作者： Zhang, Genbao;Chen, Changfu*;Zornberg, Jorge G.;Morsy, Amr M.;Mao, Fengshan

期刊： Acta Geotechnica,2020年15(8):2159-2177 ISSN：1861-1125

通讯作者： Chen, Changfu

作者机构： [Zhang, Genbao] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Hunan, Peoples R China.;[Mao, Fengshan; Chen, Changfu] Hunan Univ, Minist Educ, Key Lab Bldg Safety & Energy Efficiency, Changsha 410082, Hunan, Peoples R China.;[Mao, Fengshan; Chen, Changfu] Hunan Univ, Coll Civil Engn, Changsha 410082, Hunan, Peoples R China.;[Zornberg, Jorge G.] Univ Texas Austin, Dept Civil Architecture & Environm Engn, Austin, TX 78712 USA.;[Morsy, Amr M.] Cairo Univ, Dept Civil Engn, Giza 12613, Egypt.

通讯机构： [Chen, Changfu] H;Hunan Univ, Minist Educ, Key Lab Bldg Safety & Energy Efficiency, Changsha 410082, Hunan, Peoples R China.;Hunan Univ, Coll Civil Engn, Changsha 410082, Hunan, Peoples R China.

关键词： Anchor–soil interface;Hybrid rheological model;Interface creep;Pullout test;Shear strength

摘要： This study aims at investigating the influence of moisture conditions on interface shear behavior of element-grouted anchor specimens embedded in clayey soils. The tests involved comparatively short embedment lengths and a device that was specially designed to facilitate moisture conditioning. Rapidly loaded pullout tests as well as pullout tests under sustained (creep) loading were conducted to characterize both the short-term and long-term ultimate shear strength of anchor–soil interfaces. Both values of the interface shear strength were found to decrease exponentially with increasing moisture content values, although their ratio was found to show a linearly decreasing trend with increasing moisture content. The interface shear creep response under pullout conditions was characterized by a rheological hybrid model that could be calibrated using experimental measurements obtained under increasing stress levels. The accuracy of the hybrid model was examined by evaluating the stress-dependent prediction model as well as its governing parameters. This investigation uncovers the coupled impact of soil moisture condition and external stress state on the time-dependent performance of grouted anchors embedded in clayey soils by correlating the interface shear strength with soil moisture content and associating the creep model with stress levels applied to the grout–soil interface. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.

语种： 英文

作者： Chen, C.;Zhang, G.*;Zornberg, J. G.;Morsy, A. M.;Huang, J.

期刊： Construction and Building Materials,2020年263:120132 ISSN：0950-0618

通讯作者： Zhang, G.

作者机构： [Chen, C.; Huang, J.] Hunan Univ, Minist Educ, Key Lab Bldg Safety & Energy Efficiency, Changsha 410082, Hunan, Peoples R China.;[Chen, C.; Huang, J.] Hunan Univ, Coll Civil Engn, Changsha 410082, Hunan, Peoples R China.;[Zhang, G.] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Hunan, Peoples R China.;[Zornberg, J. G.] Univ Texas Austin, Dept Civil Architectural & Environm Engn, Austin, TX 78712 USA.;[Morsy, A. M.] Cairo Univ, Dept Civil Engn, Giza 12613, Egypt.

通讯机构： [Zhang, G.] H;Hunan City Univ, Coll Civil Engn, Yiyang 413000, Hunan, Peoples R China.

关键词： Interface bond strength;Bond-slip model;Element pullout test;Glass fiber reinforced polymer reinforcement;Cemented soil

摘要： This paper presents, evaluates, and interprets element pullout tests conducted to investigate the interface bond behavior of Glass Fiber-Reinforced Polymer (GFRP) tendons embedded in cemented soils. Pullout tests were conducted in conjunction with unconfined compression tests to characterize the strength of the cemented soils in which GFRP tendons were embedded. The effects of water content, cement content, and curing time of the cemented soil on the interface bond strength were investigated. Bond-slip curves of the tested specimens were developed considering a multi-segment function defined by characteristic points of interface bond stress peaks and troughs. Two sets of bond-slip curves were identified based on behavior trends observed in the residual strength phase. The ultimate bond strength of the GFRP tendons in cemented soils was found to strongly correlate with the compressive strength of the cemented soil. Ultimately, the bond-slip behavior was modeled using the cemented soil's unconfined compressive strength and the GFRP tendon's rib spacing. The proposed bond-slip model was developed using correlations of bond strength and against the parameters governing the behavior of cemented soil. (C) 2020 Elsevier Ltd. All rights reserved.

语种： 英文

作者： Tang, Huang;Peng, Jianxin*;Zhang, Jianren

期刊： Journal of Performance of Constructed Facilities,2020年34(2) ISSN：0887-3828

通讯作者： Peng, Jianxin

作者机构： [Tang, Huang] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.;[Tang, Huang] Changsha Univ Sci & Technol, Ind Key Lab Transportat Infrastruct Secur Risk Ma, Changsha 410114, Hunan, Peoples R China.;[Peng, Jianxin; Zhang, Jianren] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.

通讯机构： [Peng, Jianxin] C;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.

关键词： Reinforced concrete;Strengthening;Steel plate;Further corrosion;Structural behavior

摘要： This paper presents the results of an experimental study investigating the mechanical behavior of corroded beams strengthened by three different strengthening schemes, and the influence of further corrosion on the structural performance of strengthened corroded beams. Eight rectangular reinforced-concrete (RC) beams were tested through a three-point bending system. The experimental results showed that the failure modes of the strengthened corroded beams were diagonal tensile failure, flexural failure, and support crush failure, respectively. The increases in ultimate load capacity and rigidity of the corroded beams strengthened with combined strengthening were up to 39.44% and 127.57%, respectively, compared with those of the corroded beams. The ductility of the tested beams strengthened with a single U-shaped steel strip was 16.97% greater than that of the corroded beams, while the ductility of the corroded beams strengthened with flexure strengthening and combined strengthening was, respectively, 4.6% and 28.8% lower than that of the corroded beams due to brittle failure. Compared with the strengthened corroded beams, the ductility and ultimate load capacity of all strengthened beams subjected to further corrosion (5% average corrosion loss of the cross section of the tensile steel bar) increased from 53.14% to 73.39% and from 37.37% to 53.13%, respectively. It was found that further corrosion had a small influence on the rigidity of tested beams strengthened by flexure strengthening and combined strengthening as opposed to the beams strengthened by shear strengthening. © 2019 American Society of Civil Engineers.

语种： 英文

作者： Peng, Zhigao*;Liu, Shenggui;Li, Yingjun;Deng, Zongwei;Feng, Haoxiong

期刊： Energies,2020年13(18) ISSN：1996-1073

通讯作者： Peng, Zhigao

作者机构： [Peng, Zhigao; Deng, Zongwei; Feng, Haoxiong] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.;[Peng, Zhigao] Hunan City Univ, Key Lab Key Technol Digital Urban Rural Spatial P, Yiyang 413000, Peoples R China.;[Liu, Shenggui] China Univ Min & Technol Beijing, Sch Mech & Civil Engn, Beijing 100083, Peoples R China.;[Li, Yingjun] China Univ Min & Technol Beijing, State Key Lab Geomech & Deep Underground Engn, Beijing 100083, Peoples R China.

通讯机构： [Peng, Zhigao] H;Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.;Hunan City Univ, Key Lab Key Technol Digital Urban Rural Spatial P, Yiyang 413000, Peoples R China.

关键词： coalbed methane;Lattice Boltzmann method;gas diffusion;adsorption–desorption;pore-scale

摘要： The diffusion–adsorption behavior of methane in coal is an important factor that both affecting the decay rate of gas production and the total gas production capacity. In this paper, we established a pore-scale Lattice Boltzmann (LB) model coupled with fluid flow, gas diffusion, and gas adsorption–desorption in the bi-dispersed porous media of coalbed methane. The Knudsen diffusion and dynamic adsorption–desorption of gas in clusters of coal particles were considered. Firstly, the model was verified by two classical cases. Then, three dimensionless numbers, Re, Pe, and Da, were adopted to discuss the impact of fluid velocity, gas diffusivity, and adsorption/desorption rate on the gas flow–diffusion–adsorption process. The effect of the gas adsorption layer in micropores on the diffusion–adsorption–desorption process was considered, and a Langmuir isotherm adsorption theory-based method was developed to obtain the dynamic diffusion coefficient, which can capture the intermediate process during adsorption/desorption reaches equilibrium. The pore-scale bi-disperse porous media of coal matrix was generated based on the RCP algorithm, and the characteristics of gas diffusion and adsorption in the coal matrix with different Pe, Da, and pore size distribution were discussed. The conclusions were as follows: (1) the influence of fluid velocity on the diffusion–adsorption process of coalbed methane at the pore-scale is very small and can be ignored; the magnitude of the gas diffusivity in macropores affects the spread range of the global gas diffusion and the process of adsorption and determines the position where adsorption takes place preferentially. (2) A larger Fickian diffusion coefficient or greater adsorption constant can effectively enhance the adsorption rate, and the trend of gas concentration- adsorption is closer to the Langmuir isotherm adsorption curve. (3) The gas diffusion–adsorption–desorption process is affected by the adsorption properties of coal: the greater the pL or Vm, the slower the global gas diffusivity decay. (4) The effect of the gas molecular adsorption layer has a great impact on the kinetic process of gas diffusion–adsorption–desorption. Coal is usually tight and has low permeability, so it is difficult to ensure that the gas diffusion and adsorption are sufficient, the direct use of a static isotherm adsorption equation may be incorrect. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

语种： 英文

作者： Feng Haoxiong*;Yi Weijian

期刊： DYNA,2020年95(4):405-411 ISSN：0012-7361

通讯作者： Feng Haoxiong

作者机构： [Feng Haoxiong] Hunan City Univ, Coll Civil Engn, Yingbin East Rd 518, Yiyang 413000, Hunan, Peoples R China.;[Yi Weijian; Feng Haoxiong] Hunan Univ, Coll Civil Engn, Lushan South Rd, Changsha 410082, Hunan, Peoples R China.

通讯机构： [Feng Haoxiong] H;Hunan City Univ, Coll Civil Engn, Yingbin East Rd 518, Yiyang 413000, Hunan, Peoples R China.;Hunan Univ, Coll Civil Engn, Lushan South Rd, Changsha 410082, Hunan, Peoples R China.

关键词： ExpeÂrimental study;Prestressed concrete;Shear bearing;T-beam

摘要： Prestressed concrete t-beams have complex shear mechanism, and their shear performance is influenced by various factors, such as flange width and prestress. The shear performance of prestres-sed concrete t-beams has not been solved completely. This study designed and established nine prestressed concrete t-beams and one ordinary reinforced concrete t-beam to investigate the in-fluence of flange width and the number and bending angle of prestressed tendons on the shear bearing capacity of concrete t-beams. The crack development, failure form, mid-span deflection, and concrete strain of the prestressed concrete t-beams were measured to analyze the load-deflection relationship; the concreÂte strain in the compressive zone; and the shear bearing capacity under different flange widths, reinforcement ratios of prestressed tendons, and bending angles. Experimental results were verified by the outputs of the bearing capacity calculation formula specified in China, America, Canada, and Europe. The results demonstraÂte that the increase in flange width, bending angle, and number of prestressed tendons can improve the internal force and shear bearing capacity of t-beams significantly. However, the flange width has less evident influence on the shear bearing capacity. The positive effect of the flange is evident under a specific flange width. For example, when the ratio of the flange width to the web width is greater than 4. The shear bearing capacity of the presÂtressed concrete t-beams is large when the reinforcement ratio and bending angle of the prestressed tendons are great. This study has reference values for revealing the shear failure mechanism of prestressed concrete t-beams under concentrated loads and proÂvides a basis for engineering design. © 2020 Publicaciones Dyna Sl. All rights reserved.

语种： 英文

作者： Cao, Feng;Zhang, Sheng*;Ling, Tonghua

期刊： Advances in Civil Engineering,2020年2020 ISSN：1687-8086

通讯作者： Zhang, Sheng

作者机构： [Cao, Feng] Survey & Design Inst Co Ltd, Hunan Prov Commun Planning, Changsha 410200, Peoples R China.;[Zhang, Sheng] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.;[Zhang, Sheng] Univ Houston, Dept Mech Engn, Houston, TX 77204 USA.;[Ling, Tonghua] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Peoples R China.

通讯机构： [Zhang, Sheng] H;[Zhang, Sheng] U;Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.;Univ Houston, Dept Mech Engn, Houston, TX 77204 USA.

摘要： Blasting-induced vibration during the excavation of transition section in a branching-out tunnel causes damage and hence affects the safety and stability of the supporting structure and surrounding rock. To examine the effects of excavation and blasting of the transition section in the posterior tunnel on the supporting structures of the anterior tunnel, the influences of the blasting-induced vibration in the posterior tunnel on the anterior tunnel were analyzed under different surrounding rock levels, excavation techniques, distances from explosive source, and net spans. This method was performed by combining numerical simulation with blasting-induced vibration monitoring according to the construction characteristics of the transition section in a branching-out tunnel of a highway. A control technique was investigated to assure the safety and stability of the anterior tunnel during the excavation and blasting of the posterior tunnel. Results demonstrate that (1) the vibration velocity peak behind the blasting excavation surface of the tunnel is higher than that in front. These results suggest paying much attention in monitoring vibration velocity within 10 m behind the excavation surface. (2) The blasting-induced vibration velocity peak on the spandrel at the side that faces the blasting in the anterior tunnel is 2.0-2.5 times than that at the side behind the blasting. Moreover, the blasting-induced vibration velocity peak on the haunch at the side that faces the blasting in the anterior tunnel is 6-7 times than that at the side behind the blasting. (3) Instead of the full-face excavation method, the use of center cross diagram (CRD) technique or side wall pilot tunnel method is suggested for the excavation of surrounding rocks of IV-level, V-level, and III-level with a net span smaller than 3 m. (4) Vibration control measures, such as double wedge-shaped cut blasting and floor blast-hole staged detonation, were adopted by designing and optimizing blasting parameters (e.g., total explosives, maximal segment explosive quantity, detonation order, and detonation interval) in posterior tunnel. According to the test, the blasting-induced vibration velocity peak, which is monitored in the anterior tunnel, can be controlled within 10 cm/s to assure the safety and stability of the supporting structure and surrounding rocks of the tunnel. © 2020 Feng Cao et al.

语种： 英文

作者： Li, Miao;Ren, Wei-Xin*;Huang, Tian-Li;Wang, Ning-Bo

期刊： Journal of Low Frequency Noise Vibration and Active Control,2020年39(3):631-649 ISSN：1461-3484

通讯作者： Ren, Wei-Xin

作者机构： [Li, Miao] Hunan City Univ, Sch Civil Engn, Yiyang, Hunan, Peoples R China.;[Ren, Wei-Xin; Li, Miao] Hefei Univ Technol, Sch Civil Engn, Hefei 230009, Anhui, Peoples R China.;[Huang, Tian-Li; Wang, Ning-Bo] Cent South Univ, Sch Civil Engn, Changsha, Hunan, Peoples R China.

通讯机构： [Ren, Wei-Xin] H;Hefei Univ Technol, Sch Civil Engn, Hefei 230009, Anhui, Peoples R China.

关键词： Damage detection;the varying environmental temperature;dynamic strain;the cross-correlation function amplitude vector;analytical mode decomposition

摘要： This article focuses on the experimental investigations on the cross-correlation function amplitude vector of the dynamic strain (CorV_S) under varying environmental temperature for structural damage detection. It is verified that under white noise excitation, CorV_S is only related to the natural frequencies, mode shapes, and damping ratios of structures. The normalized CorV_S of the undamaged structure maintains a uniform shape. A laboratory experimental investigation based on an end-fixed steel beam shows that CorV_S can be used for structural damage detection. However, CorV_S constructed by the dynamic strain of in-situ test varies with time, and the CorV_S curves do not have the same shape. When the environmental temperature fluctuates significantly, high correlation exists between the dynamic strain and environmental temperature. By analyzing the power spectral density of the signals measured from active and inactive strain gauges, it is found that the signals induced by temperature stress, which do not reflect the dynamic performance of the bridge, exist in the very low-frequency band. To avoid the interference to CorV_S, the temperature effect component is separated from the dynamic strain by analytical mode decomposition method. Then, each CorV_S curve maintains a uniform shape. The results demonstrate that it is prone to get a misjudgment for the condition of a structure if temperature effect on CorV_S is ignored. It is necessary to eliminate the environmental temperature effect on CorV_S for the damage detection of a structure in service. © The Author(s) 2018.

语种： 英文

作者： Peng, Zhigao*;Liu, Shenggui;Li, Yingjun;Yao, Qi

期刊： Geofluids,2020年2020 ISSN：1468-8115

通讯作者： Peng, Zhigao

作者机构： [Yao, Qi; Peng, Zhigao] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.;[Peng, Zhigao] Hunan City Univ, Key Lab Key Technol Digital Urban Rural Spatial P, Yiyang 413000, Peoples R China.;[Liu, Shenggui] China Univ Min & Technol Beijing, Sch Mech & Civil Engn, Beijing 100083, Peoples R China.;[Li, Yingjun] China Univ Min & Technol Beijing, State Key Lab Geomech & Deep Underground Engn, Beijing 100083, Peoples R China.

通讯机构： [Peng, Zhigao] H;Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.;Hunan City Univ, Key Lab Key Technol Digital Urban Rural Spatial P, Yiyang 413000, Peoples R China.

摘要： Methane flow in coal is associated with the content of both organic matter (OM) and inorganic matter (IOM). Coal matrix contains nanopores ranging in size from a few to hundreds of nanometers, which leads to a non-Darcy effect where the measured permeability of a gas (apparent permeability) is higher than that of a liquid (intrinsic permeability). In this study, a generalized Lattice Boltzmann model (GLBM) is employed for gas flow through the reconstructed coal matrix consisting of OM, IOM, and fractures. The apparent permeability model is proposed to calculate the total flow flux accounting for multiple transport mechanisms including viscous flow, slip flow, transitional flow, and the Knudsen diffusion. The impact of effective pore radius and gas surface diffusion on permeability in the gas adsorption-desorption process is also considered in the model. What's more, the weighting factors are adopted to adjust the contribution of the viscous flow and the Knudsen flow. The effect of total organic/inorganic content and the development of fractures on the apparent permeability of the reconstructed coal matrix is also studied. It is found that the apparent permeability is extremely low when a fracture is nonexistent, and varies almost linearly with the total organic/inorganic content. A fracture plays a significant role in determining apparent permeability and the velocity distribution of the coal matrix. © 2020 Zhigao Peng et al.

语种： 英文

作者： Guo, Shihui;Zhang, Yu*;Wang, Ping;Tang, Huang;Dai, Wei;...

期刊： Materials Express,2020年10(9):1404-1411 ISSN：2158-5849

通讯作者： Zhang, Yu;Zhu, Benchao

作者机构： [Guo, Shihui] Nanyang Inst Technol, Sch Civil Engn, Nanyang 473000, Peoples R China.;[Li, Genquan; Zhang, Yu; Wang, Ping] Nanyang Normal Univ, Dept Phys, Nanyang 473061, Peoples R China.;[Tang, Huang] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.;[Dai, Wei] Hubei Univ Educ, Dept Phys & Mech & Elect Engn, Wuhan 430205, Peoples R China.;[Bi, Jie] China Univ Geosci Wuhan, Sch Math & Phys, Wuhan 430074, Peoples R China.

通讯机构： [Zhang, Yu] N;[Zhu, Benchao] H;Nanyang Normal Univ, Dept Phys, Nanyang 473061, Peoples R China.;Hubei Univ Med, Sch Publ Hlth & Management, Shiyan 442000, Peoples R China.

关键词： Density Functional Theory;CALYPSO Structural Prediction;Structural Evolution;Electronic Properties

摘要： We have explored the structural evolution and electronic properties of cationic sodium chloride (NaCl)(n)(+) (n = 1-8) clusters. The global minimum of cationic (NaCl)(n)(+) clusters have been extensively searched using CALYPSO method combined with DFT calculations. The structural evolution of (NaCl)(n)(+) clusters can be divided into three stages: linear structure, planar ring-like structure and three-dimensional structure. It is worth to note that cuboid structure is more common in the cluster series as the cluster size increases. (NaCl)(4)(+) clusters is identified as "magic number" clusters by means of the relative stabilities analyses. The following chemical bonding analysis indicate that the stability of (NaCl)(4)(+) cluster mainly comes from the interaction between Na 3s and CI 3p atomic orbitals.

语种： 英文

作者： He, Ran*;Zhang, Zaihua*;Li, Jingchao

期刊： Advances in Civil Engineering,2020年2020 ISSN：1687-8086

通讯作者： He, Ran;Zhang, Zaihua

作者机构： [Li, Jingchao; Zhang, Zaihua; He, Ran; Zhang, ZH] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Hunan, Peoples R China.

通讯机构： [He, R; Zhang, ZH] H;Hunan City Univ, Coll Civil Engn, Yiyang 413000, Hunan, Peoples R China.

摘要： The prefabricated steel structural residence is characterized by modularization and standardization, which meets the requirement of industrial development. The steel frame beam needs to be fabricated in segments and assembled in site due to the limitation of transportation. In practical engineering, the steel frame beams need to be spliced along the beam span. A robust connection between the two steel beam segments is necessary as it will influence the load bearing capacity, stiffness, and stability of the steel frame. In total, 12 specimens were tested to investigate the influence of spliced types, loading patterns, and bolt types on the performance of the steel frame. The observed failure modes, load versus displacement curves, and moment versus rotation angle curves are presented. The test results show that the strength and deformability of bolt-spliced connections are generally good and similar to those of the prototype beam. © 2020 Ran He et al.

语种： 英文

作者： Cao, Feng;Zhang, Sheng*;Ling, Tonghua

期刊： Shock and Vibration,2020年2020 ISSN：1070-9622

通讯作者： Zhang, Sheng

作者机构： [Cao, Feng] Hunan Prov Commun Planning Survey & Design Inst C, Changsha 410200, Peoples R China.;[Zhang, Sheng] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.;[Zhang, Sheng] Univ Houston, Dept Mech Engn, Houston, TX 77204 USA.;[Ling, Tonghua] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Peoples R China.

通讯机构： [Zhang, Sheng] H;[Zhang, Sheng] U;Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.;Univ Houston, Dept Mech Engn, Houston, TX 77204 USA.

摘要： In blasting excavation of neighborhood tunnels, damage accumulation process in surrounding rock is inevitable. To explore the influence of damage accumulation of rock mass under multiple blasting loads, we analyzed the vibration damage accumulation process of ultrasonic wave velocity of rock mass in shared rock of Liuyuetian neighborhood tunnel through ultrasonic test. Moreover, the effects of cyclic blasting loads on damage to the shared rock in the neighborhood tunnel were discussed and reported. The results demonstrate that the damage accumulation to the shared rock in the neighborhood tunnel is generated after multicycle progressive blasting operations. Influenced by cyclic blasting loads during the posterior excavating tunnel, the damage range of shared rock at the anterior excavating tunnel is 1.2 to 1.4 m, and the damage range of shared rock at the posterior excavating tunnel is 2.2 to 2.4 m. The damage range of shared rock in the posterior excavating tunnel is about 1.71 to 1.83 times that in the anterior excavating tunnel. Under blasting load, the stress concentration zone of shared rock is close to the blasting excavating face and is mainly within 2 m along the longitudinal axis of the tunnel. With continuous advancement of the blasting excavating face, the stress concentration zone moves forward continuously, and a striped stress concentration zone, which is approximately 2 m deep, is formed gradually. Thus, a method was proposed to determine the damage range of shared rock in the neighborhood tunnel during blasting excavation, as well as the variation law of damage. The experiences and conclusions presented can be used as references in the design and construction of similar engineering projects in the future.

语种： 英文

作者： Tang, Huang;Peng, Jianxin*;Xiao, Linfa;Liu, Xinhua;Zhang, Jianren

期刊： Advances in Civil Engineering,2020年2020 ISSN：1687-8086

通讯作者： Peng, Jianxin

作者机构： [Tang, Huang] Hunan City Univ, Sch Civil Engn, Yingyang 413000, Hunan, Peoples R China.;[Tang, Huang] Changsha Univ Sci & Technol, Ind Key Lab Transportat Infrastruct Secur Risk Ma, Changsha 410114, Peoples R China.;[Xiao, Linfa; Peng, Jianxin; Zhang, Jianren; Liu, Xinhua] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Peoples R China.

通讯机构： [Peng, Jianxin] C;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Peoples R China.

摘要： This paper proposes 3D nonlinear finite element (FE) models to predict the response of corroded reinforced concrete (RC) beam strengthened using a steel plate. Five FE models are developed based on the tests carried out by the authors in a previous investigation, in which three models are used to simulate the corroded RC beams with different schemes. The FE models use the coupled damaged-plasticity constitutive law for concrete in tension and compression and consider the bond-slip between the corroded tensile steel bar and concrete. The cohesive element is also used to model the cohesive bond between the steel plate and concrete. The FE results of load-deflection and the crack distribution are compared with the test data. The FE results are consistent with the test results. The influence of the thickness of the steel plate, the thickness, and location of the U-shaped steel strip on the bearing capacity of the strengthened corroded beam is analyzed through FE models. The results show that the thickness of the steel plate on the bottom surface should not exceed 4 mm for the flexure-strengthened and combined strengthened beams with a 10% corrosion rate. It is most reasonable to improve the bearing capacity using the 3 mm and 2 mm of thick U-shaped steel strips for the shear-strengthened and combined strengthened beams, respectively. The most reasonable location of the U-shaped steel plate is at the end of the steel plate for beams with a 10% corrosion rate. © 2020 Huang Tang et al.

语种： 英文

作者： Feng, Haoxiong;Yi, Weijian*

期刊： Fresenius Environmental Bulletin,2020年29(6):4464-4472 ISSN：1018-4619

通讯作者： Yi, Weijian

作者机构： [Yi, Weijian; Feng, Haoxiong] Hunan Univ, Coll Civil Engn, Changsha, Peoples R China.;[Feng, Haoxiong] Hunan City Univ, Sch Civil Engn, Yiyang, Peoples R China.

通讯机构： [Yi, Weijian] H;Hunan Univ, Coll Civil Engn, Changsha, Peoples R China.

关键词： Experiment;Prestressed Concrete;Shear Mechanism;Tbeams

摘要： The technology of prestressed concrete is widely used in structures, prestressed concrete t-beams have complex shear mechanism which is influenced by various factors and not been solved completely. In order to study the influence of flange width, number and bent-up angle of prestressed tendons on the shear bearing capacity of concrete t-beams, nine prestressed concrete t-beams and one ordinary reinforced concrete t-beam were designed and manufactured. The crack development, failure pattern, mid-span deflection, concrete strain, stirrup strain and crack width of prestressed concrete tbeams were measured and analyzed. The results showed that the internal force and shear bearing capacity of t-beams can be increased by changing the flange width and the level of prestress force, and improved the shear mechanism. This study has a reference value to reveal the shear failure mechanism of prestressed concrete t-beam under concentrated load. © by PSP.

语种： 英文

作者： Ling, Tong-hua;Zhang, Liang*;Huang, Fu;Gu, Dan-ping;Yu, Bin;...

期刊： 中南大学学报(英文版),2019年26(11):3057-3065 ISSN：2095-2899

通讯作者： Zhang, Liang

作者机构： [Zhang, Liang; Gu, Dan-ping; Huang, Fu; Yu, Bin; Ling, Tong-hua] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Peoples R China.;[Zhang, Liang] Changsha Univ Sci & Technol, Hunan Prov Engn Lab Bridge Struct, Changsha 410114, Peoples R China.;[Zhang, Sheng] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.

通讯机构： [Zhang, Liang] C;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Peoples R China.;Changsha Univ Sci & Technol, Hunan Prov Engn Lab Bridge Struct, Changsha 410114, Peoples R China.

关键词： orthogonal matching pursuit;Hilbert transform;shield tunnel;lining structure;hidden micro-crack

摘要： In the light of the problem of weak reflection signals shielded by strong reflections from the concrete surface, the detection and the recognition of hidden micro-cracks in the shield tunnel lining were studied using the orthogonal matching pursuit and the Hilbert transform(OMHT method). First, according to the matching pursuit algorithm and the strong reflection-forming mechanism, and based on the sparse representation theory, a sparse dictionary, adapted to the characteristics of the strong reflection signal, was selected, and a matching decomposition of each signal was performed so that the weak target signal submerged in the strong reflection was displayed more strongly. Second, the Hilbert transform was used to extract multiple parameters, such as the instantaneous amplitude, the instantaneous frequency, and the instantaneous phase, from the processed signal, and the ground penetrating radar (GPR) image was comprehensively analyzed and determined from multiple angles. The results show that the OMHT method can accurately weaken the effect of the strong impedance interface and effectively enhance the weak reflected signal energy of hidden micro-crack in the shield tunnel segment. The resolution of the processed GPR image is greatly improved, and the reflected signal of the hidden micro-crack is easily visible, which proves the validity and accuracy of the analysis method.

语种： 英文

作者： Shu, Xingping;He, Ran*;Zhang, Zaihua;Yao, Yao;Leonard, J.

期刊： DYNA,2019年94(2):189-196 ISSN：0012-7361

通讯作者： He, Ran

作者机构： [Shu, Xingping; Yao, Yao; He, Ran] Hunan Univ, Steel Struct Inst, Civil Engn Coll, Changsha 410082, Hunan, Peoples R China.;[Zhang, Zaihua; He, Ran] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.;[Leonard, J.] Northwestern Univ, Dept Civil & Environm Engn, 2145 Sheridan Rd, Evanston, IL 60208 USA.

通讯机构： [He, Ran] H;Hunan Univ, Steel Struct Inst, Civil Engn Coll, Changsha 410082, Hunan, Peoples R China.;Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.

关键词： Assembling slab seam;In-plane stiffness;Integrality of floor;Prefabricated composite floor;Rigid floor;Semi-rigid floor;Truss composite floor system

摘要： Horizontal load is the main controlling factor of high-rise prefabricated structure and floor system is a fundamental part that ensures the effective transmission of horizontal load in the structural system. However, the mechanical properties of traditional prefabricated systems including wooden floor and concrete floor are poor. Thus, neither of them is suitable for long-span prefabricated structures. In order to improve the mechanical properties of floor systems, a new truss composite floor composed of four factory-made floor units and assembled by bolts on site that could be applied to the long-span prefabricated structure was proposed in this study. In-plane unidirectional loading tests were performed on 4 two-story frame structural models in order to study the response of the different parameters involved in the proposed floor system. Taking the second floor of each model as the analysis object, the in-plane failure characteristics, deformation, equivalent shear stiffness were analyzed. At last, the integrality and in-plane stiffness of the new floor were also evaluated further. Test results indicate that all of the cracking loads of concrete slab in the new floor system are greater than the equivalent horizontal force of floor that is stipulated by China code in case of 7-degree rare earthquake. In addition, the reinforcement measures (e.g. pouring structural adhesives into the major slab seam and setting a post-cast stripe between floor and frame beam) can improve the mechanical properties of the new floor system greatly. The distribution pattern of cracks on concrete slab evolves from irregular local dotted distribution into significant linear distribution, which indicates that the integrality of the floor system gets strengthened greatly. More specifically, the inplane equivalent shear stiffness of the floor is 3.4-5.3 times that of the previous one in which the reinforcement measures are not taken, at the same time, the overall lateral stiffness of the floor system is increased by 2 times, which means that the in-plane rigidity is significantly enhanced after taking the reinforcement measures. That's to say, the floor is transformed from a semi-rigid floor to a rigid floor. Therefore, the experimental study can provide the reference for the popularization and application of the proposed prefabricated truss composite floor system. © 2019 Publicaciones Dyna Sl. All rights reserved.

语种： 英文

作者： Liu, Jing;Wang, Wen-jun*;Ding, Fa-xing*;Zeng, Xin-fa;Tan, Zhe;...

期刊： Advances in Civil Engineering,2019年2019 ISSN：1687-8086

通讯作者： Wang, Wen-jun;Ding, Fa-xing

作者机构： [Wang, Wen-jun; Liu, Jing; Ding, Fa-xing; Wang, WJ] Cent S Univ, Sch Civil Engn, Changsha 410075, Hunan, Peoples R China.;[Tan, Zhe; Liu, Jing; Zeng, Xin-fa; Huang, Yan; Wang, Bao-quan] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.

通讯机构： [Wang, WJ; Ding, FX] C;Cent S Univ, Sch Civil Engn, Changsha 410075, Hunan, Peoples R China.

摘要： This article presents the experimental and finite element (FE) analyses of two conventional rectangular concrete-filled steel tubular (CFT) stub columns, two stiffened rectangular concrete-filled steel tubular (SCFT) stub columns, and two stirrup confinement rectangular concrete-filled steel tubular (CCFT) stub columns concentrically loaded in compression to failure. The influences of the ductility and ultimate bearing strength of these stub columns with stiffening ribs or spiral stirrup confinement were discussed. Abaqus was used to establish a 3D FE model and analyze the properties of CFT stub columns subjected to axial compression. The effect of the concrete core and rectangular steel tube under loop stirrup confinement was discussed. Analytical results showed that spiral stirrup confinement can availably retard the local bucking of the rectangular steel pipe, and the effect of the spiral stirrup confinement was stronger than that of stiffeners. The DI values of SCFT and CCFT were 21.9% and 31.9% larger than those of CFT, respectively. The ultimate capacity values of SCFT and CCFT were 10.2% and 18% larger than those of CFT, respectively. The ductility and ultimate bearing strength of the specimens improved effectively under spiral stirrup confinement, and the ductility of the CCFT columns was preferable to that of the SCFT columns. © 2019 Jing Liu et al.

语种： 英文

作者： Wei, Jing;Zeng, Xin-fa*

期刊： Cluster Computing,2019年22(3):7577-7583 ISSN：1386-7857

通讯作者： Zeng, Xin-fa

作者机构： [Wei, Jing] China Univ Min & Technol, Sch Environm Sci & Spatial Informat, Xuzhou 221116, Jiangsu, Peoples R China.;[Wei, Jing] Jiangsu Vocat Inst Architectural Technol, Coll Construct Management, Xuzhou 221116, Jiangsu, Peoples R China.;[Zeng, Xin-fa] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Hunan, Peoples R China.

通讯机构： [Zeng, Xin-fa] H;Hunan City Univ, Coll Civil Engn, Yiyang 413000, Hunan, Peoples R China.

关键词： Cloud computing;Computing resource allocation;Scheduling;Singular value decomposition;Data clustering;Hybrid differential parallel scheduling

摘要： In order to improve the ability of resource allocation and scheduling in cloud computing, optimize resource allocation and improve the efficiency of cloud computing, an optimal computing resource allocation algorithm in cloud computing based on hybrid differential parallel scheduling is proposed. In this algorithm, the models of data structure and gird structure of computing resource allocation in cloud computing are constructed, and the sample clustering analysis method of resource information flow is used to classify the attributes of computing resources; the sliding window of computing resource allocation is divided into multiple sub-windows; characteristic quantities associated with computing resource allocation attributes are selected in neighbor samples as standard vector sets for adaptive pairing; the computing resources in cloud computing are done with singular value decomposition and the resource allocation is transformed into the least square problem; the hybrid differential parallel computing method is used for optimal solution finding of resource scheduling vector set to prevent the allocation results from falling into local optimal solution, so as to improve the global convergence of resource allocation. The simulation results show that when the method proposed in this paper is used for resource allocation in clouding computing, the clustering performance is high and the convergence control ability to computing resources with different attributes is high; the allocation speedup can reach 3.67, which is improved by 14.65 and 7.43% respectively compared with that in the traditional HEFT algorithm and HCNF algorithm; when the number of allocate nodes is 100, the overhead is only 5.6, which is reduced by 14.56 and 8.33% than that in traditional HEFT algorithm and HCNF algorithm. So it shows that the proposed method has a higher practical application performance for its shorter execution time and lower overhead.

语种： 英文

作者： Liu, Jing;Ding, Fa-xing*;Liu, Xue-mei;Yu, Zhi-wu;Tan, Zhe;...

期刊： Advances in Civil Engineering,2019年2019 ISSN：1687-8086

通讯作者： Ding, Fa-xing

作者机构： [Liu, Jing; Yu, Zhi-wu; Ding, Fa-xing] Cent South Univ, Sch Civil Engn, Changsha 410075, Hunan, Peoples R China.;[Huang, Jun-wen; Tan, Zhe; Liu, Jing] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.;[Ding, Fa-xing] Engn Technol Res Ctr Prefabricated Construct Ind, Changsha 410075, Hunan, Peoples R China.;[Liu, Xue-mei] Univ Melbourne, Dept Infrastruct Engn, Parkville, Vic 3010, Australia.

通讯机构： [Ding, Fa-xing] C;[Ding, Fa-xing] E;Cent South Univ, Sch Civil Engn, Changsha 410075, Hunan, Peoples R China.;Engn Technol Res Ctr Prefabricated Construct Ind, Changsha 410075, Hunan, Peoples R China.

摘要： This study investigates the flexural strength of simply supported steel-concrete composite beams under hogging moment. A total of 24 composite beams are included in the experiments, and ABAQUS software is used to establish finite element (FE) models that can simulate the mechanical properties of composite beams. In a parametric study, the influences of several major parameters, such as shear connection degree, stud arrangement and diameter, longitudinal and transverse reinforcement ratios, loading manner, and beam length, on flexural strength were investigated. Thereafter, three standards, namely, GB 50017, Eurocode 4, and BS 5950, were used to estimate the flexural strength of the composite beams. These codes were also compared with experimental and numerical results. Results indicate that GB 50017 may provide better estimations than the other two codes. © 2019 Jing Liu et al.

语种： 英文

作者： Liu, Jing;Li, Zhe*;Ding, Fa-Xing*

期刊： Advances in Civil Engineering,2019年2019 ISSN：1687-8086

通讯作者： Ding, Fa-Xing;Li, Zhe

作者机构： [Liu, Jing] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.;[Liu, Jing; Ding, Fa-Xing] Cent S Univ, Sch Civil Engn, Changsha 410075, Hunan, Peoples R China.;[Li, Zhe] Cent S Univ, Sch Architecture & Art, Changsha 410075, Hunan, Peoples R China.

通讯机构： [Ding, Fa-Xing; Li, Zhe] C;Cent S Univ, Sch Civil Engn, Changsha 410075, Hunan, Peoples R China.;Cent S Univ, Sch Architecture & Art, Changsha 410075, Hunan, Peoples R China.

摘要： This study aimed to investigate the static performance of notched hexagonal concrete-filled steel tube (CFST) stub columns through axial loading. Notch length, notch location, and notch direction in 14 CFST stub columns were experimentally studied. Stress process, failure mechanism, and ultimate strength in the notched CFST columns were analyzed. Results show that notches in steel tubes can weaken the restraining effect of steel pipes on core concrete and induce a decrease in the ultimate strength of specimens. The failure mode of components is greatly affected by notch orientation. The notch is closed under axial compression in the horizontally notched specimen, and the slotting indicates outward buckling in the vertically notched specimen. Based on the test results, a method for calculating the ultimate strength of notched hexagonal CFST columns was established. This research encourages the extensive application of these structures in civil engineering. © 2019 Jing Liu et al.

语种： 英文

作者： Wang, Xinzhong;He, Jun*;Mosallam, Ayman S.;Li, Chuanxi;Xin, Haohui*

期刊： Advances in Materials Science and Engineering,2019年2019 ISSN：1687-8434

通讯作者： He, Jun;Xin, Haohui

作者机构： [Wang, Xinzhong] Hunan City Univ, Sch Civil Engn, Yiyang, Peoples R China.;[He, Jun; Li, Chuanxi] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha, Hunan, Peoples R China.;[He, Jun] Heriot Watt Univ, Inst Infrastruct & Environm, Edinburgh, Midlothian, Scotland.;[Mosallam, Ayman S.] Univ Calif Irvine, Dept Civil & Environm Engn, Irvine, CA USA.;[Xin, Haohui] Delft Univ & Technol, Civil Engn & Geosci, Delft, Netherlands.

通讯机构： [He, Jun] C;[He, Jun] H;[Xin, Haohui] D;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha, Hunan, Peoples R China.;Heriot Watt Univ, Inst Infrastruct & Environm, Edinburgh, Midlothian, Scotland.

摘要： Basalt fiber reinforced concrete (BFRC) has been widely utilized in various constructions such as buildings, large industrial floors, and highways, due to its excellent physical and mechanical properties, as well as low production cost. In order to address the influence of basic parameters such as fiber volume fraction (0.05∼0.40%), fiber length (12∼36 mm) of BF, and compressive strength (30, 40, and 50 MPa) of concrete on both physical and mechanical properties of BFRC including compressive strength, tensile and flexural strength, workability, and anti-dry-shrinkage cracking properties, a series of standard material tests were conducted. Experimental results indicated that clumping of fibers may occur at relatively higher fiber volume fraction resulting in mixing and casting problems. Based on experimental values of mechanical properties and anti-dry-shrinkage cracking resistance of BFRC, the reasonable basalt fiber length and fiber volume fractions are identified. The addition of a small amount of short basalt fibers can result in a considerable increase in both compressive strength and modulus of rupture (MoR) of BFRC and that the proposed fiber length and content are 12.0 mm and 0.10%∼0.15%, respectively. As the length of basalt fibers increases, the development of early shrinkage cracks decreases initially and then increases slowly and the optimal fiber length is 18.0 mm. Results of the study also indicated that early shrinkage cracks decrease with the increase of fiber volume fraction, and when the volume fraction of 0.20% is used, no cracks were observed. All the findings of the present study may provide reference for the material proportion design of BFRC. © 2019 Xinzhong Wang et al.

语种： 英文