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后压浆 1

地下尾矿库 1

堆石混凝土坝 1

尾矿 1

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无尾矿 1

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胶结土坝 1

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- and temperature-dependence of compressive and tensile behaviors of polypropylene fiber-reinforced cementedpaste backfill

《结构与土木工程前沿（英文）》 2021年 第15卷 第4期   页码 1025-1037 doi: 10.1007/s11709-021-0741-9

摘要： The understanding of compressive and tensile behaviors of polypropylene fiber-reinforced cemented paste backfill (FR-CPB) play crucial roles in the successful implementation of reinforcement technique in underground mine backfilling operations. However, very limited studies have been performed to gain insight into the evolution of compressive and tensile behaviors and associated mechanical properties of FR-CPB under various curing temperatures from early to advanced ages. Thus, this study aims to investigate the time (7, 28, and 90 d)- and temperature (20°C, 35°C, and 45°C)-dependence of constitutive behavior and mechanical properties of FR-CPB. The obtained results show that pre- and post-failure behaviors of FR-CPB demonstrate strongly curing temperature-dependence from early to advanced ages. Moreover, the pseudo-hardening behavior is sensitive to curing temperature, especially at early ages. Furthermore, the mechanical properties including elastic modulus, material stiffness, strengths, brittleness, cohesion, and internal friction angle of FR-CPB show increasing trends with curing temperature as curing time elapses. Additionally, a predictive model is developed to capture the strong correlation between compressive and tensile strength of FR-CPB. The findings of this study will contribute to the successful implementation of FR-CPB technology.

关键词： cemented paste backfill     fiber reinforcement     constitutive behavior     temperature     tailings    

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Experimental investigation of evolutive mode-I and mode-II fracture behavior of fiber-reinforced cementedpaste backfill: Effect of curing temperature and curing time

《结构与土木工程前沿（英文）》 2023年 第17卷 第2期   页码 256-270 doi: 10.1007/s11709-022-0924-z

摘要： The curing temperature-dependent cement hydration causes the nonlinear evolution of fracture behavior and properties of fiber-reinforced cemented paste backfill (CPB) and thus influences the stability of mine backfill materials in deep mines. Therefore, the coupled effect of curing temperature (20, 35, and 45 °C) and cement hydration at different curing times (3, 7, and 28 d) on the mode-I and mode-II fracture behavior and properties of fiber-reinforced CPB is investigated. A comprehensive experimental testing program consisting of semicircular bend tests, direct shear tests, measurement of volumetric water content and matric suction, TG/DTG tests, and SEM observation is carried out. The results show that the coupled thermochemical effect results in strongly nonlinear development of pre- and post-peak behavior of fiber-reinforced CPB. Moreover, the results discover a positive linear correlation between fracture toughness and shear strength parameters and also reveal the vital role played by matric suction in the formation of fracture toughness. Furthermore, predictive functions are developed to estimate the coupled thermochemical effect on the development of KIc and KIIc. Therefore, the findings and the developed mathematical tools have the potential to promote the successful application of fiber-reinforced CPB technology in deep underground mines.

关键词： fiber reinforcement     cemented paste backfill     fracture behavior     underground mine     cement hydration    

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Multiscale mechanical modeling of hydrated cement paste under tensile load using the combined DEM-MD

Yue HOU, Linbing WANG

《结构与土木工程前沿（英文）》 2017年 第11卷 第3期   页码 270-278 doi: 10.1007/s11709-017-0408-8

摘要： In this paper, a combined DEM-MD method is proposed to simulate the crack failure process of Hydrated Cement Paste (HCP) under a tensile force. A three-dimensional (3D) multiscale mechanical model is established using the combined Discrete Element Method (DEM)-Molecular Dynamics (MD) method in LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator). In the 3D model, HCP consists of discrete particles and atoms. Simulation results show that the combined DEM-MD model is computationally efficient with good accuracy in predicting tensile failures of HCP.

关键词： hydrated cement paste     multiscale     MD simulation     DEM    

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胶结颗粒料坝——环境友好的新坝型

贾金生, Michel Lino, 金峰, 郑璀莹

《工程（英文）》 2016年 第2卷 第4期   页码 490-497 doi: 10.1016/J.ENG.2016.04.003

摘要：

笔者于2009年提出了胶结颗粒料坝的概念，目的在于修建更安全、更经济的环境友好的大坝。该坝型包括胶结砂砾石坝(曾用名胶凝砂砾石坝)、堆石混凝土坝(或胶结堆石坝)和胶结土坝。本文基于研究和实践，进一步阐述了胶结颗粒料坝的概念和原则，介绍了胶结砂砾石坝、堆石混凝土坝和胶结土坝的新进展。

关键词： 胶结颗粒料坝     胶结砂砾石坝     堆石混凝土坝     胶结堆石坝     胶结土坝     材料特性    

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Research and application of visual location technology for solder paste printing based on machine vision

Luosi WEI, Zongxia JIAO

《机械工程前沿（英文）》 2009年 第4卷 第2期   页码 184-191 doi: 10.1007/s11465-009-0034-9

摘要： A location system is very important for solder paste printing in the process of surface mount technology (SMT). Using machine vision technology to complete the location mission is new and very efficient. This paper presents an integrated visual location system for solder paste printing based on machine vision. The working principle of solder paste printing is introduced and then the design and implementation of the visual location system are described. In the system, two key techniques are completed by secondary development based on VisionPro. One is accurate image location solved by the pattern-based location algorithms of PatMax. The other one is camera calibration that is achieved by image warping technology through the checkerboard plate. Moreover, the system can provide good performances such as high image locating accuracy with 1/40 sub-pixels, high anti-jamming, and high-speed location of objects whose appearance is rotated, scaled, and/or stretched.

关键词： machine vision     visual location     solder paste printing     VisionPro    

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Upper bound solution to seismic active earth pressure of submerged backfill subjected to partial drainage

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1480-1493 doi: 10.1007/s11709-021-0776-y

摘要： In waterfront geotechnical engineering, seismic and drainage conditions must be considered in the design of retaining structures. This paper proposes a general analytical method to evaluate the seismic active earth pressure on a retaining wall with backfill subjected to partial steady seepage flow under seismic conditions. The method comprises the following steps: i) determination of the total head, ii) upper bound solution of seismic active earth thrust, and iii) deduction for the earth pressure distribution. The determination of total head h(x,z) relies on the Fourier series expansions, and the expressions of the seismic active earth thrust and pressure are derived by using the upper bound theorem. Parametric studies reveal that insufficient drainage and earthquakes are crucial factors that cause unfavorable earth pressure. The numerical results confirm the validity of the total head distribution. Comparisons indicate that the proposed method is consistent with other relevant existing methods in terms of predicting seismic active earth pressure. The method can be applied to the seismic design of waterfront retaining walls.

关键词： seismic active earth pressure     partial seepage flow     pore pressure     anisotropy     upper bound theorem    

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Application of random set method in a deep excavation: based on a case study in Tehran cemented alluvium

Arash SEKHAVATIAN, Asskar Janalizadeh CHOOBBASTI

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 66-80 doi: 10.1007/s11709-018-0461-y

摘要： The design of high-rise buildings often necessitates ground excavation, where buildings are in close proximity to the construction, thus there is a potential for damage to these structures. This paper studies an efficient user-friendly framework for dealing with uncertainties in a deep excavation in layers of cemented coarse grained soil located in Tehran, Iran by non-deterministic Random Set (RS) method. In order to enhance the acceptability of the method among engineers, a pertinent code was written in FISH language of FLAC2D software which enables the designers to run all simulations simultaneously, without cumbersome procedure of changing input variables in every individual analysis. This could drastically decrease the computational effort and cost imposed to the project, which is of great importance especially to the owners. The results are presented in terms of probability of occurrence and most likely values of the horizontal displacement at top of the wall at every stage of construction. Moreover, a methodology for assessing the credibility of the uncertainty model is presented using a quality indicator. It was concluded that performing RS analysis before the beginning of every stage could cause great economical savings, while improving the safety of the project.

关键词： uncertainty     reliability analysis     deep excavations     random set method     finite difference method    

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Microstructural and photocatalytic characterization of cement-paste sol-gel synthesized titanium dioxide

Elena CERRO-PRADA,Miguel MANSO,Vicente TORRES,Jesús SORIANO

《结构与土木工程前沿（英文）》 2016年 第10卷 第2期   页码 189-197 doi: 10.1007/s11709-015-0326-6

摘要： A route for the in paste synthesis of TiO loaded cement is described. TiO sols are blended with fresh cement paste as an alternative process to add photocatalytic functionality to cement. The modification of cement paste structure after the addition of TiO sols is analyzed by XRD, SEM and TGA. As a particular microstructural feature, TiO containing calcium silicate hydrate (C-H-S) particles are identified as networking centers of a C-S-H gel fiber matrix. The increase of the TiO sol concentration induces a decrease of pore size and an increase in the specific surface area in the cement composites. The photocatalytic activity of the TiO /cement system is evaluated from the degradation of Methylene Blue (MB) under UV irradiation, monitored through the absorbance at 665 nm. The results show that, although TiO phases reveal no long range order structure, the cement paste exothermal treatment in presence of hydrate products and alkaline conditions leads to a photocatalytic composite. Such new cement matrix may be twofold advantageous since it additionally promotes the formation of C-S-H gel, main determinant of cement mechanical properties.

关键词： cement composites     photocatalytic TiO2     sol-gel     C-S-H gel     microstructure    

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Investigation on drilling-grinding of CFRP

Yanming QUAN, Wenwang ZHONG

《机械工程前沿（英文）》 2009年 第4卷 第1期   页码 60-63 doi: 10.1007/s11465-009-0008-y

摘要： It is difficult to machine polymer matrix composites reinforced by carbon fibre, and the hole-making process is the most necessary machining process for composite plate products. Conventional drills have a very short life in the drilling of this kind of composites and the quality of the hole is very poor. In this paper, the cemented or plated diamond core tools are tested to make holes in carbon fibre/epoxy composite plates. The effects of machining parameters, cooling and chip removal on the tool life, and the hole quality are investigated. Results indicate that the material removal mechanism of the two kinds of diamond tools is not like the cutting effect of the conventional solid twist drilling but similar to that of grinding. Satisfactory effects in making holes in the composites are obtained— quite acceptable machined hole quality, low costs, and long wear-resistant endurance.

关键词： composites     drilling-grinding     cemented/plated diamond     tool life     machined quality    

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Effect of earth reinforcement, soil properties and wall properties on bridge MSE walls

《结构与土木工程前沿（英文）》 2021年 第15卷 第5期   页码 1209-1221 doi: 10.1007/s11709-021-0764-2

摘要： Mechanically stabilized earth (MSE) retaining walls are popular for highway bridge structures. They have precast concrete panels attached to earth reinforcement. The panels are designed to have some lateral movement. However, in some cases, excessive movement and even complete dislocation of the panels have been observed. In this study, 3-D numerical modeling involving an existing MSE wall was undertaken to investigate various wall parameters. The effects of pore pressure, soil cohesion, earth reinforcement type and length, breakage/slippage of reinforcement and concrete strength, were examined. Results showed that the wall movement is affected by soil pore pressure and reinforcement integrity and length, and unaffected by concrete strength. Soil cohesion has a minor effect, while the movement increased by 13–20 mm for flexible geogrid reinforced walls compared with the steel grid walls. The steel grid stresses were below yielding, while the geogrid experienced significant stresses without rupture. Geogrid reinforcement may be used taking account of slippage resistance and wall movement. If steel grid is used, non-cohesive soil is recommended to minimize corrosion. Proper soil drainage is important for control of pore pressure.

关键词： mechanically stabilized earth walls     precast concrete panels     backfill soil     finite element modeling     earth reinforcement    

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Seismic response of precast reinforced concrete wall subjected to cyclic in-plane and constant out-of-plane loading

《结构与土木工程前沿（英文）》 2021年 第15卷 第5期   页码 1128-1143 doi: 10.1007/s11709-021-0753-5

摘要： This paper provides insight into the seismic behavior of a full-scale precast reinforced concrete wall under in-plane cyclic loading combined with out-of-plane loading replicated by sand backfill to simulate the actual condition of basement walls. The tested wall exhibited flexural cracks, owing to the high aspect ratio and considerable out-of-plane movement due to lateral pressure from the backfill. The wall performed satisfactorily by exhibiting competent seismic parameters and deformation characteristics governed by its ductile response in the nonlinear phase during the test with smaller residual drift. Numerical analysis was conducted to validate experimental findings, which complied with each other. The numerical model was used to conduct parametric studies to study the effect of backfill density and aspect ratio on seismic response of the proposed precast wall system. The in-plane capacity of walls reduced, while deformation characteristics were unaffected by the increase in backfill density. An increase in aspect ratio leads to a reduction in in-plane capacity and an increase in drift. Curves between the ratio of in-plane yield capacity and design shear load of walls are proposed for the backfill density, which may be adopted to determine the in-plane yield capacity of the basement walls based on their design shear.

关键词： precast wall     basement wall     out-of-plane response     quasi-static test     sand backfill     seismic parameters    

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An investigation into the properties of ternary and binary cement pastes containing glass powder

Marcelo Frota BAZHUNI, Mahsa KAMALI, Ali GHAHREMANINEZHAD

《结构与土木工程前沿（英文）》 2019年 第13卷 第3期   页码 741-750 doi: 10.1007/s11709-018-0511-5

摘要： The properties of binary and ternary cement pastes containing glass powder (GP) were examined. Hydration at early age was evaluated using semi-adiabatic calorimetry and at late ages using non-evaporable water content and thermogravimetric analysis. The transport characteristic was assessed by measuring electrical resistivity. The binary paste with slag showed the highest hydration activity compared to the binary pastes with GP and fly ash (FA). The results indicated that the pozzolanic behavior of the binary paste with GP was less than that of the binary pastes with slag or FA at late ages. An increase in the electrical resistivity and compressive strength of the binary paste with GP compared to other modified pastes at late ages was observed. It was shown that GP tends to increase the drying shrinkage of the pastes. Ternary pastes containing GP did not exhibit synergistic enhancements compared to the respective binary pastes.

关键词： cement paste     glass powder     pozzolanic reaction     supplementary cementitious material    

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金属矿山尾矿问题及其综合利用与治理

蔡嗣经,杨鹏

《中国工程科学》 2000年 第2卷 第4期   页码 89-92

摘要：

我国金属矿山在地面积存的尾矿已达40多亿t，并以每年约2.1亿t的速度在增长。金属矿山尾矿的主要特点为颗粒极细、数量极大、毒性很强、浓度很低。尾矿库占用大量土地，尾矿库工程事故，尾矿对地面环境和地下水源的污染等，迫切需要采用新技术开展对尾矿综合利用和治理的研究与开发，包括回收利用尾矿中的金属和非金属元素，利用尾矿制作建筑材料或磁性肥料；采用各种措施全面治理尾矿，如设立地下尾矿库，利用地面尾矿库作排土场，尾矿膏体地面无坝堆放与同步复垦等，其最终目标是建立“无尾矿山”。

关键词： 金属矿山     尾矿     环境污染     地下尾矿库     尾矿膏体     无尾矿    

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Effect of nonionic side chain length of polycarboxylate-ether-based high-range water-reducing admixture on properties of cementitious systems

Süleyman ÖZEN, Muhammet Gökhan ALTUN, Ali MARDANI-AGHABAGLOU, Kambiz RAMYAR

《结构与土木工程前沿（英文）》 2020年 第14卷 第6期   页码 1573-1582 doi: 10.1007/s11709-020-0680-x

摘要： Despite the large variations in the behaviors of water-reducing admixtures upon changes in their structures, most previous reports on the cement-admixture compatibility did not provide sufficient information on the structure of the admixture. Hence, the evaluation and generalization of the reports on the cement-admixture compatibility are challenging. In this study, three different polycarboxylate-ether-based water-reducing admixtures with the same free nonionic content, anionic/nonionic molar ratio, and main chain length and different side chain lengths were produced. The compatibility of these admixtures with a CEM I 42.5R-type cement was investigated. In addition, an analysis of variance was performed on the experiment results to evaluate the contributions of the admixture type, admixture/cement ratio, and elapsing time to the Marsh funnel flow time, mini-slump, slump flow, and compressive strength. The water-reducing admixtures having long or short side chains reduced the initial flow characteristics of the cementitious systems. However, the admixture having the shortest side chain was better with regard to flow retention. The side chain length of the admixture did not have significant effects on the compressive strength and water absorption capacity of the mortar mixtures and mini-slump performances of the cement paste mixtures. Regarding the behaviors of the admixtures in the cementitious systems, an optimal admixture side chain molecular weight is proposed.

关键词： water-reducing admixture     side chain length     cement paste     fluidity     compressive strength    

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大跨径悬索桥钢塔塔底钢混连接处承压板后压浆施工技术

张平,蒋建,董勤军,蔡伟,刘颖

《中国工程科学》 2010年 第12卷 第4期   页码 53-57

摘要：

泰州大桥为三塔两跨悬索桥，中塔纵桥向为人字型钢塔，两条斜腿在塔座顶面用螺杆锚固，通过钢塔D0段承压板与塔座顶面传递压力。塔座顶面混凝土具有双向斜坡度，在塔座顶面预留压浆空隙，待钢塔D0段安装定位后，再对预留空隙采用压浆机压入无收缩高强度水泥浆作为承压板的支承面。文章简要介绍了D0段承压板压浆施工技术及施工工艺。

关键词： 高强度     自流平     无收缩     后压浆     工艺    

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标题 作者 时间 类型 操作

- and temperature-dependence of compressive and tensile behaviors of polypropylene fiber-reinforced cementedpaste backfill

期刊论文

Experimental investigation of evolutive mode-I and mode-II fracture behavior of fiber-reinforced cementedpaste backfill: Effect of curing temperature and curing time

期刊论文

Multiscale mechanical modeling of hydrated cement paste under tensile load using the combined DEM-MD

Yue HOU, Linbing WANG

期刊论文

胶结颗粒料坝——环境友好的新坝型

贾金生, Michel Lino, 金峰, 郑璀莹

期刊论文

Research and application of visual location technology for solder paste printing based on machine vision

Luosi WEI, Zongxia JIAO

期刊论文

Upper bound solution to seismic active earth pressure of submerged backfill subjected to partial drainage

期刊论文

Application of random set method in a deep excavation: based on a case study in Tehran cemented alluvium

Arash SEKHAVATIAN, Asskar Janalizadeh CHOOBBASTI

期刊论文

Microstructural and photocatalytic characterization of cement-paste sol-gel synthesized titanium dioxide

Elena CERRO-PRADA,Miguel MANSO,Vicente TORRES,Jesús SORIANO

期刊论文

Investigation on drilling-grinding of CFRP

Yanming QUAN, Wenwang ZHONG

期刊论文

Effect of earth reinforcement, soil properties and wall properties on bridge MSE walls

期刊论文

Seismic response of precast reinforced concrete wall subjected to cyclic in-plane and constant out-of-plane loading

期刊论文

An investigation into the properties of ternary and binary cement pastes containing glass powder

Marcelo Frota BAZHUNI, Mahsa KAMALI, Ali GHAHREMANINEZHAD

期刊论文

金属矿山尾矿问题及其综合利用与治理

蔡嗣经,杨鹏

期刊论文

Effect of nonionic side chain length of polycarboxylate-ether-based high-range water-reducing admixture on properties of cementitious systems

Süleyman ÖZEN, Muhammet Gökhan ALTUN, Ali MARDANI-AGHABAGLOU, Kambiz RAMYAR

期刊论文

大跨径悬索桥钢塔塔底钢混连接处承压板后压浆施工技术

张平,蒋建,董勤军,蔡伟,刘颖

期刊论文