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Development and Application of a High-Volume Recycled Powder Solidifying Material for Waterworks Sludge

Journal of Renewable Materials 2022年第4期10卷 939-953页

作者： Xiang Deng Sudong Hua Fan Xia Yanfang Zhang Dapeng Guo Xinxing Zhu Defei Zhu co.lege of Materials Science and Engineering Nanjing Tech UniversityNanjing211816China China construction Installation group nanjing construction co. Ltd.Nanjing210023China nanjing Pukou urban and Rural construction group co. Ltd.Nanjing211800China

Recycled powder(RP)is produced as a by-product during the process of recycling construction and demolition(C&D)wastes,presenting a low additional *** RP-based solidifying material can not only improve its utilization efficiency,but also reduce the co.t of co.mercial solidifying *** date,this is the best solidifying material utilized to dispose the original waterworks sludge(OWS)with high moisture co.tents(60%),and the product co.ld be used to fabricate non-fired *** has beco.e a new environment-friendly technology of“using waste to treat waste”.In this paper,the influence of different particle sizes and dosages of RP on the prepared solidifying material was ***,unco.fined co.pression strength(UCS),volume stability,chemical co.position,and heat of hydration,pore structure of the solidifying material were ***,non-fired bricks were prepared by using the solidifying material,recycled aggregate,and original waterworks *** UCS and softing co.fficient(SC)of the non-fired bricks were *** a result,the 28-day UCS of the solidifying material with optimal(M30)was 35.40 MPa,which co.ld reach 84.37%of Portland cement(PC).The addition of RP increased the volume stability of the solidifying *** addition of a large amount of RP reduced the heat flux and cumulative heat release of the solidifying material,while its porosity *** UCS of non-fired brick(NF20)in 28 days was 15.19 MPa and the SC after 28 days was 78.35%.In co.clusion,the preparation of solidifying material using RP co.ld be a promising approach and has a great potential in disposal of original waterworks sludge.

关键词： Recycled powder solidifying material original waterworks sludge non-fired brick unco.fined co.pressive strength

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Fractal-based weak target detection within sea clutter

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Acta Oceanologica Sinica 2014年第9期33卷 68-72页

作者： LI Yang LV Xiaowen LIU Kuisheng ZHAO Shangzhuo China Academy of Electronics and Information Technology Beijing urban Engineering Design & Research Institute co. LTD Beijing urban construction group co. Ltd. School of Marine Sciences Nanjing University of Information Science and Technology

The target on the sea surface is co.plex and difficult to detect due to the interference of backscattered returns from the sea surface illuminated by the radar pulse. Detrended fluctuation analysis （DFA） has been used successfully to extract the time-domain Hurst exponent of sea-clutter series. Since the frequency of the sea clutter mainly co.centrates around Doppler center so that we co.sider to extract frequency-do- main fractal characterization and then detect a weak target within sea clutter by using the difference of frequency-domain fractal characterization. The generalized detrended fluctuation analysis （GDFA） is more flexible than traditional DFA owing to its smoothing action for the clutters. In this paper, we apply the GDFA to evaluate the generalized Hurst exponent of sea-clutter series in the frequency domain. The difference of generalized Hurst exponents between different sea-clutter range bins would be used to determine whether the target exists. Moreover, some simulations with the real IPIX radar data have also been demonstrated in order to suooort this co.clusion.

关键词： sea clutter weak target detection generalized detrended fluctuation analysis

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Mechanical properties and energy evolution of Beishan shallow-layer granite under different unloading paths

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Journal of Mountain Science 2024年第5期21卷 1728-1744页

作者： WANG Chuanle LI Erbing ZHANG Dengke HAN Yang LU Hui HE Kang DU Guangyin School of Transportation Southeast UniversityNanjing 211189China co.lege of Defense Engineering Army Engineering University of PLANanjing 210007China nanjing urban construction management group co. Ltd.Nanjing 210006China co.lege of Field Engineering Army Engineering University of PLANanjing 210007China

Rock has mechanical characteristics and a fracture damage mechanism that are closely related to its loading history and loading path. The mechanical properties, fracture damage features, aco.stic emission(AE) characteristics, and strain energy evolution of the Beishan shallow-layer granite used in triaxial unloading tests were investigated in this study. Three groups of triaxial tests, namely, co.ventional triaxial co.pression test(group Ⅰ), maintaining deviatoric stress synchronously unloading co.fining pressure test(group Ⅱ), and loading axial pressure synchronously unloading co.fining pressure test(group Ⅲ), were carried out for the cylindrical granite specimens. AE monitoring device was utilized in these tests to determine the degree to which the AE waves and AE events reflected the degree of rock damage. In addition, the crack stress thresholds of the specimens were determined by volumetric strain method and AE parameter method, and strain energy evolution of the rock was explored in different damage stages. The results show that the shallow-layer granite experiences brittle failure during the triaxial loading test and unloading test, and the rock has a greater damage degree during the unloading test. The crack stress thresholds of these samples vary greatly between tests, but the threshold ratios of all samples are similar in the same crack damage stage. The Mogi-co.lomb strength criterion can better describe the unloading failure strength of the rock. The evolution of the AE parameter characteristics and strain energy differs between the specimens used in different stress path tests. The dissipative strain energy is the largest in group Ⅱ and the smallest in group Ⅰ.

关键词： Beishan granite Unloading test Mechanical properties Damage mechanism Aco.stic emission Strain energy

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Uplift mechanism for a shallow-buried structure in liquefi able sand subjected to seismic load: centrifuge model test and DEM modeling

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Earthquake Engineering and Engineering Vibration 2014年第2期13卷 203-214页

作者： Zhou Jian Wang Zihan Chen Xiaoliang Zhang Jiao Department of Geotechnical Engineering Tongji University School of Civil Engineering Hebei University of Technology Hangzhou Municipal construction group co. LTD School of Civil Engineering and Transportation Shanghai Technical College of Urban Management

Based on a centrifuge model test and distinct element method(DEM), this study provides new insights into the uplift response of a shallow-buried structure and the liquefaction mechanism for saturated sand around the structure under seismic action. In the centrifuge test, a high-speed microsco.ic camera was installed in the structure model, by which the movements of particles around the structure were monitored. Then, a two-dimensional digital image processing technology was used to analyze the microstructure of saturated sand during the shaking event. Herein, a numerical simulation of the centrifuge experiment was co.ducted using a two-phase(solid and fl uid) fully co.pled distinct element co.e. This co.e inco.porates a particle-fl uid co.pling model by means of a "fi xed co.rse-grid" fl uid scheme in PFC3D(Particle Flow co.e in Three Dimensions), with the modeling parameters partially calibrated based on earlier studies. The physical and numerical models both indicate the uplifts of the shallow-buried structure and the sharp rise in excess pore pressure. The co.responding micro-scale responses and explanations are provided. Overall, the uplift response of an underground structure and the occurrence of liquefaction in saturated sand are predicted successfully by DEM modeling. However, the dynamic responses during the shaking cannot be modeled accurately due to the restricted co.puter power.

关键词： centrifuge modeling underground structure liquefaction distinct element method saturated sand

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Research on the basic theoretical issues of smart metro construction

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Science China(Technological Sciences) 2019年第11期62卷 2038-2051页

作者： WEI Yun HUANG Wei CAO JinDe BAI WenFei TONG ShuZhen National Engineering Laboratory for Green&Safe construction Technology in urban Rail Transit Beijing 10037China Beijing urban construction Design&Development group co. LimitedBeijing 100037China Jiangsu Provincial Key Laboratory of Networked co.lective Intelligence ITS Research CenterSoutheast UniversityNanjing 210096China

The basic co.ception and theoretical system of smart metro are not clear and there is not a unified understanding at the academic *** on this fact,there is no guidance of the smart metro ***,this paper co.ducts a co.plete and systemic research on several basic theoretical issues of smart metro,such as the development history,co.cept,co.notation,characteristics,evolution stages,system architecture and main construction ***,the internal and external development demands are analyzed in this *** addition,the subject-cycle-function(SCF)model of smart metro co.cept is ***,the essential co.notation,three typical characteristics and the evolution process of smart metro are ***,the evolution relationships of main function,achievement goal,instrument subject,decision subject,co.trol subject and factor relationship for every evolution stage are ***,acco.ding to the theory of system engineering,the three-hierarchy system architecture and five main construction co.tents are *** both can be used to co.struct the technical system of smart metro at the academic level,and provide theoretical support and technical guidance for promoting the development of smart metro construction in China.

关键词： smart metro basic theory issues system architecture

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Development of Steel Slag-Based Solidification/Stabilization Materials for High Moisture co.tent Soil

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Journal of Renewable Materials 2022年第3期10卷 735-749页

作者： Yu Jia Sudong Hua Liying Qian Xiaojian Ren Jie Zuo Yanfang Zhang co.lege of Materials Science and Engineering Nanjing Tech UniversityNanjing210009China Jangsu Yonggang group co. Ltd.Suzhou215628China China construction Installaction Engineering co. Ltd.Nanjing210023China

To solve the problems of high moisture co.tent,high visco.ity,and poor engineering mechanical properties of soil,this paper using with steel slag(SS)and desulfurization ash(DS)as initial raw materials,realizing the co.p-erative treatment of solid waste and solidification of silt *** synergistic utilization of SS and DS can reduce the production co.t of curing agent and promote its own *** to blended cement of various SS co.tents and inspected co.pressive strength performances,the most suitable raw materials ratio was *** best formula for this curing agent is cement:steel slag=3:7 with 5%DS,and its 28-day co.pressive strength can reach 30 *** experiment shows that the effect of DS and Na_(2)SO_(4) reagent with the same quality on early co.pressive strength improvement of cement and SS system is not much *** this study,the mineral co.position and microstructure of different gel system blocks were characterized by XRD,SEM and EDX,and a large number of webbed structures were found in the SEM test,which was not seen in previous ***,unco.fined co.pressive strength(UCS),water resistance,and toxic characteristic leaching procedure(TCLP)were used to evaluate silt solidified soil *** results demonstrated that the solidified silt co.ld meet not only the standard of general subgrade;but also has a partial stabilization effect of heavy metal ions.

关键词： Steel slag desulfurization ash high moisture co.tent soil synergistic effect strength stabilized soil

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Development of a Soil Stabilizer for Road Subgrade Based on Original Phosphogypsum

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Journal of Renewable Materials 2021年第2期9卷 253-268页

作者： Zenghuan Gu Aiguo Fang Sudong Hua Qingzhou Zhao Lidong Sun Fan Xia Liying Qian Xiaojian Ren co.lege of Materials Science and Engineering Nanjing Tech UniversityNanjing210009China China construction Installation Engineering co. Ltd.Nanjing210023China Jiangsu YongGang group co. Ltd.Suzhou215628China

The research used industrial by-products original phosphogypsum(PG)as the main raw material,slag(SG)and Portland cement(PC)as auxiliary materials,and the optimal additive amount was determined acco.ding to the co.pressive strength value of the *** evaluate the water resistance and volume stability of the samples,and determine the best formula for new roadbed stabilized *** results showed that when the weight ratio of PG,slag and cement was OPG:SG:PC=6:3:1,and mixed with 5%micro silica fume(MSF)and 3‰hydroxypropyl methyl cellulose(HPMC),the sample’s co.prehensive performance was the best,specifically,the sample’s co.pressive strength in 60 days reached 28.8 MPa,the softening co.fficient reached 0.9,and the expansion rate was stable at about−0.2%.In addition,the mechanism of action of enhancers MSF and HPMC was analyzed acco.ding to use Vicat device,X-ray diffractometer and scanning electron *** best formula SP3GH3 has the best curing effect on *** 28-day unco.fined co.pressive strength(UCS)of the sample reached 2.4 MPa,the expansion rate was less than 0.09%,and the water stability co.fficient was above 0.79,which was higher than that of the samples cured by traditional cement and lime during the same period.

关键词： Original phosphogypsum subgrade stabilized material co.pressive strength softening co.fficient expansion rate

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Analysis of the Relationship between Mechanical Properties and Pore Structure of MSW Incineration Bottom Ash Fine Aggregate co.crete after Freeze-Thaw Cycles Based on the Gray Theory

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Journal of Renewable Materials 2023年第2期11卷 669-688页

作者： Peng Zhang Dongsheng Shi Ping Han Wenchao Jiang School of Civil Engineering Inner Mongolia University of TechnologyHohhot010000China Xingtai construction group co. Ltd.Hohhot010000China Inner Mongolia Electric Power(group)co.pany Limited Mengdian Project construction and management Branch Hohhot010000China

The destruction of co.crete building materials in severely co.d regions of the north is more severely affected by freeze-thaw cycles,and the relationship between the mechanical properties and pore structure of co.crete with fine aggregate from municipal solid waste(MSW)incineration bottom ash after freeze-thaw cycles is analyzed under the degree of freeze-thaw hazard *** this paper,the gray co.relation method is used to calculate the co.relation between the relative dynamic elastic modulus,co.pressive strength,and microsco.ic porosity parameters to speculate on the most important factors affecting their *** GM(1,1)model was established based on the co.pressive strength of the waste incineration ash aggregate co.crete,the relative error between the simulated and actual values in the model was less than 5%,and the accuracy of the model was level 1,indicating that the GM(1,1)model can well reflect the change in the co.pressive strength of the MSW incineration bottom ash aggregate co.crete during freeze-thaw *** the gray co.relation method,the co.relation between the relative dynamic elastic modulus,co.pressive strength,air co.tent,specific surface area,pore spacing co.fficient,and pore average chord length was calculated,and the pore spacing co.fficient and pore average chord length were determined to be highly co.related with each *** determination can help analyze and infer the deterioration mechanism of co.crete subject to freeze-thaw *** results can provide a theoretical basis for guiding the engineering practice of co.crete with fine aggregates of household bottom ash in the northern co.d region.

关键词： Municipal solid waste incineration bottom ash co.crete gray system theory mechanical properties pore structure

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Regression Method for Rail Fastener Tightness Based on Center-Line Projection Distance Feature and Neural Network

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 356-371页

作者： Yuanhang Wang Duxin Liu Sheng Guo Yifan Wu Jing Liu Wei Li Hongjie Wang Robotics Research Center School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China China construction Industrial&Energy Engineering group co. Ltd.Nanjing 210023China

In the railway system,fasteners have the functions of damping,maintaining the track distance,and adjusting the track ***,routine maintenance and inspection of fasteners are important to ensure the safe operation of track ***,assessment methods for fastener tightness include manual observation,aco.stic wave detection,and image *** are limitations such as low accuracy and efficiency,easy interference and misjudgment,and a lack of accurate,stable,and fast detection *** at the small deformation characteristics and large elastic change of fasteners from full loosening to full tightening,this study proposes high-precision surface-structured light technology for fastener detection and fastener deformation feature extraction based on the center-line projection distance and a fastener tightness regression method based on neural ***,the method uses a 3D camera to obtain a fastener point cloud and then segments the elastic rod area based on the iterative closest point algorithm *** co.ponent analysis is used to calculate the normal vector of the segmented elastic rod surface and extract the point on the centerline of the elastic *** point is projected onto the upper surface of the bolt to calculate the projection ***,the mapping relationship between the projection distance sequence and fastener tightness is established,and the influence of each parameter on the fastener tightness prediction is ***,by setting up a fastener detection scene in the track experimental base,co.lecting data,and co.pleting the algorithm verification,the results showed that the deviation between the fastener tightness regression value obtained after the algorithm processing and the actual measured value RMSE was 0.2196 mm,which significantly improved the effect co.pared with other tightness detection methods,and realized an effective fastener tightness regression.

关键词： Railway system Fasteners Tightness inspection Neural network regression 3D point cloud processing

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Piezoelectric sensing method for segmental joint co.tact stress during shield tunnel construction

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Underground Space 2024年第4期17卷 82-99页

作者： Guodong Jiang Minghao Dai Guozhu Zhang Limin Gao Institute of Geotechnical Engineering Southeast UniversityNanjing 211189China nanjing Metro group co.Ltd Nanjing 210000China No.4 construction co.pany of China Petroleum Pipeline Engineering co.Ltd Langfang 065000China

The emergence of curved shield tunnels poses a significant construction *** the quality of the segment assembly is not guaranteed,many segment cracks and damage will result from the stress *** the co.tact stresses between segmental joints is necessary to improve the quality of segments assembled for shield tunnel *** difluoride(PVDF)piezoelectric material was chosen for the sensor because it can co.vert co.tact stresses into electrical signals,allowing the state of the segmental joints to be effectively *** matches the working environment between the segmental joints of the shield tunnel,where flexible structures such as rubber gaskets and force transfer pads are *** study proposes a piezoelectric sensing method for segmental joints in shield tunnels and co.ducts laboratory tests,numerical analyses,and field tests to validate the feasibility of the *** results indicate that the PVDF film sensor can effectively sense the entire co.pression process of the gasket with different amounts of *** piezoelectric cable sensor can effectively sense the joint offset direction of the *** differently shaped sections,the variation in the force sensed by the piezoelectric cable sensors was different,as verified by numerical *** the field test,it was found that the average co.tact stress between the segmental joints was in the range of 1.2–1.8 MPa during construction of the curved shield *** location of the segmental joints and the type of segment affect the co.tact stress *** field monitoring results show that piezoelectric sensing technology can be successfully applied during assembly of the segments for effective sensing of the co.tact stress.

关键词： Shield tunnel Segmental joint co.tact stress Piezoelectric sensor

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