In situ recycling is one of the most effective methods to dispose of earth pressure balance(EPB)shield waste muck with residual foaming agents with high moisture content.In this context,response surface methodology(RS...In situ recycling is one of the most effective methods to dispose of earth pressure balance(EPB)shield waste muck with residual foaming agents with high moisture content.In this context,response surface methodology(RSM)was employed to quantify the effects of independent variables,including flocculant dosage,defoamer dosage,and muck drying mass(MDM)and their interactions on defoaming-flocculation-dewatering indices.The polymeric aluminum chloride(PACL)and hydroxy silicone oil-glycerol polypropylene ether(H-G)were selected as the flocculant and defoamer.The contents of surfactants and foam stabilizers in residual foaming agents were determined using the proposed empirical equation.The defoaming ratio,antifoaming ratio,turbidity,moisture content,filtration loss ratio,and fall cone penetration depth were considered as dependent variables.The accuracy of developed RSM models was verified by the analysis results of variance,residuals,and paired t-test.Combined with the desirability approach,an optimal mixing ratio of 0.078 wt%PACL,0.016 wt%H-G,and 27.882 wt%MDM was recommended,leading to a defoaming ratio of 98.34 vol%for residual foams and a moisture content of 56.72 wt%for pressure-filtration cakes.Our findings were demonstrated to be able to provide useful guidance for prediction and optimization of the in situ recycling indicators of EPB shield waste muck in metro tunnel construction sites.展开更多
The layout of the buckets for tunnel boring machine(TBM)directly affects the muck removal efficiency of cutterhead during excavation.In order to improve the muck removal performance for TBM,the optimal design of bucke...The layout of the buckets for tunnel boring machine(TBM)directly affects the muck removal efficiency of cutterhead during excavation.In order to improve the muck removal performance for TBM,the optimal design of bucket layout was investigated.The whole muck transfer process was simulated by discrete-element method(DEM),including the muck falling,colliding,pilling up,shoveling and transferring into the hopper.The muck model was established based on size distribution analysis of muck samples from the water-supply tunnel project in Jilin Province,China.Then,the influence of the bucket number and the interval angle between buckets on muck removal performance was investigated.The results indicated that,as the number of buckets increased from four to eight,the removed muck increased by 29%and the residual volume decreased by 40.5%,and the process became steadier.Different interval angles between buckets were corresponding to different removed muck irregularly,but the residual muck number increased generally with the angles.The optimal layout of buckets for the cutterhead in this tunnel project was obtained based on the simulation results,and the muck removal performance of the TBM was verified by the actual data in the engineering construction.展开更多
有人喜欢履带式挖掘机,因为它稳定;也有人喜欢轮式挖掘机,因为它灵活。当一台步履式挖掘机出现在自己面前时,所有人都不淡定了。步履式挖掘机如今对国内工程机械用户来说已不算什么新鲜事物,国内也有企业推出过步履式挖掘机产品,如徐工...有人喜欢履带式挖掘机,因为它稳定;也有人喜欢轮式挖掘机,因为它灵活。当一台步履式挖掘机出现在自己面前时,所有人都不淡定了。步履式挖掘机如今对国内工程机械用户来说已不算什么新鲜事物,国内也有企业推出过步履式挖掘机产品,如徐工在bauma China 2010上就推出了ET110型步履式挖掘机。尽管如此,Menzi Muck旗下的M系列步履式挖掘机在bauma China 2014上还是吸引了很多人的关注。兼得鱼和熊掌步履式挖掘机工作形式与传统履带式挖掘机和轮式挖掘机大致相同。展开更多
A huge amount of shield muck is generated during shield tunneling,and the reutilization of shield muck to produce tail grout has attracted growing attention,aiming to mitigate the environmental issues related to the t...A huge amount of shield muck is generated during shield tunneling,and the reutilization of shield muck to produce tail grout has attracted growing attention,aiming to mitigate the environmental issues related to the transport and disposal of shield muck.However,conventional binders,such as cement,used in this technique are associated with high carbon emission.Therefore,this study investigates the use of low-carbon binder,i.e.,carbide sludge(CS)-activated ground granulated blast furnace slag(GGBS),in shield muck treatment,aiming to achieve sustainable reutilization.Various commercial additives and phosphogypsum(PG),an industry waste,were added to further enhance the properties of treated shield muck.Results show that incorporating sulfate-containing additives to GGBS-CS-stabilized shield muck significantly reduced the setting time from 26.75 to 8.00–12.00 h,with Na_(2)SO_(4) and PG showing a relatively higher reducing rate.In addition,adding Na_(2)SO_(4) and PG to GGBS-CS-stabilized shield muck could enhance the 3-day strength by 67.0%and 37.0%,respectively,while their effects on improving the 28-day strength were marginal,yielding increases of just 16.0%and 0.4%.Results also indicated that additives led to a higher stone shrinkage rate of grout.Nonetheless,all additives posed negligible effects on the consistency and flowability.Microstructure analysis indicated that additives promoted the generation of ettringite(AFt)and aluminate ferrite monosulfate(AFm)phases.These phases consume free water and refine pores,leading to the higher stone shrinkage rate.Isothermal titration calorimetry highlighted that the additives affect the heat rate in the time interval of 4–50 h after mixing,and this should be the reason for the significant influence of additives on setting time and 3-day strength as well as limited impact on consistency and flowability.The findings confirmed the feasibility of using stabilized shield muck to produce tail grout,and PG is efficient in further enhancing its properties.展开更多
This paper proposed a framework for muck types identification based on data augmentation-assisted image recognition during shield tunnelling.The muck pictures were collected from the shield monitoring system above the...This paper proposed a framework for muck types identification based on data augmentation-assisted image recognition during shield tunnelling.The muck pictures were collected from the shield monitoring system above the conveyor belt.The data augmentation operations were then used to increase the quality of the original images.Furthermore,the Bayesian optimisation algorithm was employed to adjust the parameters of augmenters and highlight the features of the photos.The deep image recognition algorithms(AlexNet and GoogLeNet)were trained and enhanced by the augmentation images,which were used to establish the muck types identification models and assessed by the evaluation indices.Model efficiency was analysed through the performance and time cost of training and validation processes to select the optimal model for muck types identification.Results showed that the performance of identification models could be highly increased by data augmentation with Bayesian optimisation,and the enhanced GoogLeNet performed the highest efficiency for muck types identification.展开更多
Ecological concrete(EC)has received special attention recently,but its application has been largely limited by the high alkalinity caused by cement.In this study,a novel low alkalinity cementitious material(cementitio...Ecological concrete(EC)has received special attention recently,but its application has been largely limited by the high alkalinity caused by cement.In this study,a novel low alkalinity cementitious material(cementitious material developed from subway tunnel muck,S-CM)was developed from subway tunnel muck(STM).STM was activated by ball milling and the optimal time was 2 h.It was found that the solubilities of Si and Al of STM were enhanced by 1.74 and 2.36 times after mechanical activation.The leaching kinetics of Si and Al could be well described by Avrami model.The activated STM was a reactant in the cementitious system,and the higher Si and Al solubilities led to better gel generation.S-CM-2h exhibited a denser structure with lower porosity(34.88%),higher density(1.67 g/mL)and fewer macropores.The compressive strength of S-CM saw a notable increase from 4.06 to 10.14 MPa as a result of the denser microstructure and enhanced gel generation.Further study indicated that S-CM had much better environmental compatibility than sulphoaluminate cement in EC preparation.EC developed from S-CM had a 13.8%lower alkalinity,better root growth and a 47.5%higher dry weight of plants than EC developed from cement.This study provides a new approach for high value-added recycling of STM.展开更多
Estimating the properties of foam-conditioned clay soils is important for both conditioning and recycling goals in earth pressure balance(EPB)shield tunneling.In this study,the vacuum dewatering behaviors of foam-cond...Estimating the properties of foam-conditioned clay soils is important for both conditioning and recycling goals in earth pressure balance(EPB)shield tunneling.In this study,the vacuum dewatering behaviors of foam-conditioned clay soils were investigated,with their potential use as an alternative means to assess foam optimization being examined.A series of laboratory and fieldtests was conducted,including vacuum dewatering tests that considered the effects of filtrationtime and pressure,vane shear tests,and improved cone pullout tests under different gravimetric water content(w)and foam injection ratio(FIR)conditions.It was found that the filtrate loss(FL),which characterizes dewaterability,was increased by extended vacuum filtrationtime and elevated pressure.While increases in w and FIR enhanced FL,reductions were observed in the undrained shear strength(cu),tangential adhesion stress(Fs),and normal adhesion stress(Fn).Furthermore,a linear decrease in FL with increasing mechanical indices(cu,Fs,and Fn)was demonstrated by both laboratory and fielddata fittingresults,regardless of w,FIR,and dewatering conditions.This study provides novel insights into the understanding of vacuum dewatering mechanisms in foam-conditioned clay soils,while a simple approach is proposed for evaluating foam conditioning effectiveness in EPB shield tunneling applications.展开更多
基金supported by the National Youth Top-notch Talent Support Program of China(Grant No.00389335)the National Natural Science Foundation of China(Grant No.52378392)the“Foal Eagle Program”Youth Top-notch Talent Project of Fujian Province(Grant No.00387088).
文摘In situ recycling is one of the most effective methods to dispose of earth pressure balance(EPB)shield waste muck with residual foaming agents with high moisture content.In this context,response surface methodology(RSM)was employed to quantify the effects of independent variables,including flocculant dosage,defoamer dosage,and muck drying mass(MDM)and their interactions on defoaming-flocculation-dewatering indices.The polymeric aluminum chloride(PACL)and hydroxy silicone oil-glycerol polypropylene ether(H-G)were selected as the flocculant and defoamer.The contents of surfactants and foam stabilizers in residual foaming agents were determined using the proposed empirical equation.The defoaming ratio,antifoaming ratio,turbidity,moisture content,filtration loss ratio,and fall cone penetration depth were considered as dependent variables.The accuracy of developed RSM models was verified by the analysis results of variance,residuals,and paired t-test.Combined with the desirability approach,an optimal mixing ratio of 0.078 wt%PACL,0.016 wt%H-G,and 27.882 wt%MDM was recommended,leading to a defoaming ratio of 98.34 vol%for residual foams and a moisture content of 56.72 wt%for pressure-filtration cakes.Our findings were demonstrated to be able to provide useful guidance for prediction and optimization of the in situ recycling indicators of EPB shield waste muck in metro tunnel construction sites.
基金Project(51475478)supported by the National Natural Science Foundation of ChinaProject(2012AA041801)supported by the National High Technology Research and Development Program of China+1 种基金Project(2014FJ1002)supported by the Science and Technology Major Project of Hunan Province,ChinaProject(2013CB035401)supported by the National Basic Research Program of China。
文摘The layout of the buckets for tunnel boring machine(TBM)directly affects the muck removal efficiency of cutterhead during excavation.In order to improve the muck removal performance for TBM,the optimal design of bucket layout was investigated.The whole muck transfer process was simulated by discrete-element method(DEM),including the muck falling,colliding,pilling up,shoveling and transferring into the hopper.The muck model was established based on size distribution analysis of muck samples from the water-supply tunnel project in Jilin Province,China.Then,the influence of the bucket number and the interval angle between buckets on muck removal performance was investigated.The results indicated that,as the number of buckets increased from four to eight,the removed muck increased by 29%and the residual volume decreased by 40.5%,and the process became steadier.Different interval angles between buckets were corresponding to different removed muck irregularly,but the residual muck number increased generally with the angles.The optimal layout of buckets for the cutterhead in this tunnel project was obtained based on the simulation results,and the muck removal performance of the TBM was verified by the actual data in the engineering construction.
文摘有人喜欢履带式挖掘机,因为它稳定;也有人喜欢轮式挖掘机,因为它灵活。当一台步履式挖掘机出现在自己面前时,所有人都不淡定了。步履式挖掘机如今对国内工程机械用户来说已不算什么新鲜事物,国内也有企业推出过步履式挖掘机产品,如徐工在bauma China 2010上就推出了ET110型步履式挖掘机。尽管如此,Menzi Muck旗下的M系列步履式挖掘机在bauma China 2014上还是吸引了很多人的关注。兼得鱼和熊掌步履式挖掘机工作形式与传统履带式挖掘机和轮式挖掘机大致相同。
基金supported by the National Natural Science Foundation of China(No.52308366)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.23KJB560023).
文摘A huge amount of shield muck is generated during shield tunneling,and the reutilization of shield muck to produce tail grout has attracted growing attention,aiming to mitigate the environmental issues related to the transport and disposal of shield muck.However,conventional binders,such as cement,used in this technique are associated with high carbon emission.Therefore,this study investigates the use of low-carbon binder,i.e.,carbide sludge(CS)-activated ground granulated blast furnace slag(GGBS),in shield muck treatment,aiming to achieve sustainable reutilization.Various commercial additives and phosphogypsum(PG),an industry waste,were added to further enhance the properties of treated shield muck.Results show that incorporating sulfate-containing additives to GGBS-CS-stabilized shield muck significantly reduced the setting time from 26.75 to 8.00–12.00 h,with Na_(2)SO_(4) and PG showing a relatively higher reducing rate.In addition,adding Na_(2)SO_(4) and PG to GGBS-CS-stabilized shield muck could enhance the 3-day strength by 67.0%and 37.0%,respectively,while their effects on improving the 28-day strength were marginal,yielding increases of just 16.0%and 0.4%.Results also indicated that additives led to a higher stone shrinkage rate of grout.Nonetheless,all additives posed negligible effects on the consistency and flowability.Microstructure analysis indicated that additives promoted the generation of ettringite(AFt)and aluminate ferrite monosulfate(AFm)phases.These phases consume free water and refine pores,leading to the higher stone shrinkage rate.Isothermal titration calorimetry highlighted that the additives affect the heat rate in the time interval of 4–50 h after mixing,and this should be the reason for the significant influence of additives on setting time and 3-day strength as well as limited impact on consistency and flowability.The findings confirmed the feasibility of using stabilized shield muck to produce tail grout,and PG is efficient in further enhancing its properties.
基金funded by the Guangdong Provincial Basic and Applied Basic Research Fund Committee(2022A1515240073)“The Pearl River Talent Recruitment Program”in 2019(Grant No.2019CX01G338),Guangdong Province,China.
文摘This paper proposed a framework for muck types identification based on data augmentation-assisted image recognition during shield tunnelling.The muck pictures were collected from the shield monitoring system above the conveyor belt.The data augmentation operations were then used to increase the quality of the original images.Furthermore,the Bayesian optimisation algorithm was employed to adjust the parameters of augmenters and highlight the features of the photos.The deep image recognition algorithms(AlexNet and GoogLeNet)were trained and enhanced by the augmentation images,which were used to establish the muck types identification models and assessed by the evaluation indices.Model efficiency was analysed through the performance and time cost of training and validation processes to select the optimal model for muck types identification.Results showed that the performance of identification models could be highly increased by data augmentation with Bayesian optimisation,and the enhanced GoogLeNet performed the highest efficiency for muck types identification.
基金supported by the National Natural Science Foundation of China(Nos.52170144 and 52470167)the Eco-Environmental Double Carbon Project of RCEES CAS,China(No.RCEES-TDZ-2021-31)。
文摘Ecological concrete(EC)has received special attention recently,but its application has been largely limited by the high alkalinity caused by cement.In this study,a novel low alkalinity cementitious material(cementitious material developed from subway tunnel muck,S-CM)was developed from subway tunnel muck(STM).STM was activated by ball milling and the optimal time was 2 h.It was found that the solubilities of Si and Al of STM were enhanced by 1.74 and 2.36 times after mechanical activation.The leaching kinetics of Si and Al could be well described by Avrami model.The activated STM was a reactant in the cementitious system,and the higher Si and Al solubilities led to better gel generation.S-CM-2h exhibited a denser structure with lower porosity(34.88%),higher density(1.67 g/mL)and fewer macropores.The compressive strength of S-CM saw a notable increase from 4.06 to 10.14 MPa as a result of the denser microstructure and enhanced gel generation.Further study indicated that S-CM had much better environmental compatibility than sulphoaluminate cement in EC preparation.EC developed from S-CM had a 13.8%lower alkalinity,better root growth and a 47.5%higher dry weight of plants than EC developed from cement.This study provides a new approach for high value-added recycling of STM.
基金supported by the National Youth Top-notch Talent Support Program of China(Grant No.00389335)the National Natural Science Foundation of China(Grant No.52378392)the“Foal Eagle Program”Youth Top-notch Talent Project of Fujian Province(Grant No.00387088).
文摘Estimating the properties of foam-conditioned clay soils is important for both conditioning and recycling goals in earth pressure balance(EPB)shield tunneling.In this study,the vacuum dewatering behaviors of foam-conditioned clay soils were investigated,with their potential use as an alternative means to assess foam optimization being examined.A series of laboratory and fieldtests was conducted,including vacuum dewatering tests that considered the effects of filtrationtime and pressure,vane shear tests,and improved cone pullout tests under different gravimetric water content(w)and foam injection ratio(FIR)conditions.It was found that the filtrate loss(FL),which characterizes dewaterability,was increased by extended vacuum filtrationtime and elevated pressure.While increases in w and FIR enhanced FL,reductions were observed in the undrained shear strength(cu),tangential adhesion stress(Fs),and normal adhesion stress(Fn).Furthermore,a linear decrease in FL with increasing mechanical indices(cu,Fs,and Fn)was demonstrated by both laboratory and fielddata fittingresults,regardless of w,FIR,and dewatering conditions.This study provides novel insights into the understanding of vacuum dewatering mechanisms in foam-conditioned clay soils,while a simple approach is proposed for evaluating foam conditioning effectiveness in EPB shield tunneling applications.
