检索结果-南通市图书馆

盾尾注浆材料硬化特性对隧道和地层力学响应影响的有限元模拟研究

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

北京工业大学学报 2024年第6期50卷 711-723页

作者：路德春刘竹根林庆涛孔凡超杜修力北京工业大学岩土与地下工程研究所北京100124 清华大学土木工程系北京100084

为了探究注浆材料硬化和注浆压力的消散过程对软土地层和隧道衬砌受力变形的影响,以青岛某地铁隧道为背景,考虑盾构机与土体相互作用、衬砌-注浆层-土体相互作用,以及注浆材料硬化和注浆压力消散过程,基于ABAQUS有限元平台建立了盾构施... 详细信息

为了探究注浆材料硬化和注浆压力的消散过程对软土地层和隧道衬砌受力变形的影响,以青岛某地铁隧道为背景,考虑盾构机与土体相互作用、衬砌-注浆层-土体相互作用,以及注浆材料硬化和注浆压力消散过程,基于ABAQUS有限元平台建立了盾构施工精细化的有限元数值仿真模型,并利用实测地层沉降和隧道衬砌的收敛变形验证了数值模型的合理性。同时,对注浆材料初凝时间分别为0、2、6、12 h的数值模型进行了计算,获得了地层和隧道衬砌受力变形随注浆材料硬化过程的发展规律,以及注浆材料硬化特性对地层和隧道衬砌受力变形的影响规律。模拟结果表明:盾尾注浆8 h以内,地层的沉降和水平位移以及隧道衬砌的围岩压力和内力增加显著,注浆时间超过8 h后增加变得缓慢;注浆材料的初凝时间越长,地表沉降、地层水平位移和竖向位移则越大;衬砌拱顶和拱腰的径向收敛越大,拱底径向收敛则越小;衬砌的轴力和弯矩在注浆8 h以内增加显著。

关键词：盾构施工盾尾注浆硬化过程注浆压力消散有限元数值模拟地层变形衬砌力学响应

在线全文

学校读者我要写书评

暂无评论

溶藻芽孢杆菌的特性、作用机理及应用

环境污染与防治 2024年第9期46卷 1372-1377页

作者：焦鹤云孔凡超何培民邵留上海海洋大学海洋生态与环境学院上海201306 上海海洋大学水域环境生态上海高校工程研究中心上海201306

有害藻华(HABs)在全球范围内暴发,对水生态系统和人类生活健康都造成了一定的威胁。目前防治HABs的众多方法中,利用溶藻细菌抑藻一直是近年来的一个研究热点。其中,溶藻芽孢杆菌因具有抑藻效率高、稳定性高、生物安全性好,且兼备改善水... 详细信息

有害藻华(HABs)在全球范围内暴发,对水生态系统和人类生活健康都造成了一定的威胁。目前防治HABs的众多方法中,利用溶藻细菌抑藻一直是近年来的一个研究热点。其中,溶藻芽孢杆菌因具有抑藻效率高、稳定性高、生物安全性好,且兼备改善水质、提高水生动物免疫力等特点而备受关注。整理了目前为止有关溶藻芽孢杆菌的相关进展,总结了溶藻芽孢杆菌的作用机理和应用现状,同时对今后溶藻芽孢杆菌的研究方向进行了展望。

关键词：溶藻芽孢杆菌抑藻有害藻华应用

LARGE DEVIATIONS FOR SUMS OF INDEPENDENT RANDOM VARIABLES WITH DOMINATEDLY VARYING TAILS

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2007年第1期22卷 78-86页

作者： kong fanchao Zhang Ying Institutive of Mathematics and Computer Sciences Anhui University Hefei 230039 China

In this paper the large deviation results for partial and random sums Sn-ESn=n∑i=1Xi-n∑i=1EXi,n≥1;S（t）-ES（t）=N（t）∑i=1Xi-E（N（t）∑i=1Xi）,t≥0 are proved, where {N（t）;t ≥ 0} is a counting process of non-negative integer-valued random variables, and {Xn; n ≥ 1} are a sequence of independent non-negative random variables independent of {N（t）; t ≥ 0}. These results extend and improve some known conclusions.

关键词： heavy-tailed large deviation dominated variation.

Time-dependent surrounding soil pressure and mechanical response of tunnel lining induced by surrounding soil viscosity

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2021年第11期64卷 2453-2468页

作者： MIAO JinBo LU DeChun LIN QingTao kong fanchao DU XiuLi Institute of Geotechnical and Underground Engineering Beijing University of Technology'Beijing 100124China

A numerical simulation method of shield tunnel excavation is developed to capture the time-dependent deformation behaviour of surrounding soil. The simulation method consists of four parts:(i) an elastic-plastic-viscous constitutive model that can not only reasonably describe the viscous deformation behaviour of soil, but also appropriately calculate the plastic deformation under typical stress paths of excavation;(ii) simulation of main factors related to shield tunnel excavation, including the shield machine, face pressure, lining, grout behavior, and contacts between multiple media;(iii) a simulation procedure for excavation to reflect the process of shield tunnel excavation and achieve reasonable stress and strain fields at the end of the construction stage;(iv) a creep process that is used to investigate the long-term mechanical behaviours of the surrounding soil and tunnel lining. Taking the CK570H tunnel project in Taipei as the background, a numerical simulation is conducted by adopting the developed simulation method. Based on the simulation results, the radial and circumferential stresses acting on the lining, which are induced by the surrounding soil viscosity, are analysed. The rule of the mechanical response of lining, including its deformation, bending moment, and axial force, with time is revealed. On this basis, the long-term safety of the lining is evaluated.

关键词： tunnel surrounding soil pressure soil viscosity shield excavation numerical simulation method time-dependent behaviour

Novel hybrid method to predict the ground-displacement field caused by shallow tunnel excavation

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2023年第1期66卷 101-114页

作者： kong fanchao LU DeChun MA YiDing TIAN Tao YU HaiTao DU XiuLi Institute of Geotechnical and Underground Engineering Bejing University of TechnologyBejing 100124China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China

Based on machine-learning(ML) and analytical methods, a hybrid method is developed herein to predict the ground-displacement field(GDF) caused by tunneling. The extreme learning machine(ELM), as a single hidden layer feedforward neural network, is used as an ML model to predict maximum settlement smaxof the ground surface. The particle swarm optimization(PSO) algorithm is applied to optimize the parameters for the ELM method, namely, weight and bias values from the input layer to the hidden layer. The mean square error of the k-fold cross validation sets is considered the fitness function of the PSO algorithm. For 38 data samples from published papers, 30 samples are used as the training set, and 8 samples are used as the test set. For the test samples, the error of five samples ranges between-5 and 5 mm. The error of only one sample is slightly greater than 10 mm. The proposed PSO-ELM method demonstrates good prediction performance of smax. A deformation parameter of the nonuniform displacement mode for the tunnel cross-section is calibrated based on predicted smax. When the determined nonuniform displacement mode is used as the boundary condition of the tunnel cross-section, the GDF of a shallow circular tunnel is analytically predicted based on the complex-variable method prior to tunnel excavation. For a specific engineering case,i.e., the Heathrow Express tunnel, the proposed PSO-ELM-analytical method can well predict the surface-settlement trough curve, horizontal displacements at different depths, and vertical displacements above the tunnel.

关键词： extreme learning machine particle swarm optimization complex-variable method analytical solution of a shallow tunnel prediction method of ground-displacement field

Fractional viscoelastic solution of stratum displacement of a shallow tunnel under the surface slope condition

在线全文

学校读者我要写书评

暂无评论

Underground Space 2023年第3期10卷 233-247页

作者： fanchao kong Dechun Lu Chao Ma Chenpeng Shen Xiaodong Yang Xiuli Du Institute of Geotechnical and Underground Engineering Beijing University of TechnologyBeijing 100124China School of Civil and Transportation Engineering Beijing University of Civil Engineering and ArchitectureBeijing 102626China Beijing Urban Construction Design&Development Group Co. LimitedThe Third Design Institute of Railway InstituteBeijing 100034China College of Mechanical Engineering Beijing University of TechnologyBeijing 100124China

The unified displacement function(UDF)is presented to describe the deformation behaviours of the tunnel profile along with time under the surface slope *** on the discrete Fourier method,the third-order UDF in the physical plane is expanded to the Laurent series in the complex variable *** complex variable method is employed to derive the elastic analytical solution of stra-tum displacement,when the third-order UDF is taken as the displacement boundary condition of tunnel cross-section(DBCTC).The proposed elastic solution agrees well with the results of the finite element method for the consistent model,which verifies the correctness of the proposed analytical *** the corresponding principle and fractional Generalized Kelvin viscoelastic constitutive model,the fractional viscoelastic solution under the surface slope condition is *** time effect of stratum displacement is presented in two aspects:time-dependent DBCTC and time-dependent material *** parameter analysis is performed to investigate influences of deformation modes of the third-order UDF,slope angle,tunnel radius and fractional order on the time effect of stratum vertical and horizontal displacement.

关键词： Third-order unified displacement function Surface slope condition Fractional viscoelastic solution Complex variable method Discrete Fourier method

The Relationship between Financial Development and Industrial Restructuring --Based on Panel Data of 17 Areas of Shandong

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Review of Global Academics 2014年第4期1卷 304-306页

作者： kong fanchao Shandong university of Finance and Economics Jinan Shandong

Based on the Panel Data of Shan dong Province of 17 regions, by estimating varying coefficient models, studies the relationship between financial development and industrial *** results show that, on the whole, the financial development indicators-the scale and the efficiency can effectively promote industrial restructuring in all regions of Shandong province, but its role has obvious differences in different regions, so it can provide a basis for economic decision-making and financial policy advice.

关键词： Financial development Industrial restructuring panel data

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

电源外壳注塑成型模具设计

现代制造技术与装备 2024年第9期60卷 14-17页

作者：孔凡超陈佳春林诗济韩政洋朱睿琦林权武夷学院机电工程学院武夷山354300

文章针对服务器电源外壳注塑件的模具进行设计,为了提高注塑模具设计的效率和质量,利用Moldﬂow进行模流分析,并对充填时间、冷却分析、翘曲变形等开展预测评估。经过模流分析,产品成型最大翘曲变形量为0.4406 mm,冷却水路温差小于3℃,... 详细信息

文章针对服务器电源外壳注塑件的模具进行设计,为了提高注塑模具设计的效率和质量,利用Moldﬂow进行模流分析,并对充填时间、冷却分析、翘曲变形等开展预测评估。经过模流分析,产品成型最大翘曲变形量为0.4406 mm,冷却水路温差小于3℃,符合塑件生产技术要求。依据模流分析结果进行模具结构设计,采用侧浇口进料一模两腔型腔布局,设置定模直流循环水路和动模隔板水路,设计推杆联合斜销内抽芯的脱模方式,以及弹簧先复位机构等。

关键词：模具设计注塑成型电源外壳模流分析

在线全文

学校读者我要写书评

暂无评论

美国图书馆员职业能力观的演进及其特征

图书情报工作 2016年第21期60卷 39-45页

作者：孔繁超曲阜师范大学日照校区图书馆日照276826

[目的 /意义]了解和掌握美国图书馆员职业能力内涵的历史变迁和主要特征,以期对我国图书馆员职业能力建设有所借鉴。[方法 /过程]采用文献调研法,对美国图书馆员职业能力内涵的演进和职业能力观的特征进行分析和讨论。[结果 /结论]在美... 详细信息

[目的 /意义]了解和掌握美国图书馆员职业能力内涵的历史变迁和主要特征,以期对我国图书馆员职业能力建设有所借鉴。[方法 /过程]采用文献调研法,对美国图书馆员职业能力内涵的演进和职业能力观的特征进行分析和讨论。[结果 /结论]在美国"图书馆员职业能力"所包含的要素中,知识、技能、品性被认为是最核心的3个内容。在此基础上,美国"图书馆员职业能力"的内涵逐渐延伸与变形,形成了基于实践含义的"能力课程论"、基于社会含义的"社会能力论"、基于表层含义的"行为能力论"、基于现实含义的"标准能力论"、基于实质含义的"学习潜能论"等一系列能力理论体系。美国图书馆员职业能力观的主要特征表现在:社会建构性、文化敏锐性、读者中心性和动态发展性,而研究者采用的不同研究方法和研究视角是导致中美图书馆员职业能力观差异的根本原因。

关键词：图书馆员职业能力观研究方法论美国