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Earth Pressure of the Trapdoor Problem Using Three-Dimensional Discrete Element Method

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Computer Modeling in Engineering & Sciences 2023年第5期135卷 1503-1520页

作者： qizhi chen ChuliXu Baoping Zou Zhanyou Luo Changjie Xu Xu Long School of Civil Engineering and Architecture Zhejiang University of Science and TechnologyHangzhou310023China School of Civil and Environmental Engineering Ningbo UniversityNingbo315211China School of Civil Engineering and Architecture East China Jiaotong UniversityNanchang330013China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China

Load transformation from the yielding part of the soil to the adjacent part is known as the soil arching effect,which plays an important role in the design of various geotechnical ***’s trapdoor test was an importantmilestone in the development of theories on soil *** research on earth pressure of the trapdoor problem is presented in this paper using the three-dimensional(3D)discrete element method(DEM).Five 3D trapdoor models with different heights are established by 3DDEMsoftware PFC *** variation of earth pressure on the trapdoor with the downward movement of the trapdoor,the distribution of vertical earth pressure along the horizontal direction,the distribution of vertical earth pressure along the vertical direction,the distribution of lateral earth pressure coefficient along the depth direction,the magnitude and direction of contact force chain are studied,*** research results show that the earth pressure on the trapdoor decreases rapidly after the downward movement of the trapdoor,and then reaches the minimum earth *** that,the earth’s pressure will rise slightly,and whether this phenomenon occurs depends on the depth *** the bottom soil,due to the stress transfer caused by the soil arching effect,the ratio of earth pressure in the loose area decreases,while the ratio of earth pressure in the stable area *** the trapdoor moving down,the vertical earth pressure along the depth in the stable zone is basically consistent with the initial state,which shows an approximate linear *** the trapdoor moves down,the distribution of earth pressure along with the depth in the loose area changes,which is far less than the theoretical value of vertical earth pressure of its *** of the compression of the soil on both sides,the lateral earth pressure coefficient of most areas on the central axis of the loose zone is close to the passive earth pressure coefficient ***

关键词： Soil arching effect three dimensional discrete element earth pressure contact force chain

Numerical simulation of temporal and spatial evolution of fold-thrust belts in the northern and northeastern margins of the Qinghai-Tibetan Plateau

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Earthquake Research Advances 2021年第S1期1卷 23-25页

作者： qizhi chen Caibo Hu School of Earth and Planetary Sciences University of Chinese Academy of SciencesKey Laboratory of Computational GeodynamicsChinese Academy of SciencesBeijingChina

Fold-thrust belts are common structural styles under the background of long-term regional tectonic *** northern and northeastern margins of the Qinghai-Tibetan Plateau are located on the edge of the growth and expansion of the Qinghai-Tibetan *** nearly 10 Ma,some significant and typical fold thrust belt have been *** spatial-temporal evolution of these fold-thrust belts and the characteristics of surface deformations are significant issues in *** this paper,we use the elastoplastic finite element model with considering the contact nonlinearity to study the spatialtemporal evolution of the fold-thrust belts in the northern and northeastern margins of the Qinghai-Tibetan Plateau,with particular attention to the details of the relationship between the depth and the shallow,the spatialtemporal order,and the characteristics of the surface deformation,etc.,in order to make a relatively complete mechanical interpretation of the spatial-temporal evolution of the foldthrust belts in the northern and northeastern margins of the Qinghai-Tibetan Plateau from the perspective of geodynamics.

关键词： Fold-thrust belts Finite element model Elastoplasticity Northeastern margin of the Qinghai-Tibetan Plateau Frictonal contact

INTELLIGENT DECISION ALGORITHM FOR FAULT DETECTION AND ITS APPLICATION

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国防科技大学学报 1995年第3期17卷 33-40页

作者： Wu Jianjun Zhang Yulin chen qizhi(Department of Aerospace Technology, NUDT,Changsha, 410073 )

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ＩＮＴＥＬＬＩＧＥＮＴＤＥＣＩＳＩＯＮＡＬＧＯＲＩＴＨＭＦＯＲＦＡＵＬＴＤＥＴＥＣＴＩＯＮＡＮＤＩＴＳＡＰＰＬＩＣＡＴＩＯＮＷｕＪｉａｎｊｕｎ；ＺｈａｎｇＹｕｌｉｎ；ＣｈｅｎＱｉｚｈｉ（ＤｅｐａｒｔｍｅｎｔｏｆＡｅｒｏｓｐａｃｅＴｅｃｈｎｏｌｏｇｙ，...

关键词：故障检测智能决策算法

Fact-condition statements and super relation extraction for geothermic knowledge graphs construction

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Geoscience Frontiers 2023年第5期14卷 384-395页

作者： qizhi chen Hong Yao Shengwen Li Xinchuan Li Xiaojun Kang Wenwen Lai Jian Kuang School of Computer Science China University of GeosciencesWuhan 430074China State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan 430074China School of Geography and Information Engineering China University of GeosciencesWuhan 430074China

Researchers utilize information from the geoscience literature to deduce the regional or global geological *** this process has relied on the labor of *** the number of papers continues to increase,acquiring domain-specific knowledge becomes a heavy *** Graph(KG)is proposed as a new knowledge representation technology to change this ***,the super relation is not considered in the previous KG,which bridges the geological phenomenon(fact)and its precondition(condition).For instance,in the statement(“the late Archean was a crucial transition period in the history of global geodynamics”),the condition statement(“crucial transition for global geodynamics”)works as the complementary fact statement(“the late Archean was a crucial transition period”),which defines the scale of crucial transition accurately in the late *** this study,fact-condition statement extraction is introduced to construct a geological knowledge graph.A rule-based multi-input multi-output model(R-MIMO)is proposed for information *** the R-MIMO,fact-condition statements and their super relation are considered and extracted for the first *** verify its performances,a GeothCF dataset with 1455 fact tuples and 789 condition tuples is *** experiments,the R-MIMO model achieves the best performance by using BERT as encoder and LSTM-d as decoder,achieving F180.24%in tuple extraction and F170.03%in tag prediction ***,the geothermic KG with super relation is automatically constructed for the first time by trained R-MIMO,which can provide structured data for further geothermic research.

关键词： Fact-condition statements Super relation Knowledge graph Rule-based multi-input multi-output model

TEM Study of Microcrack Nucleation and Propagation for 310 Stainless Steel

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International Journal of Minerals,Metallurgy and Materials 1998年第2期12卷 100-103页

作者： Hongqi Li qizhi chen Yizhong Huang Yanbin Wang Wuyang Chu Applied Science School, UST Beijing, Beijing 100083, China Applied Science School UST Beijing Beijing 100083 China

TEM in situ tensile tests of 310 stainless steel show that a dislocation free zone (DFZ) forms if the displacement keeps constant after dislocations are emitted from a crack tip. The elastic DFZ is gradually thinned and the stress in the DFZ will reach the cohesive strength, resulting in nucleation of nanocracks in it and their bluntness into voids. If continuously tensioning, the inhomogeneously thinning ahead of the crack tip, initiating and connecting of microcracks or microvoids will be observed rather than a DFZ, nanocracks' initiation and bluntness into voids. The inverse pile-up ahead of a loaded crack tip can move back to the crack tip when unloading.

关键词： 310 stainless steel in situ TEM tension dislocation free zone initiation of nanocrack

Influence of adjacent shield tunneling construction on existing tunnel settlement: field monitoring and intelligent prediction

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第12期24卷 1106-1119页

作者： Long RAN Yang DING qizhi chen Baoping ZOU Xiaowei YE School of Civil Engineering and Architecture Zhejiang University of Science&TechnologyHangzhou 310023China Zhejiang Engineering Research Center of Intelligent Urban Infrastructure Hangzhou City UniversityHangzhou 310015China Department of Civil Engineering Zhejiang UniversityHangzhou 310058China

Urban subway tunnel construction inevitably disturbs the surrounding rock and causes the deformation of existing subway structures. Dynamic predictions of the tunnel horizontal displacement, tunnel ballast settlement, and tunnel differential settlement are important for ensuring the safety of buildings and tunnels. First, based on the Hangzhou Metro project, we analyzed the influence of construction on the deformation of existing subway structures and the difficulties and key points in monitoring. Then, a deformation prediction model, based on a back propagation(BP) neural network, was established with massive monitoring data. In particular, we analyzed the influence of four structures of the BP neural network on prediction performance, i.e., single input–single hidden layer–single output, multiple inputs–single hidden layer–single output, single input–double hidden layers–single output, and multiple inputs–double hidden layers–single output, and verified them using measured data.

关键词： Subway Horizontal displacement of tunnel Settlement of tunnel ballast Differential settlement of tunnel Deformation prediction Back propagation(BP)neural network

In situ TEM observation of magnetization-enhanced dislocation emission and motion for 60Fe40Ni alloy

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Chinese Science Bulletin 1997年第24期42卷 2064-2066页

作者： LI Hongqi, WANG Yanbin, chen qizhi CHU WuyangDepartment of Materials Physics, University of Science and Technology Beijing, Beijing 100083, China Department of Materials Physics University of Science and Technology Beijing Beijing China

TENSILE test for pure iron in the magnetic field with the intensity of 2 400 A/m indicated thatthe lower yield stress was decreased and the upper yield point disappeared in the magneticfield. This seems to show that magnetization can reduce the resistance of dislocation mo-tion. Up to now, however, direct proof of magnetization-enhanced dislocation emission andmotion is lacking.

关键词： magnetic field dislocation magnetic domain TEM.

BUTTERFLY MARTENSITE NUCLEATION IN AN Fe-Ni-V-C ALLOY

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Acta Metallurgica Sinica(English Letters) 1991年第6期4卷 414-418页

作者： chen qizhi WU Xingfang KE Jun (T Ko) University of Science and Technology Beijing,Beijing,China

The butterfly martensite nuclei in an Fe-Ni-V-C alloy were observed under TEM,they con- sist of enveloping dislocations with Burger's vector(1/2)[]_(fcc) and arrays of dislocations with Burger's vector(1/2)[10]_(fcc) piled up within the *** enveloping dislocations and the arrays of dislocations provide the required shear when the planes(11)_(fcc)move with each other to alter their stacking order and change into the planes(110)_(bcc) *** necessary adjustment of the spacings is provided by the dislocations in *** crystallographic relationship after double-shear is K-S one.

关键词： butterfly martensite nuclei enveloping dislocation piling dislocation

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液体中气-液射流特性的研究

化学反应工程与工艺 1989年第2期5卷 45-52页

作者：张奇志陈甘棠江苏常州江苏化工学院浙江大学

在气-液两相喷射式装置中气体或/和液体是经由单个(或多个)喷咀射入塔内的。本研究用频闪摄影技术对气、液向上共同喷射时液体中的气-液射流特性进行了实验研究,并建立了气泡直径分布函教及射流特征尺寸的关联式。同时,对射流两相区内... 详细信息

在气-液两相喷射式装置中气体或/和液体是经由单个(或多个)喷咀射入塔内的。本研究用频闪摄影技术对气、液向上共同喷射时液体中的气-液射流特性进行了实验研究,并建立了气泡直径分布函教及射流特征尺寸的关联式。同时,对射流两相区内两相的流动用一两相模型进行模拟,考察了喷咀直径、初始条件、液体压头和气泡直径对器内两相流动的影响。

关键词：气-液射流气泡尺寸分布二相模型