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综合管廊的区间设计 预览
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作者 强健 王恒栋 祁峰 《隧道建设(中英文)》 北大核心 2019年第9期1480-1485,共6页
为进一步完善城市地下综合管廊工程设计理论,提高综合管廊工程设计的科学性与合理性,基于大量综合管廊工程设计实践,提出将“区间”概念应用于综合管廊工程的总体设计。通过对综合管廊功能需求和入廊管线技术要求的分析,给出综合管廊各... 为进一步完善城市地下综合管廊工程设计理论,提高综合管廊工程设计的科学性与合理性,基于大量综合管廊工程设计实践,提出将“区间”概念应用于综合管廊工程的总体设计。通过对综合管廊功能需求和入廊管线技术要求的分析,给出综合管廊各类“功能区间”的定义、特征;通过进一步分析综合管廊各类功能区间的相互关系和重要性,提出通过功能区间构建具备复合功能属性、可复制的“单元区间”,再通过单元区间的复制串联实现综合管廊总体设计的系统布置方法。最后,提出以“单元区间”为核心理念的综合管廊“区间设计”的定义和一般方法,以期为综合管廊工程系统布置提供一种新的设计思路。 展开更多
关键词 综合管廊 区间 功能区间 单元区间 区间设计
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T形截面振子的驰振特性试验研究 预览
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作者 燕翔 练继建 +3 位作者 刘昉 任泉超 张军 邵楠 《振动工程学报》 EI CSCD 北大核心 2019年第3期431-438,共8页
T形振子的流致振动响应表现出了"非自限制"特性,随着流速的增大出现驰振现象,振动增强,有利于能量利用.但T形振子在复杂环境条件及自身截面变化条件下的研究尚未开展.基于此,进行了T形振子的试验研究,旨在探索其流致振动完整... T形振子的流致振动响应表现出了"非自限制"特性,随着流速的增大出现驰振现象,振动增强,有利于能量利用.但T形振子在复杂环境条件及自身截面变化条件下的研究尚未开展.基于此,进行了T形振子的试验研究,旨在探索其流致振动完整响应规律及在不同截面高宽比下的响应差异,具体结论如下:与三棱柱振子类似,T形振子也存在硬、软驰振现象,阻尼比较大时,出现硬驰振现象,而阻尼比较小时出现软驰振现象;软驰振响应中,振子的驰振具有自激发特性,由涡激振动激发而成;硬驰振响应中,振子需外力才可激发驰振;随着截面高宽比的增大,振动响应逐渐由硬驰振转化为软驰振,且驰振分支中振幅与频率均有所降低. 展开更多
关键词 流致振动 涡激振动 T形截面 驰振 截面高宽比
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Unit 1 What’s the m atter?Section B 2a—2e教学设计及评析 预览
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作者 孙黎 张丽华 《黑龙江教育:中学版》 2019年第5期18-21,共4页
[本课选自人教版义务教育课程标准实验教科书《英语》(新目标)八年级下册。]一、教材内容与分析本单元话题是健康与急救(Health and first aid).Section B是Section A主题的继续与延伸,由Section A侧重谈论疾病及不适转向对事故伤害、急... [本课选自人教版义务教育课程标准实验教科书《英语》(新目标)八年级下册。]一、教材内容与分析本单元话题是健康与急救(Health and first aid).Section B是Section A主题的继续与延伸,由Section A侧重谈论疾病及不适转向对事故伤害、急救(first aid)的讨论;语言上,巩固Section A所学重点语言内容、词汇及表达,突出对步骤顺序的表达;技能上,侧重综合性的听、读、写的训练,尤其突出阅读. 展开更多
关键词 SECTION 意志品质 优良品质 珍惜生命 s the M atter?Section B 2a UNIT 1 What 教学设计
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AutoCAD格式图件转换为MapGIS格式图件的方法 预览
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作者 张旭 《化工矿产地质》 CAS 2019年第1期46-49,共4页
AutoCAD格式图件保存为DXF的交换格式图件,利用section软件读取DXF文件,并分层保存,通过综合整饰,得到转换后未添加坐标系统的MapGIS格式图件,可利用MapGIS生成标准图框的方式,为转换后的图件添加坐标系统section和MapGIS两款软件配合使... AutoCAD格式图件保存为DXF的交换格式图件,利用section软件读取DXF文件,并分层保存,通过综合整饰,得到转换后未添加坐标系统的MapGIS格式图件,可利用MapGIS生成标准图框的方式,为转换后的图件添加坐标系统section和MapGIS两款软件配合使用,可将AutoCAD格式图件较好的、快速转换为MapGIS格式的图件。 展开更多
关键词 AUTOCAD MAPGIS SECTION 转换
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General explicit solutions of most economic sections and applications for trapezoidal and parabolic channels 预览
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作者 Yan-cheng Han Said MEasa Xue-ping Gao 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第5期1034-1042,共9页
A channel section that has minimum construction cost is known as the most economic section.Such a section has important implications for economic efficiency.However,the most economic section is a complex optimization ... A channel section that has minimum construction cost is known as the most economic section.Such a section has important implications for economic efficiency.However,the most economic section is a complex optimization model with nonlinear objective function and constraints that is difficult to use by ordinary engineers.A general simple formula for the most economic section has not been attempted.In this paper,the general differential equation for the most economic section is derived using Lagrange multiplier optimization method.A simple method to solve the most economic section is proposed that converted the optimization model into a general equation for the most economic section of any shape.By solving this equation,the dimensions of the most economic section are directly obtained.To illustrate,the direct formula for trapezoidal section is derived.To aid application in practice,a simple explicit iterative formula for trapezoidal sections is presented.The direct and explicit iterative formulas were validated.The proposed method is superior to the classical optimization method and as such represent a valuable tool for open channel design.To illustrate the versatility of the presented method,a direct formula for the parabolic section was also derived. 展开更多
关键词 Most economic section CHANNEL PARABOLIC EXPLICIT hydraulic section
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In-medium NN→NΔ cross section and its dependence on effective Lagrange parameters in isospin-asymmetric nuclear matter
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作者 崔莹 张英逊 李祝霞 《中国物理C:英文版》 SCIE CAS CSCD 2019年第2期115-124,共10页
The in-medium NN→N△ cross sections and its differential cross sections in isospin asymmetric nuclear medium are investigated in the framework of the one-boson exchange model by including isovector mesons, i.e., δan... The in-medium NN→N△ cross sections and its differential cross sections in isospin asymmetric nuclear medium are investigated in the framework of the one-boson exchange model by including isovector mesons, i.e., δand p mesons. Our results show that the in-medium NN→N△ cross sections are suppressed when the density increases, and the differential cross sections become isotropic with an increase in the density around the △ threshold energy. The isospin splitting on the medium correction factor, R =σNN→N△*/σNN→N△free is observed for different channels of NN→N△, especially around the threshold energy for all the effective Lagrangian parameters. By analyzing the selected effective Lagrangian parameters, our results show that the larger effective mass is, the weaker medium correction R is. 展开更多
关键词 in-medium NN→NΔcross SECTION isospin-asymmetric nuclear matter Lagrangian PARAMETERS differential CROSS SECTION
Section 在“矿山测绘”资源储量估算中的应用探讨 预览
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作者 刘川 《世界有色金属》 2019年第5期27-27,29共2页
“矿山测绘”能为测绘工程行业提供有效依据,结合矿山测量、采矿企业的技术标准等,可以为地下工程行业、隧道工程提供有效指导,促使其工作意义的发挥。对矿产资源储量进行估算,是“矿山测绘”以及整个测绘技术中最为关键的部分。尤其是... “矿山测绘”能为测绘工程行业提供有效依据,结合矿山测量、采矿企业的技术标准等,可以为地下工程行业、隧道工程提供有效指导,促使其工作意义的发挥。对矿产资源储量进行估算,是“矿山测绘”以及整个测绘技术中最为关键的部分。尤其是在现代科学技术水平逐渐提升下,Section成为矿产资源储量估算的主要手段。在本文中,具体探究Section在“矿山测绘”资源储量估算中的应用。 展开更多
关键词 SECTION “矿山测绘” 资源 储量 估算
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美國專利訴訟綜述及最新發展(下)
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作者 Thomas L Jarvis Cyrus T Frelinghuysen +2 位作者 Randall R Rader 郝元 王維多 《中国专利与商标》 2019年第3期74-87,共14页
五、侵權行爲的最終救濟針對侵權行爲有兩種救濟:損害賠償金和禁令救濟。1.損害賠償金專利法規定,'損害賠償金應就侵權行爲充分賠償,在任何情况下不得少於侵權方使用發明應支付的合理的使用費'。81法院已經認可了計算合適的賠... 五、侵權行爲的最終救濟針對侵權行爲有兩種救濟:損害賠償金和禁令救濟。1.損害賠償金專利法規定,'損害賠償金應就侵權行爲充分賠償,在任何情况下不得少於侵權方使用發明應支付的合理的使用費'。81法院已經認可了計算合適的賠償金的多個依據,其中利潤損失和合理的使用費是最常見的兩個依據。 展开更多
关键词 PRO SECTION
Non-adiabatic quantum dynamical studies of Na(3p) + HD(v = 1, j5) = 0)→NaH/NaD + D/H reaction
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作者 温月佩 布仁巴雅尔 陈茂笃 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第6期169-175,共7页
Non-adiabatic dynamical calculations are carried out for the Na(3 p)+HD(ν = 1, j = 0)→NaH/NaD+D/H reaction on the diabatic potential energy surfaces of Wang et al.(Sci. Rep. 2018, 8, 17960) by using the time-depende... Non-adiabatic dynamical calculations are carried out for the Na(3 p)+HD(ν = 1, j = 0)→NaH/NaD+D/H reaction on the diabatic potential energy surfaces of Wang et al.(Sci. Rep. 2018, 8, 17960) by using the time-dependent wave packet method. The state-to-state integral cross sections and differential cross sections of two reaction channels(NaH/NaD+D/H)are calculated for collision energy up to 0.4 eV. The cross section branching ratio indicates that the dominant reaction channel changes from NaD+H to NaH+D when the collision energy is larger than 0.227 eV. The products from two reaction channels both prefer to form in vibrationally cold but rotationally hot states, and they both tend to forward scattering. 展开更多
关键词 TIME-DEPENDENT wave packet method NON-ADIABATIC REACTION integral CROSS SECTION differential CROSS SECTION
Unit 7 Will people have robots?Section B 2a-2e教学设计及评析 预览
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作者 孙黎 《黑龙江教育:中学版》 2019年第9期14-16,共3页
[本课选自人教版义务教育课程标准实验教科书《英语》(新目标)八年级上册。]一、教材内容分析本单元的话题主要是谈论未来生活(Life in the future),本节Section B部分的阅读课将Section A部分'谈论未来世界'的话题拓展到'... [本课选自人教版义务教育课程标准实验教科书《英语》(新目标)八年级上册。]一、教材内容分析本单元的话题主要是谈论未来生活(Life in the future),本节Section B部分的阅读课将Section A部分'谈论未来世界'的话题拓展到'谈论个人的未来生活'。2a-2e是一个整体的阅读板块,该单元阅读语篇谈论的是对未来机器人发展的不同预测。 展开更多
关键词 snake SECTION UNIT 7 WILL PEOPLE HAVE robots?Section B 2a-2e 教学设计
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Experimental Investigation of the Mg–Zn–Zr Isothermal Section at 400℃
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作者 Yong-Peng Liang Shu-Hong Liu +1 位作者 Kai Xu Yong Du 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第4期426-432,共7页
Mg-Zn-Zr series Mg alloys(ZK) are one of the most important commercial Mg alloys due to their good comprehensive mechanical properties. The phase equilibria of the Mg-Zn-Zr system at 400℃ covering the overall composi... Mg-Zn-Zr series Mg alloys(ZK) are one of the most important commercial Mg alloys due to their good comprehensive mechanical properties. The phase equilibria of the Mg-Zn-Zr system at 400℃ covering the overall composition range were investigated by X-ray diffraction and electron probe microanalyses on thirteen ternary alloys. Three ternary compounds,τ1,τ2 and τ3, were detected to be thermodynamically stable at 400 ℃, and their homogeneity range was determined to be Mg(7-17)Zn(80-88)Zr(4-6), Mg(15-22)Zn(66-65)Zr(9-16) and Mg9 Zn68Zr23(in at.%), respectively. Eight three-phase regions and four two-phase regions were observed. The maximum solubility of Mg in Zn22 Zr, Zn39 Zr5 and Zn3 Zr phases was measured to be 0.52, 0.37 and 0.99 at.%, respectively, while the solubility of Zr in MgZn2 and Mg2 Zn3 phases is negligible. The isothermal section of the Mg-Zn-Zr system at 400 ℃ was then constructed based on the present experimental data. 展开更多
关键词 Mg–Zn–Zr ISOTHERMAL section Phase EQUILIBRIA TERNARY compounds
Neuraxial adjuvants for prevention of perioperative shivering during cesarean section:A network meta-analysis following the PRISMA guidelines 预览
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作者 Yi-Wei Zhang Juan Zhang +5 位作者 Jia-Qi Hu Chun-Lei Wen Shu-Yang Dai Dan-Feng Yang Li-Fang Li Qi-Biao Wu 《世界临床病例杂志》 2019年第16期2287-2301,共15页
BACKGROUND Perioperative shivering is clinically common during cesarean sections under neuraxial anesthesia,and several neuraxial adjuvants are reported to have preventive effects on it.However,the results of current ... BACKGROUND Perioperative shivering is clinically common during cesarean sections under neuraxial anesthesia,and several neuraxial adjuvants are reported to have preventive effects on it.However,the results of current studies are controversial and the effects of these neuraxial adjuvants remain unclear.AIM To evaluate the effects of neuraxial adjuvants on perioperative shivering during cesarean sections,thus providing an optimal choice for clinical application.METHODS A systematic review and network meta-analysis were conducted following the PRISMA (Preferred Reported Items for Systematic Review and Meta-analysis) guidelines.Analyses were performed using Review Manager 5.3 and Stata 14.0.We searched PubMed,EMBASE,Web of Science,and Cochrane Central databases for eligible clinical trials assessing the effects of neuraxial adjuvants on perioperative shivering and other adverse events during cesarean sections.Perioperative shivering was defined as the primary endpoint,and nausea,vomiting,pruritus,hypotension,and bradycardia were the secondary outcomes.RESULTS Twenty-six studies using 9 neuraxial adjuvants for obstetric anesthesia during caesarean sections were included.The results showed that,compared with placebo,pethidine,fentanyl,dexmedetomidine,and sufentanil significantly reduced the incidence of perioperative shivering.Among the four neuraxial adjuvants,pethidine was the most effective one for shivering prevention (OR = 0.15,95%CI: 0.07-0.35,surface under the cumulative ranking curve 83.9),but with a high incidence of nausea (OR = 3.15,95%CI: 1.04-9.57) and vomiting (OR = 3.71,95%CI: 1.81-7.58).The efficacy of fentanyl for shivering prevention was slightly inferior to pethidine (OR = 0.20,95%CI: 0.09-0.43),however,it significantly decreased the incidence of nausea (OR = 0.34,95%CI: 0.15-0.79) and vomiting (OR = 0.25,95%CI: 0.11-0.56).In addition,compared with sufentanil,fentanyl showed no impact on haemodynamic stability and the incidence of pruritus.CONCLUSION Pethidine,fentanyl,dexmedetomidine,and sufentanil 展开更多
关键词 Neuraxial ADJUVANTS SHIVERING CESAREAN section PREVENTION Network metaanalysis
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淠史杭灌区水资源配置与调度实践 预览 被引量:1
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作者 朱红 《中国水利》 2019年第3期16-18,共3页
安徽省淠史杭灌区自建成运行以来,建立形成了一套符合灌区水资源特点、以“统一调度、计划供水、总量控制、综合利用”为主要特征的水资源配置与供水调度体系,取得了明显的灌溉供水和抗旱减灾效益,为区域经济社会发展、灌区粮食稳产、... 安徽省淠史杭灌区自建成运行以来,建立形成了一套符合灌区水资源特点、以“统一调度、计划供水、总量控制、综合利用”为主要特征的水资源配置与供水调度体系,取得了明显的灌溉供水和抗旱减灾效益,为区域经济社会发展、灌区粮食稳产、城镇居民生活、生态环境改善等提供了安全可靠的水资源保障。 展开更多
关键词 淠史杭灌区 水资源配置 供水调度 成效
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空间操作笔记 剖面设计中的三种预设性策略 预览
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作者 孔宇航 王雪睿 《时代建筑》 2019年第5期162-169,共8页
文章以剖面为切入点探析空间操作问题,首先回顾剖面的历史演变,继而以欧氏几何的空间求解、层叠空间的动态性操作、复杂性空间的有机构建三种方式阐释剖面设计中的预设性策略。通过历史梳理、剖面分析与案例解构,论证剖面与空间操作的... 文章以剖面为切入点探析空间操作问题,首先回顾剖面的历史演变,继而以欧氏几何的空间求解、层叠空间的动态性操作、复杂性空间的有机构建三种方式阐释剖面设计中的预设性策略。通过历史梳理、剖面分析与案例解构,论证剖面与空间操作的内在关联性。 展开更多
关键词 剖面 空间操作 预设 设计策略
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大跨径变截面现浇梁施工工艺--基于钢管桩贝雷梁+满堂碗扣叠合型支架 预览
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作者 娄晶凯 《工程建设与设计》 2019年第2期120-121,共2页
我国当前桥梁工程施工技术应用中,对于梁体浇筑技术施工的研究出现了新的发展趋势,采用叠合支架施工浇筑已经成为梁体施工技术转变发展的必然趋势。论文通过工程实例,介绍叠合支架的施工设计和梁体施工工艺,为相关工程提供参考。
关键词 大跨径 截面 现浇梁施工 钢管桩 叠合支架
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The density-and isospin-dependent ?-formation cross section and its decay width
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作者 QingFeng Li ZhuXia Li 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第7期76-81,共6页
The energy-, density-, and isospin-dependent ?-formation cross section σNπ→?* and ?-decay width are calculated based on the relativistic BUU approach in which the effective mass splitting of nucleon and ? baryons i... The energy-, density-, and isospin-dependent ?-formation cross section σNπ→?* and ?-decay width are calculated based on the relativistic BUU approach in which the effective mass splitting of nucleon and ? baryons in isospin-asymmetric matter is considered by the inclusion of the δ meson exchange in the effective Lagrangian density and the density-dependent coupling constants of Hofmann et al. The results show that the σNπ→?* is decreased(increased) moderately with increasing density with(without)the consideration of medium modifications on pion mass. Meanwhile, if the invariant mass of the system is not far from the ?pole mass, the ?-decay width is also weakly dependent on density. The mass splitting effect of differently charged nucleon and ?baryons on σNπ→?* is found to be more obvious than that of pion mesons but much weaker than the mass splitting in the hard ?production channel NN → N?. Further, the largest mass-splitting influence is seen in the π-p → ?0 and π+n → ?+ channels but not in the production of ?- and ?++ isobars. 展开更多
关键词 ?-formation CROSS section DECAY WIDTH SYMMETRY energy
A scaling phenomenon for the cross section of fragment produced in projectile fragmentation reactions
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作者 Yi-Dan Song Hui-Ling Wei Chun-Wang Ma 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第9期60-69,共10页
A scaling phenomenon has been found for the cross section of a fragment, which is defined as a "square" cross section(SCS).This phenomenon can unify the cross sections of fragments in projectile fragmentatio... A scaling phenomenon has been found for the cross section of a fragment, which is defined as a "square" cross section(SCS).This phenomenon can unify the cross sections of fragments in projectile fragmentation(PF) reactions. An empirical formula is proposed to calculate SCSfor a fragment with parameters determined by an extensive investigation of measured reactions ranging from Fermi energies to relativistic energies. The scaling phenomenon of SCShas been verified using different techniques,showing that the scaling of SCSgenerally exists in PF reactions. The concept of SCS, which can be assumed as a standard value for a fragment, is shown to accurately predict the cross sections of isotopes in PF reactions with incident energies ranging from tens of A MeV to approximately 1000 A MeV. 展开更多
关键词 SCALING phenomenon cross section prediction intermediate mass FRAGMENTS PROJECTILE FRAGMENTATION
综采工作面区段煤柱合理宽度研究 预览
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作者 杨保国 《山东煤炭科技》 2019年第1期43-45,共3页
通过对西曲矿2^#综采工作面区段煤柱合理宽度的留设理论分析,根据煤柱保持稳定的基本条件对工作面煤柱合理宽度进行了理论计算,应用FLAC^3D软件对其进行了模拟计算。结果表明:理论计算结果与模拟结果相吻合,为类似区段煤柱合理留设提供... 通过对西曲矿2^#综采工作面区段煤柱合理宽度的留设理论分析,根据煤柱保持稳定的基本条件对工作面煤柱合理宽度进行了理论计算,应用FLAC^3D软件对其进行了模拟计算。结果表明:理论计算结果与模拟结果相吻合,为类似区段煤柱合理留设提供依据。 展开更多
关键词 区段 煤柱 宽度 模拟
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Experimental investigation on the failure mechanism of a rock landslide controlled by a steep-gentle discontinuity pair
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作者 HUANG Da ZHONG Zhu GU Dong-ming 《山地科学学报:英文版》 SCIE CSCD 2019年第6期1258-1274,共17页
A type of rock landslide is very common in practical engineering, whose stability is mainly controlled by the rock bridge between the steep tensile crack at the crest and the low-inclination weak discontinuities at th... A type of rock landslide is very common in practical engineering, whose stability is mainly controlled by the rock bridge between the steep tensile crack at the crest and the low-inclination weak discontinuities at the toe(namely, ligament is the term for the locking section in the slope). To obtain a deeper understanding into the failure process of this kind of landslide, twenty-four physical slope models containing a steep-gentle discontinuity pair(a steep crack in the upper part and a low-inclination discontinuity in the lower part) were tested by applying vertical loads at the crests. The results indicate that the inclination angle of the ligament(θ) has great influence on the failure and stability of this type of rock slope. With the change of θ, three failure patterns(five subtypes) concerning the tested slopes can be observed, i.e., tensile failure of the ligament(Type 1), tension-shear failure of the ligament(Type 2) and two-stage failure of the main body(Type 3). The failure process of each failure mode presents five stages in terms of crack development, vertical load, horizontal/vertical displacements and strains in the ligaments. The specific range of the ligament angle between different failure patterns is summarized. The discussion on the failure resistances and ductility of different failure patterns, and the guiding significances of the experimental findings to the stability evaluation and the reinforcement were conducted. 展开更多
关键词 Rock LANDSLIDE FAILURE pattern FAILURE evolution Locking section Crack COALESCENCE
大采高工作面区段合理煤柱宽度研究 预览
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作者 张海荣 索永录 《山东煤炭科技》 2019年第9期31-33,36共4页
为了保证煤矿安全生产,提高煤炭资源回采率,在分析陕西北部矿区金鸡滩煤矿大采高工作面生产技术条件的基础上,实测当前留设区段煤柱的侧向支承压力,分析其留设尺寸的合理性,采用多种理论计算出煤柱尺寸,综合取值后做现场验证。研究结果... 为了保证煤矿安全生产,提高煤炭资源回采率,在分析陕西北部矿区金鸡滩煤矿大采高工作面生产技术条件的基础上,实测当前留设区段煤柱的侧向支承压力,分析其留设尺寸的合理性,采用多种理论计算出煤柱尺寸,综合取值后做现场验证。研究结果表明:受两次采动影响后,原留设煤柱呈超稳定状态,宽度偏大,按25m留设煤柱即可满足生产需要。 展开更多
关键词 大采高 综采 区段 煤柱
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