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Non-dimensional analysis on blast wave propagation in foam concrete:Minimum thickness to avoid stress enhancement
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作者 Ya Yang Xiangzhen Kong Qin Fang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第6期30-46,共17页
Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau stage.However,stress enhancement rather than stress miti... Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau stage.However,stress enhancement rather than stress mitigation may happen when foam concrete is used as sacrificial claddings placed in the path of an incoming blast load.To investigate this interesting phenomenon,a one-dimensional difference model for blast wave propagation in foam concrete is firstly proposed and numerically solved by improving the second-order Godunov method.The difference model and numerical algorithm are validated against experimental results including both the stress mitigation and the stress enhancement.The difference model is then used to numerically analyze the blast wave propagation and deformation of material in which the effects of blast loads,stress-strain relation and length of foam concrete are considered.In particular,the concept of minimum thickness of foam concrete to avoid stress enhancement is proposed.Finally,non-dimensional analysis on the minimum thickness is conducted and an empirical formula is proposed by curve-fitting the numerical data,which can provide a reference for the application of foam concrete in defense engineering. 展开更多
关键词 foam concrete Blast wave propagation Non-dimensional analysis Stress enhancement
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Mechanical properties and associated seismic isolation effects of foamed concrete layer in rock tunnel 被引量:15
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作者 Shaosen Ma Weizhong Chen Wusheng Zhao 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2019年第1期159-171,共13页
Foamed concrete has a good energy absorption capability and can be used as seismic isolation material for tunnels. This study aims to investigate the mechanical properties and associated seismic isolation effects of f... Foamed concrete has a good energy absorption capability and can be used as seismic isolation material for tunnels. This study aims to investigate the mechanical properties and associated seismic isolation effects of foamed concrete layer in rock tunnel. For this, a series of uniaxial/triaxial compression tests was conducted to understand the effects of concrete density, confining stress and strain rate on the mechanical properties of foamed concrete. The direct shear tests were also performed to investigate the effects of concrete density and normal stress on the nonlinear behaviors of foamed concrete layer-lining interface. The test results showed that the mechanical properties of foamed concrete are significantly influenced by the concrete density. The foamed concrete also has high volumetric compressibility and strain-rate dependence. The peak stress. residual stress. shear stiffness and residual friction coefficient of the foamed concrete layer-lining interface are influenced by the foamed concrete density and normal stress applied. Then, a crushable foam constitutive model was constructed using ABAQUS software and a composite exponential model was also established to study the relationship between shear stress and shear displacement of the interface, in which their parameters were fitted based on the experimental results. Finally, a parametric analysis using the finite element method(FEM) was conducted to understand the influence of foamed concrete layer properties on the seismic isolation effect, including the density and thickness of the layer as well as the shear stiffness and residual friction coefficient of the interface. It was revealed that lower density and greater thickness in addition to smaller shear stiffness or residual friction coefficient of the foamed concrete layer could yield better seismic isolation effect, and the influences of the first two tend to be more significant. 展开更多
关键词 ROCK TUNNEL foamed concrete SEISMIC ISOLATION LAYER SEISMIC ISOLATION mechanism
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Preparation of High Performance Foamed Concrete from Cement,Sand and Mineral Admixtures 被引量:8
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作者 潘志华 Fujiwara Hiromi Wee Tionghuan 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2007年第2期295-298,共4页
The titled high performance foamed concrete was developed from Portland cement, ultra fine granulated blast-furnace slag, pulverized fly ash and condensed silica fume by means of pre-foaming process. The resultant foa... The titled high performance foamed concrete was developed from Portland cement, ultra fine granulated blast-furnace slag, pulverized fly ash and condensed silica fume by means of pre-foaming process. The resultant foamed concrete presents its thermal conductivity of about 0.16-0.75 W/(m·℃) and 28 d compressive strength of about 1.1-23.7 MPa when its mix proportion varies in the range of cement content 280 kg-650 kg/m^3, fly ash 42-97 kg/m^3, slag 64-146 kg/m^3, silica fume 34-78 kg/m^3, and sand 0-920 kg/m^3. The compressive strength of the foamed concrete with oven dried bulk density of 1500 kg/m^3 in appropriate mix proportion and with small amount of superplasticizer reached as high as 44.1 MPa. Meanwhile, the flesh foamed concrete behaves like an excellent flow-ability, therefore, is especially suitable for the application in case of massive foamed concrete casting in situ and in the case of filling casting into large volume underground irregular voids, except for pre-casting of building components like blocks, bricks, and wall panels. 展开更多
关键词 foamed concrete DENSITY compressive strength thermal conductivity
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Quantitative Analysis of Relationship Between Pore Structure and Compressive Strength of Foamed Concrete 被引量:2
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作者 Geng Fei Yin Wanyun +3 位作者 Xie Jianguang Liu Shoucheng Li Haoran Gui Jingneng 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2018年第3期556-564,共9页
The effect of dry density,water-cement ratio,the addition of fly ash,and sand content on the porosity and pore distribution of foamed concrete is investigated.Digital microscopy and Image J software are employed to ex... The effect of dry density,water-cement ratio,the addition of fly ash,and sand content on the porosity and pore distribution of foamed concrete is investigated.Digital microscopy and Image J software are employed to examine the landscape of pores with different sizes.Based on the Balshin empirical formula,a mathematical model is established to quantitatively predict the relationship between the pore structures and the compressive strength of foamed concrete.The results well demonstrate that there is a significant correlation between the modified formula and empirical parameters. 展开更多
关键词 foamed concrete POROSITY pore size compressive strength
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Tests on Alkali-Activated Slag Foamed Concrete with Various Water-Binder Ratios and Substitution Levels of Fly Ash 被引量:6
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作者 Keun-Hyeok Yang Kyung-Ho Lee 《Journal of Building Construction and Planning Research》 2013年第1期8-14,共7页
To provide basic data for the reasonable mixing design of the alkali-activated (AA) foamed concrete as a thermal insulation material for a floor heating system, 9 concrete mixes with a targeted dry density less than 4... To provide basic data for the reasonable mixing design of the alkali-activated (AA) foamed concrete as a thermal insulation material for a floor heating system, 9 concrete mixes with a targeted dry density less than 400 kg/m3 were tested. Ground granulated blast-furnace slag (GGBS) as a source material was activated by the following two types of alkali activators: 10% Ca(OH)2 and 4% Mg(NO3)2, and 2.5% Ca(OH)2 and 6.5% Na2SiO3. The main test parameters were water-to-binder (W/B) ratio and the substitution level (RFA) of fly ash (FA) for GGBS. Test results revealed that the dry density of AA GGBS foamed concrete was independent of the W/B ratio an RFA, whereas the compressive strength increased with the decrease in W/B ratio and with the increase in RFA up to 15%, beyond which it decreased. With the increase in the W/B ratio, the amount of macro capillaries and artificial air pores increased, which resulted in the decrease of compressive strength. The magnitude of the environmental loads of the AA GGBS foamed concrete is independent of the W/B ratio and RFA. The largest reduction percentage was found in the photochemical oxidation potential, being more than 99%. The reduction percentage was 87% - 93% for the global warming potential, 81% - 84% for abiotic depletion, 79% - 84% for acidification potential, 77% - 85% for eutrophication potential, and 73% - 83% for human toxicity potential. Ultimately, this study proved that the developed AA GGBS foamed concrete has a considerable promise as a sustainable construction material for nonstructural element. 展开更多
关键词 ALKALI-ACTIVATED foamed concrete Granulated Ground BLAST-FURNACE SLAG FLY ASH Water-to-Binder Ratio Environmental Load
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Lateral compression and energy absorption of foamed concrete-filled polyethylene circular pipe as yielding layer for high geo-stress soft rock tunnels 被引量:3
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作者 Chaoxuan Zhang Xianjun Tan +1 位作者 Hongming Tian Weizhong Chen 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2022年第5期1087-1096,共10页
Foamed concrete as energy absorption material for high geo-stress soft rock tunnels has been proven to be feasible due to its high compressibility and lightweight.However,the lengthy curing and defoaming problems caus... Foamed concrete as energy absorption material for high geo-stress soft rock tunnels has been proven to be feasible due to its high compressibility and lightweight.However,the lengthy curing and defoaming problems caused by the cast-in-place method of large-volume foamed concrete remain unsolved.In this study,we propose a novel energy absorber composed of foamed concrete-filled polyethylene(FC-PE)pipe and analyze its deformation and energy absorption capacity via quasi-static lateral compression experiments.Results show that FC-PE pipes exhibit typical three-stage deformation characteristics,comprising the elastic stage,the plastic plateau,and the densification stage.Furthermore,the plateau stress,energy absorption,and specific energy absorption of the specimens are 0.81–1.91 MPa,164–533 J,and 1.4–3.6 J/g,respectively.As the density of the foamed concrete increases,the plateau stress and energy absorption increase significantly.Conversely,the length of the plastic plateau and energy absorption efficiency decrease.Moreover,based on the vertical slice method,progressive compression of core material,and the 6 plastic hinges deformation mechanism of the pipe wall,a theoretical calculation method for effective energy absorption is established and achieves good agreement with experimental results,which is beneficial to the optimization of the composite structure. 展开更多
关键词 Soft rock Yielding layer foamed concrete Polyethylene pipe Lateral compression Energy absorption
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Study and application of a new type of foamed concrete wall in coal mines 被引量:3
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作者 Zi-Bo TANG Yong-Liang ZHAO De-Shun KONG Dan KAN 《Journal of Coal Science & Engineering(China)》 2013年第3期345-352,共8页
A new type of airtight wall with the combination of foamed concrete and pier support was designed in this study. Based on the theories and models related to the foamed concrete and blasting shock load, using the numer... A new type of airtight wall with the combination of foamed concrete and pier support was designed in this study. Based on the theories and models related to the foamed concrete and blasting shock load, using the numerical analysis method, this study obtains the new material's mechanical and destruction laws through analyzing its reaction to different conditions of load (mining and shock waves), airtight wall thickness (1.2, 1.5, 1.8, 2.1 m) and steel pipe diameters (400, 450, 500 and 600 mm). The results show that: ①foamed concrete can have very good suspension, and the pier column support is the main carrier of roof pressure; ② the damaged area of foamed concrete decreases as the foamed concrete thickness increases. Under impact loading, the thickness of the foamed concrete wall plays a more obvious role in retaining its integrity; ③under the same mining pressure, the damage area increases as the steel pipe diameter increases; ④ with additional mining stress increase, under whether static load or impact load, the stress on the foamed concrete and steel pipe will also increase gradually, therefore the actual airtight wall design will need to be based on specific circumstances in steel stress. 展开更多
关键词 airtight wall pier column foam concrete mining pressure
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Physical modeling of behaviors of cast-in-place concrete piled raft compared to free-standing pile group in sand 被引量:1
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作者 Mehdi Sharafkhah Issa Shooshpasha 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2018年第4期703-716,共14页
Similar to free-standing pile groups, piled raft foundations are conventionally designed in which the piles carry the total load of structure and the raft bearing capacity is not taken into account. Numerous studies i... Similar to free-standing pile groups, piled raft foundations are conventionally designed in which the piles carry the total load of structure and the raft bearing capacity is not taken into account. Numerous studies indicated that this method is too conservative. Only when the pile cap is elevated from the ground level,the raft bearing contribution can be neglected. In a piled raft foundation, pileesoileraft interaction is complicated. Although several numerical studies have been carried out to analyze the behaviors of piled raft foundations, very few experimental studies are reported in the literature. The available laboratory studies mainly focused on steel piles. The present study aims to compare the behaviors of piled raft foundations with free-standing pile groups in sand, using laboratory physical models. Cast-in-place concrete piles and concrete raft are used for the tests. The tests are conducted on single pile, single pile in pile group, unpiled raft, free-standing pile group and piled raft foundation. We examine the effects of the number of piles, the pile installation method and the interaction between different components of foundation. The results indicate that the ultimate bearing capacity of the piled raft foundation is considerably higher than that of the free-standing pile group with the same number of piles. With installation of the single pile in the group, the pile bearing capacity and stiffness increase. Installation of the piles beneath the raft decreases the bearing capacity of the raft. When the raft bearing capacity is not included in the design process, the allowable bearing capacity of the piled raft is underestimated by more than 200%. This deviation intensifies with increasing spacing of the piles. 展开更多
关键词 Free-standing pile group Piled raft Pileesoileraft interaction Physical modeling cast-in-place concrete piles
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BIM-based construction technologies for precast foamed lightweight concrete wallboards 被引量:1
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作者 Lin Jiankang Chen Zhongfan +2 位作者 Ding Xiaomeng Feng Yan Zhang Jiaheng 《Journal of Southeast University(English Edition)》 EI CAS 2022年第3期270-277,共8页
To promote the visualisation and informatisation of the construction process of precast foamed lightweight concrete wallboards(PFLCWs),from the analysis of the construction requirements of PFLCWs,three key constructio... To promote the visualisation and informatisation of the construction process of precast foamed lightweight concrete wallboards(PFLCWs),from the analysis of the construction requirements of PFLCWs,three key construction technologies based on building information modelling(BIM),namely,parameterised modelling for the PFLCW layout design,drawing generation to draw the PFLCW layout and quantity statistics for extracting PFLCW quantities,are proposed.Then,a reinforced concrete(RC)frame infilled with PFLCW is considered the test model to verify the feasibility of the aforementioned technologies.The results show that PFLCW layout design can be accomplished rapidly and visually using parameterised modelling technology.The PFLCW layout diagram can be generated directly using drawing generation technology.The proposed quantity statistics technology enables the automatic export of PFLCW bills of quantities.The built parameterised model helps construction workers rapidly and intuitively understand the specific layout details of PFLCWs.Moreover,the generated layout drawing and the bills of quantities based on the parameterised model can guide the production and on-site installation of PFLCWs.The research conclusions can serve as a practical guide and technical support for PFLCW engineering applications. 展开更多
关键词 building information modelling(BIM) precast foamed lightweight concrete wallboard(PFLCW) construction visualisation and informatisation parameterised modelling quantity statistics
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In-situ Monitoring the Setting Behavior of Foamed Concrete Using Ultrasonic Pulse Velocity Method
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作者 SHE Wei ZHANG Yunsheng +1 位作者 JONES MR GUO Panpan 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2013年第6期1146-1154,共9页
The applicability of ultrasonic pulse velocity (UPV) method to in-situ monitor setting and hardening process of foamed concrete (FC) was systematically investigated. The UPVs of various FC pastes were automaticall... The applicability of ultrasonic pulse velocity (UPV) method to in-situ monitor setting and hardening process of foamed concrete (FC) was systematically investigated. The UPVs of various FC pastes were automatically and continuously measured by a specially designed ultrasonic monitoring apparatus (UMA). Ultrasonic tests were performed on FC mixtures with different density (300, 500, 800 and 1 000 kg/m3), and different fly ash contents (0%, 20%, 40% and 60%). The influence of curing temperatures (20, 40, 60 and 80~C) was also studied. The experimental results show that three characteristic stages can be clearly identified during the setting process of an arbitrary FC paste: dormant stage, acceleration stage, and deceleration stage. Wet density, fly ash content, and curing temperature have great impact on setting behavior. A stepwise increase of the wet density results in shorter dormant stage and larger final UPV. Hydration reaction rate is obviously promoted with an increase in curing temperature. However, the addition fly ash retards the microstn,lcture formation. To aid in comparing with the ultrasonic results, the consistence spread test and Vicat needle test (VNT) were also conducted. A correlation between ultrasonic and VNT results was also established to evaluate the initial and final setting time of the FC mixtures. Finally, certain ranges of UPV with reasonable widths were suggested for the initial and final setting time, respectively. 展开更多
关键词 foamed concrete (FC) early age setting behavior ultrasonic monitoring setting time CONSISTENCE
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Field study of plastic tube cast-in-place concrete pile
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作者 陈永辉 曹德洪 +2 位作者 王新泉 杜海伟 张霆 《Journal of Central South University》 SCIE EI CAS 2008年第S2期195-202,共8页
The compositions, technical principles and construction equipments of a new piling method used for ground improvement plastic tube cast-in-place concrete pile were introduced. The results from static load tests on sin... The compositions, technical principles and construction equipments of a new piling method used for ground improvement plastic tube cast-in-place concrete pile were introduced. The results from static load tests on single piles with different forms of pile shoes and on their composite foundations were analyzed. The distribution patterns of axial force, shaft friction and toe resistance were studied based on the measurements taken from buried strain gauges. From the point of engineering application, the pile has merits in convenient quality control, high bearing capacity and reliable quality, showing higher reasonability, advancement and suitability than other ground improvement methods. The pile can be adopted properly to take place of ordinary ground improvement method, achieving greater economical and social benefits. 展开更多
关键词 PLASTIC tube cast-in-place concrete PILE SOFT ground improvement pile-supported type reinforced EMBANKMENT CONSTRUCTION equipment CONSTRUCTION workmanship
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Durability of Performance Foamed Concrete Mix Design with Silica Fume for Housing Development 被引量:1
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作者 Fahrizal Zulkamain Mahyuddin Ramli 《材料科学与工程(中英文版)》 2011年第5期518-527,共10页
关键词 混凝土配合比设计 泡沫性能 普通硅酸盐水泥 硅粉 混凝土抗压强度 耐久性 泡沫混凝土 房屋
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Computational Finite Element Modelling of Structural Behaviours of Precast Sandwiched Foamed Concrete Slab
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作者 Kingsley Ukanwa Noridah Mohamad James B. P. Lim 《Open Journal of Civil Engineering》 2015年第2期220-227,共8页
The structural behaviour of Precast Lightweight Foamed Concrete Panel (PLFP) under flexural load is investigated by using ABAQUS 6.13. The PLFP is made up of two Whyte’s with a polystyrene insulator placed in between... The structural behaviour of Precast Lightweight Foamed Concrete Panel (PLFP) under flexural load is investigated by using ABAQUS 6.13. The PLFP is made up of two Whyte’s with a polystyrene insulator placed in between them using a double shear truss connector of diameter 6mm placed at an angle 45&#176;. The panel is reinforced with both vertical and horizontal steel reinforcement of 9 mm diameter. Four panels with varying dimensions are simulated to investigate their Ultimate Strength and Load-deflection profile. The results show that the length to thickness ratio of the panel is the major contributing factor to the ultimate strength of the PLFP. From the load deflection curve, the panel with the least deflection has the highest thickness which also results in a high ultimate strength recorded at 34.43 KN. 展开更多
关键词 foamed concrete FLEXURAL Behaviour FINITE ELEMENT ABAQUS
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Comparative Study of the Thermal and Mechanical Properties of Foamed Concrete with Local Materials
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作者 Adelaïde Lareba Ouédraogo Sayouba Kabré +8 位作者 Etienne Malbila Abdoulaye Compaoré Ramatou Saré Paul Ilboudo Sié Kam Bruno Korgo Dieudonné Joseph Bathiebo Florent P. Kieno Philippe Blanchard 《World Journal of Engineering and Technology》 2022年第3期550-564,共15页
Living in a habitat with comfort is requested by all. Cinder block bricks have poor thermal properties, leading people to use fan heaters and air conditioners to regain comfort. To overcome this problem of thermal dis... Living in a habitat with comfort is requested by all. Cinder block bricks have poor thermal properties, leading people to use fan heaters and air conditioners to regain comfort. To overcome this problem of thermal discomfort in buildings, we used lightweight concrete such as foamed concrete which is a material that has improved thermal properties for thermal comfort. In addition, this material was compared with local materials used for the construction of buildings such as BTC, adobe and BLT mixed with binders. The results showed that foamed concrete is a material that has good thermal and mechanical properties compared to local materials mixed with binders. The foamed concrete having acceptable thermo-mechanical properties was that having a density of 930 kg/m<sup>3</sup>. It has a thermal resistance of 0.4 m<sup>2</sup>·K/W for a thickness of 20 cm. The foamed concrete having acceptable thermo-mechanical properties was that having a density of 930 kg/m3</sup>. It has a thermal resistance of 0.4 m2</sup>·K/W for a thickness of 20 cm. For sunshine on a daily cycle equal to 12 hours, the characteristic thickness achieved by this material is 7.29 cm. It also has a shallow depth of heat diffusion having a lower thickness than other materials. This shows that foamed concrete is a promising material for the construction of buildings. 展开更多
关键词 foamed concrete Thermo-Mechanical Properties COMPARISON Local Materi-als
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Design and construction of high and large span cast-in-place reinforced concrete cantilever flowering frame beam
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作者 WANG Rui ZHEN Liang +2 位作者 WAN Chao WU Jing SHEN Yan-jun 《Journal of Civil Engineering and Architecture》 2009年第5期58-62,共5页
The high and large span cast-in-place reinforced concrete cantilever structure of the office building of some court, which is located I-steel at the cantilever and used steel pipe scaffold as the support, has guarante... The high and large span cast-in-place reinforced concrete cantilever structure of the office building of some court, which is located I-steel at the cantilever and used steel pipe scaffold as the support, has guaranteed the frame body and structure security by the frame body calculating, on-site test and reasonable construction order. 展开更多
关键词 cast-in-place reinforced concrete support of cantilever structure high and long span design and construction
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Hardening Properties of Foamed Concrete with Circulating Fluidized Bed Boiler Ash, Blast Furnace Slag, and Desulfurization Gypsum as the Binder
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作者 Seunghyun Na Woonggeol Lee Myongshin Song 《Open Journal of Civil Engineering》 2021年第3期301-316,共16页
Recently, a large amount of circulating fluidized bed boiler ash (CFBA) and desulfurization gypsum (DSG) has been produced, and it is essential to develop technology to utilize them. These materials have CaO and SO<... Recently, a large amount of circulating fluidized bed boiler ash (CFBA) and desulfurization gypsum (DSG) has been produced, and it is essential to develop technology to utilize them. These materials have CaO and SO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">, which </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> considered to be a stimulant for blast furnace slag (BFS). This study presents an experimental investigation of the compressive strength and heavy metal ions immobilization properties of cement-free materials comprising CFBA, BFS, and DSG. The feasibility of manufacturing foamed concrete using these materials was examined, and field test of foamed concrete was conducted. Experimentally, the flow, compressive strength, and heavy metal ions concentration were evaluated via inductively coupled plasma atomic emission spectroscopy (ICP</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">AES) of the paste and foamed concrete. The experimental investigation revealed the self-healing hardening ability of fluidized bed boiler ash. In addition, the compressive strength was increased with the increasing replacement rates of BFS and DSG in the CFBA paste, and the compressive strength of 14.6</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> - </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">17.2 MPa was recorded over 28 days of curing. From the result obtained, the feasibility of manufacturing foamed concrete with a foam volume </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">of </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">120 L, incorporating the aforementioned materials, is confirmed. It was also found that after 28 days of age, a 7.9-MPa compressive strength of the foamed concrete was attained, and heavy metal ions elution in this foamed concrete was also significantly reduced. Therefore, CFBA, BFS, and DSG could be used as a binder for the foamed concrete. 展开更多
关键词 Circulating Fluidized Bed Boiler Ash Compressive Strength foamed concrete Heavy Metal Ions Immobilization Field Test
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Experimental Investigation on Transmission of Stress Waves in Sandwich Samples Made of Foam Concrete 被引量:4
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作者 SHEN Jun REN Xinjian 《Defence Technology(防务技术)》 SCIE EI CAS 2013年第2期139-144,共6页
A series of impact tests of sandwich samples were completed using a large-diameter split Hopkinson pressure bar (SHPB)device at different velocities. The interlayer is made of foam concrete, loess or sand. The stress ... A series of impact tests of sandwich samples were completed using a large-diameter split Hopkinson pressure bar (SHPB)device at different velocities. The interlayer is made of foam concrete, loess or sand. The stress peak value decay, energy decay and waveform dispersion characters are studied by comparing the incident waves with the transmission waves. The tests indicate that the foam concrete has the best capabilities of shock resistance and energy absorption, the loess comes second, and the sand takes third place. 展开更多
关键词 non-metallic inorganic material foam concrete SHPB stress wave energy absorption
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Development of a new type of foam concrete and its application on stability analysis of large-span soft rock tunnel 被引量:6
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作者 王辉 陈卫忠 +2 位作者 谭贤君 田洪铭 曹俊杰 《Journal of Central South University》 SCIE EI CAS 2012年第11期3305-3310,共6页
The long-term stability of large-span soft rock tunnel is influenced greatly by the creep effect of surrounding rock.The development of a new type of foam concrete which has the property of high compressibility and lo... The long-term stability of large-span soft rock tunnel is influenced greatly by the creep effect of surrounding rock.The development of a new type of foam concrete which has the property of high compressibility and low ductility was introduced.And it was made as filling material of reserved deformation layer between the first lining and the second lining used in large-span soft rock tunnel.The effect of the new type of foam concrete was simulated as filling material of reserved deformation layer using numerical simulation.Through the comparison with the common large-span soft rock tunnel,the vault settlement and surrounding convergence are reduced by about 61% and 45%,respectively,after creep of 100 a.And in the second lining,the plastic zone reduces apparently and the maximum equivalent plastic strain decreases relatively.So,it can be found that the application of the new type of foam concrete as the filling material of reserved deformation layer can relieve the excessive force in second lining induced by rock creep,reduce its deformation and improve the stability of tunnel. 展开更多
关键词 foam concrete large-span soft rock tunnel stability analysis numerical simulation
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Field observation of the thermal disturbance and freezeback processes of cast-in-place pile foundations in warm permafrost regions
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作者 Xin Hou Ji Chen +4 位作者 YouQian Liu PengFei Rui JingYi Zhao ShouHong Zhang HaiMing Dang 《Research in Cold and Arid Regions》 CSCD 2023年第1期18-26,共9页
The bearing capacity of pile foundations is affected by the temperature of the frozen soil around pile foundations.The construction process and the hydration heat of cast-in-place(CIP)pile foundations affect the therm... The bearing capacity of pile foundations is affected by the temperature of the frozen soil around pile foundations.The construction process and the hydration heat of cast-in-place(CIP)pile foundations affect the thermal stability of permafrost.In this paper,temperature data from inside multiple CIP piles,borehole observations of ground thermal status adjacent to the foundations and local weather stations were monitored in warm permafrost regions to study the thermal influence process of CIP pile foundations.The following conclusions are drawn from the field observation data.(1)The early temperature change process of different CIP piles is different,and the differences gradually diminish over time.(2)The initial concrete temperature is linearly related with the air temperature,net radiation and wind speed within 1 h before the completion of concrete pouring;the contributions of the air temperature,net radiation,and wind speed to the initial concrete temperature are 51.9%,20.3%and 27.9%,respectively.(3)The outer boundary of the thermal disturbance annulus is approximately 2 m away from the pile center.It took more than 224 days for the soil around the CIP piles to return to the natural permafrost temperature at the study site. 展开更多
关键词 PERMAFROST cast-in-place pile foundations Thermal disturbance Freezeback process Initial concrete temperature
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Influence of the penetration of adjacent X-section cast-in-place concrete(XCC)pile on the existing XCC pile in sand
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作者 Peng ZHOU Jianhui XU +3 位作者 Changjie XU Guangwei CAO Jie CUP Xuanming DING 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2024年第7期557-572,共16页
A series of small-scale 1g X-section cast-in-place concrete(XCC)pile-penetration model tests were conducted to study the effects of soil density and pile geometry on the lateral responses of an existing pile and the v... A series of small-scale 1g X-section cast-in-place concrete(XCC)pile-penetration model tests were conducted to study the effects of soil density and pile geometry on the lateral responses of an existing pile and the variations in surrounding soil stress.The results showed that the bending patterns of existing XCC piles varied with penetration depth.The lateral response of the existing pile was sensitive to the change in relative density and pile geometry.For example,the bending moment of the existing pile increased along with these parameters.The development of the radial stressσ′r/σ′v0 of the soil around an existing pile showed different trends at various depths during the penetration of the adjacent pile.Moreover,the change in radial stress during the penetration of the XCC pile did not exhibit the“h/R effect”that was observed in the free-field soil,due to the shielding effect of the existing piles.The peak value of radial stressσ′r_max/σ′v0 decreased exponentially as the radial distance r/R increased.The attenuation ofσ′r_max/σ′v0 with r/R in the loose sand was faster than in the medium-dense or dense sands.Theσ′r_max/σ′v0 at the same soil location increased with the cross-section geometry parameter. 展开更多
关键词 X-section cast-in-place concrete(XCC)pile Test PENETRATION SAND Lateral response Radial stress
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