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Characteristics of grain size distribution and the shear strength analysis of Chenjiaba long runout coseismic landslide

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Journal of Mountain Science 2019年第9期16卷 2110-2125页

作者： GETAHUN Ephrem QI Sheng-wen GUO Song-feng ZOU Yu LIANG Ning Key Laboratory of Shale Gas and Geoengineering Institute of Geology and Geophysics Chinese Academy of Sciences Chaoyang District Beijing 100029 China Institute of Earth Science Chinese Academy of Sciences Beijing 100029 China University of Chinese Academy of Sciences Beijing 100049 China Arba Minch University Department of Geology P. O. Box 21 Arba Minch 00251 Ethiopia

Study on the grain size distribution characteristics and the frictional strength behavior of the slide deposits are helpful to disclose the landslide runout process and understand the mechanism of a long runout landslide. We performed grain size distribution analysis on samples collected from Chenjiaba landslide induced by Wenchuan earthquake. The grain size distribution of samples from the landslide sections quantitatively depicts a gradual coarsening upward grading from shear zone to the top section. Then a multistage-multiphase ring shearing approach was used to determine a comparative shear strength behavior of samples from each landslide section. In this method, a sample was sheared continuously for large displacement and fast rate on different normal stress conditions. The multiphase shear mode with a maximum of 105 mm/min rate has allowed observing the qualitative change and patterns of the frictional resistance behaviors of soils under different normal stresses. The results of coefficient of friction values under multiphase shear mode have shown substantial post peak shear weakening behaviors after large shear displacement that can be narrated with long runout processes. The shear strength test results indicate that the shear zone samples have developed higher friction angle values compared to overlying section samples, on the last phase of shear process, which may be very important to understand the braking mechanism of a long runout landslide.

关键词： Grain size distribution Long runout Landslide Multistage-Multiphase Ring Shear

基于离散元runout预测的张家湾滑坡风险评估

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地质灾害与环境保护 2024年第1期35卷 1-6页

作者：董阳丹魏占玺董建辉成都理工大学地质灾害防治与地质环境保护国家重点实验室成都610059 青海省环境地质重点实验室西宁810007 青海省地质环境保护与灾害防治工程技术研究中心西宁810007 四川省非饱和土力学特性及工程技术省高校工程研究中心成都610106 成都大学建筑与土木工程学院成都610106

滑坡是我国最重要的地质灾害之一,其每年造成大量的人员伤亡和财产损失,故滑坡风险评估对防治滑坡灾害、降低社会经济损失具有重要意义。基于现场野外调查,利用离散元软件UDEC对西宁市张家湾滑坡进行runout预测分析,结合动力分析与条件... 详细信息

滑坡是我国最重要的地质灾害之一,其每年造成大量的人员伤亡和财产损失,故滑坡风险评估对防治滑坡灾害、降低社会经济损失具有重要意义。基于现场野外调查,利用离散元软件UDEC对西宁市张家湾滑坡进行runout预测分析,结合动力分析与条件分析法对张家湾滑坡进行风险评估。结果表明:张家湾滑坡在天然工况下为稳定状态,在暴雨工况下为欠稳定状态,其最远移距为55m,最大影响范围为1.106×105 m2;张家湾滑坡在暴雨工况下的失稳概率为0.459;张家湾滑坡一旦在暴雨情况下发生失稳,人员伤亡风险值为46人,根据滑坡灾害社会接受水平曲线判定其属于不可接受范围;经济损失风险值为5180.88万元。根据经济损失风险等级进行判断其属于第5等级。

关键词：张家湾滑坡风险评估离散元 runout

Precision micro-milling process:state of the art

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Advances in Manufacturing 2021年第2期9卷 173-205页

作者： Lorcan O’Toole Cheng-Wei Kang Feng-Zhou Fang Center of Micro/Nano Manufacturing Technology(MNMT-Dublin) University College DublinDublin 4Ireland State Key Laboratory of Precision Measuring Technology and Instruments Center of Micro/Nano Manufacturing Technology(MNMT)Tianjin UniversityTianjin 300072People’s Republic of China

Micro-milling is a precision manufacturing process with broad applications across the biomedical,electronics,aerospace,and aeronautical industries owing to its versatility,capability,economy,and efficiency in a wide range of *** particular,the micro-milling process is highly suitable for very precise and accurate machining of mold prototypes with high aspect ratios in the microdomain,as well as for rapid micro-texturing and micro-patterning,which will have great importance in the near future in bio-implant *** is particularly true for machining of typical difficult-to-machine materials commonly found in both the mold and orthopedic implant ***,inherent physical process constraints of machining arise as macromilling is scaled down to the *** leads to some physical phenomena during micromilling such as chip formation,size effect,and process *** dynamic physical process phenomena are introduced and discussed in *** is important to remember that these phenomena have multifactor effects during micro-milling,which must be taken into consideration to maximize the performance of the *** most recent research on the micro-milling process inputs is discussed in detail from a process output perspective to determine how the process as a whole can be ***,newly developed processes that combine conventional micro-milling with other technologies,which have great prospects in reducing the issues related to the physical process phenomena,are also ***,the major applications of this versatile precision machining process are discussed with important insights into how the application range may be further broadened.

关键词： Precision machining Micro-milling Size effect Deflection runout Tool wear

A review of chatter vibration research in milling

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Chinese Journal of Aeronautics 2019年第2期32卷 215-242页

作者： Caixu YUE Haining GAO Xianli LIU Steven Y.LIANG Lihui WANG Harbin University of Science and Technology Georgia Institute of Technology KTH Royal Institute of Technology

Chatter is a self-excited vibration of parts in machining systems. It is widely present across a range of cutting processes, and has an impact upon both efficiency and quality in production processing. A great deal of research has been dedicated to the development of technologies that are able to predict and detect chatter. The purpose of these technologies is to facilitate the avoidance of chatter during cutting processes, which leads to better surface precision, higher productivity,and longer tool life. This paper summarizes the current state of the art in research regarding the problems of how to arrive at stable chatter prediction, chatter identification, and chatter control/-suppression, with a focus on milling processes. Particular focus is placed on the theoretical relationship between cutting chatter and process damping, tool runout, and gyroscopic effect, as well as the importance of this for chatter prediction. The paper concludes with some reflections regarding possible directions for future research in this field.

关键词： Chatter Gyroscopic effects Milling Process damping Tool runout

New Cutting Force Modeling Approach for Flat End Mill

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Chinese Journal of Aeronautics 2007年第3期20卷 282-288页

作者： WAN Min ZHANG Wei-hong TAN Gang QIN Guo-hua Sino-French Laboratory of Concurrent Engineering The Key Laboratory of Contemporary Design ＆ Integrated Manufacturing Technology Northwestern Polytechnical University Xi＇an 710072 China

A new mechanistic cutting force model for flat end milling using the instantaneous cutting force coefficients is proposed. An in-depth analysis shows that the total cutting forces can be separated into two terms: a nominal component independent of the runout and a perturbation component induced by the runout. The instantaneous value of the nominal component is used to calibrate the cutting force coefficients. With the help of the perturbation component and the cutting force coefficients obtained above, the cutter runout is identified. Based on simulation and experimental results, the validity of the identification approach is demonstrated. The advantage of the proposed method lies in that the calibration performed with data of one cutting test under a specific regime can be applied for a great range of cutting conditions.

关键词： runout cutting force flat end mill calibration cutting force coefficient

GIS tools for preliminary debris-flow assessment at regional scale

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Journal of Mountain Science 2017年第12期14卷 2498-2510页

作者： cavalli marco crema stefano trevisani sebastiano marchi lorenzo consiglio nazionale delle ricerche istituto di ricerca per la protezione idrogeologicaCorso Stati Uniti 435127 PadovaItaly universitàdi padova dipartimento territorio e sistemi agro-forestaliVia dell’Universita 1635020 Legnaro(PD)Italy universitàiuav di venezia dipartimento di architettura costruzione conservazioneDorsoduro 220630123 VeneziaItaly

The assessment of the areas endangered by debris flows is a major issue in the context of mountain watershed management. Depending on the scale of analysis, different methods are required for the assessment of the areas exposed to debris *** 2-D numerical models are advised for detailed mapping of inundation areas on individual alluvial fans, preliminary recognition of hazard areas at the regional scale can be adequately performed by less data-demanding methods, which enable priority ranking of channels and alluvial fans at risk by debris flows. This contribution focuses on a simple and fast procedure that has been implemented for regionalscale identification of debris-flow prone channels and prioritization of the related alluvial fans. The methodology is based on the analysis of morphometric parameters derived from Digital Elevation Models(DEMs). Potential initiation sites of debris flows are identified as the DEM cells that exceed a threshold of slope-dependent contributing area. Channel reaches corresponding to debris flows propagation, deceleration and stopping conditions are derived from thresholds of local slope. An analysis of longitudinal profiles is used for the computation of the runout distance of debris flows. Information on erosion-resistant bedrock channels and sediment availability surveyed in the field are taken into account in the applications. A set of software tools was developed and made available(https://***/Hydrogeomorphology Tools) to facilitate the application of the procedure. This approach, which has been extensively validated by means of field checks, has been extensively applied in the eastern Italian Alps. This contribution discusses potential and limitations of the method in the frame of the management of small mountain watersheds.

关键词： Debris flow Geographic information system Digital elevation models runout Alluvial fan Watershed management Geomorphometry

Progressive fragmentation of granular assemblies within rockslides: Insights from discrete-continuous numerical modeling

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Journal of Mountain Science 2024年第4期21卷 1174-1189页

作者： JIANG Hui ZHOU Yuande WANG Jinting DU Xiuli HUANG Hailong Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100124China. Key Laboratory of the Hydrosphere Sciences of the Ministry of Water Resources Tsinghua UniversityBeijing 100084China China Three Gorges Construction Management Co. Ltd.Chengdu 610000China

Rock fragmentation plays a critical role in rock avalanches,yet conventional approaches such as classical granular flow models or the bonded particle model have limitations in accurately characterizing the progressive disintegration and kinematics of multi-deformable rock blocks during *** present study proposes a discrete-continuous numerical model,based on a cohesive zone model,to explicitly incorporate the progressive fragmentation and intricate interparticle interactions inherent in *** rock granular assemblies are released along an inclined plane and flow onto a horizontal *** numerical scenarios are established to incorporate variations in slope angle,initial height,friction coefficient,and particle *** evolutions of fragmentation,kinematic,runout and depositional characteristics are quantitatively analyzed and compared with experimental and field data.A positive linear relationship between the equivalent friction coefficient and the apparent friction coefficient is *** general,the granular mass predominantly exhibits characteristics of a dense granular flow,with the Savage number exhibiting a decreasing trend as the volume of mass *** process of particle breakage gradually occurs in a bottom-up manner,leading to a significant increase in the angular velocities of the rock blocks with increasing *** simulation results reproduce the field observations of inverse grading and source stratigraphy preservation in the *** propose a disintegration index that incorporates factors such as drop height,rock mass volume,and rock *** findings demonstrate a consistent linear relationship between this index and the fragmentation degree in all tested scenarios.

关键词： Rock fragmentation Rockslide Numerical modelling Discrete-continuous modelling runout Cohesive zone model

磁悬浮刚性转子系统振动机理分析与动力学建模

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控制理论与应用 2014年第12期31卷 1707-1713页

作者：房建成张会娟刘虎北京航空航天大学仪器科学与光电工程学院北京100191 北京航空航天大学新型惯性仪表与导航系统技术国防重点学科实验室北京100191

磁悬浮惯性执行机构采用磁轴承支承,可通过主动控制实现极微振动,但磁悬浮惯性执行机构仍存在频谱分量丰富的振动.首先在转子动静不平衡和Sensor runout振动机理分析的基础上,重点分析了Magnet runout产生振动机理;然后,建立包含多振动... 详细信息

磁悬浮惯性执行机构采用磁轴承支承,可通过主动控制实现极微振动,但磁悬浮惯性执行机构仍存在频谱分量丰富的振动.首先在转子动静不平衡和Sensor runout振动机理分析的基础上,重点分析了Magnet runout产生振动机理;然后,建立包含多振动源的系统动力学建模,并将整个动力学模型分解为平动和转动子系统,分析表明转子动静不平衡、Sensor runout和Magnet runout是通过不同的途径产生振动,不仅产生同频振动还包含倍频振动;最后,提出磁悬浮刚性转子系统主动振动控制的要求,为以后的主动振动控制研究奠定基础.

关键词：磁悬浮刚性转子主动振动控制转子不平衡磁中心偏心 Sensor runout

基于RS和GIS技术对区域滑坡进行高效快速敏感性评价的模型研究 ——以北川县为例

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基于RS和GIS技术对区域滑坡进行高效快速敏感性评价的模型研究 ...

作者：尹志华成都理工大学

学位级别：硕士

“5?12”汶川大地震导致高烈度区泥石流源地的滑坡更加发育,积累的松散物质更加丰富,同年北川“9?24”暴雨使泥石流源地滑坡进一步复活并产生大量新滑坡,从而使强震区泥石流发生频率增高,规模增大。近年来,地质灾害频繁发生,灾害给人类... 详细信息

“5?12”汶川大地震导致高烈度区泥石流源地的滑坡更加发育,积累的松散物质更加丰富,同年北川“9?24”暴雨使泥石流源地滑坡进一步复活并产生大量新滑坡,从而使强震区泥石流发生频率增高,规模增大。近年来,地质灾害频繁发生,灾害给人类的生命与物质财产带来的损失是巨大的,所以对滑坡、崩塌、泥石流等地质灾害的预测预警、防灾减灾势在必行。地理信息系统（GIS）技术、遥感（RS）技术的迅速发展为区域滑坡、泥石流灾害敏感性评价提供了很好的技术支持。本文研究将以GIS和RS技术为依托,以研究区高精度DEM数据和历史滑坡分布数据为基础资料,旨在实现对大范围滑坡进行快速、有效、低成本、高精度的敏感性评价,从而对灾害防治和滑坡避害范围提供决策依据。由于各种地质因素本身的不确定性,地质因素之间相互作用的复杂性,以及基础资料的质量问题与不完备,这些一直是困扰地质灾害区域预测预报的一道难题。本文将借鉴前人的研究,针对现有区域滑坡敏感性评价模型的优势和不足,提出一种改进模型。该模型将斜坡稳定性信息量评价模型与runout区基于DEM的水文分析模型进行有效的集成。斜坡稳定性评价模型是基于信息量统计模型对潜在滑坡源区的敏感性给予等级区划,其中对斜坡稳定性具有贡献的地形因子将会作为斜坡变形失稳的评测因子;基于DEM的水文分析模型主要是针对暴雨过程形成的斜坡表层径流导致悬挂于斜坡上的滑坡体表面和前缘松散物质向下输移进入沟道后转为泥石流的runout行为的敏感性等级区划。二者得出的敏感性等级区划专题图再次根据等级进行叠加分析,从而得出最终的综合评价结果。

关键词：斜坡稳定性 runout 遥感地理信息系统敏感性评价