一派的观点没有规范依据。与民刑防卫限度二元论相比,民刑防卫限度一元论更加契合正当防卫的正当根据与制度目的,具有显著优势。民法一元论的两条演绎路径均面临着无法回应的质疑,应当予以摒弃。刑法一元论立场下的“行为导向的双层次判断模式”采用行为限度与结果限度相区分的体系构造,并以“必需说”为理论内核,能够有效地纠正“唯结果论”的错误理念,顺应了正当防卫权不断扩张的立法趋势。

爆破震动对西湾露天煤矿边坡稳定性的影响

爆破震动是影响边坡稳定性的重要因素之一,为了探究爆破产生的震动对西湾露天煤矿边坡稳定性的影响情况,采用数值模拟、极限平衡理论等研究方法与手段,通过爆破监测数据测拟合出爆破监测点处的震动加速度,对施加了不同数值的水平方向震动加速度的坡面进行稳定性模拟。结果表明:当水平方向的震动加速度从0上升到0.03时,其坡面的稳定系数下降0.19;当水平方向的震动加速度从0.03上升到0.05时,其坡面的稳定系数下降0.114;爆破震动对边坡稳定性的影响会随着爆破震动加速度的增大而逐渐降低。

5G通信中Polar码的编译码研究和应用

为了优化第五代通信技术的实现复杂度和信息传输速度,基于信道极化现象的Polar码逐渐受到了关注与研究,并产生了诸多行业标准以及研究成果。近年来,Polar码编译码技术的发展与优化促进了第五代通信技术的普及,而新一代通信技术的快速应用也推动了底层编译码技术的进一步更新。文中通过回顾Polar码编译码技术的研究历史,总结了第五代通信中相关技术的研究现状与脉络,在此基础上深入分析和讨论了当前编译码理论的问题与需求,提出了未来通信技术中底层编译码理论的研究趋势。