| Because of its obvious advantages,shield tunneling has become the first choice for rail transit construction.In the process of shield tunneling,it is inevitable to produce a large amount of shield dredge.Jinan alone,the long-term residue production will reach more than one trillion cubic meters.The transportation and stacking of large amount of shield dregs have caused serious environmental pollution.The state put forward the strategy of "carbon neutrality" and"carbon peak",and vigorously promoted the research on solid waste recycling technology.As a kind of solid waste,resource utilization of shield dredge has significant economic and social benefits.In this paper,the shield dredge of Jinan metro is taken as an example,and the reuse method of preparing high-performance cementing material and grouting material aggregate is proposed based on the project "Green and safe Construction Method and Collaborative Control Platform of Quanyu Shield Subway" of the Ministry of Housing and Urban-Rural Development.By means of experiment,theoretical derivation and simulation,lightweight grouting material and synchronous grouting diffusion mechanism of shield dredge foundation are studied,and the following research results are obtained:(1)In view of the geological characteristics of Jinan Spring area,through the analysis of the stratum passing through Line 4 and Line 6.it is concluded that the subway residue in Jinan area is mainly composed of clay,limestone and diorite,of which clay content is the most,diorite second,limestone content is less.The distribution of shield residue in Jinan Metro Line 2 is analyzed,and the physical and chemical analysis of shield residue in Jinan Metro Line 2 is carried out,and the physical moisture content,apparent density,specific gravity,porosity ratio,permeability coefficient and particle size distribution of typical residue in representative sections are analyzed.XRF,XRD and thermogravimetric analysis were used to analyze its composition and thermal decomposition characteristics,and the feasibility of preparing silicaaluminum series cementation materials and lightweight grouting materials was demonstrated.(2)The complexity problem of shield residue composition is solved by using shield residue as the main raw material,adopting the design method of utilization rate value and taking mineral composition as the orientation.By experiment means,reveals the different promoter,calcination temperature and rate of value under the condition of high bailey,gelled material forming mechanism,through the performance optimization experiment,analyzes the bailey and high condensation,cement materials properties and strength characteristics,formed the shield waste residue as raw material preparation,o base high bailey and high residue in gelled material technology.By means of composite mixing,the advantages of high belite cementitious material and high Alite cementitious material are complementary to each other,and the preparation technology of shield slag cementitious material is formed.(3)The factors influencing the properties of lightweight grouting materials based on residue are analyzed.By means of macroscopic mechanical experiment and SEM microscopic analysis,the strength and evolution properties of different water-cement ratios,fly ash content,different admixtures and different densities were revealed.Aiming at the unstable clay content of shield dredge,the lightweight grouting material with high flow and full clay dredge was developed.Finally,the optimal ratio of slurry fluidity and strength was obtained,forming the preparation technology of lightweight grouting material with shield dredge.(4)The types of shield tail clearance and synchronous grouting are analyzed.The pressure-density model of lightweight grouting material is revealed by means of theoretical derivation and experiment.The diffusion models of circular grouting and longitudinal grouting are derived,and the superiority of light grouting material in filling synchronous grouting is demonstrated.Based on the spherical hole expansion theory,the spherical and cylindrical synchronous grouting compaction models of lightweight grouting materials were derived,and the pressure distribution model and segment compression model were obtained.Based on the cylindrical hole expansion model,a vertical displacement calculation method based on soil porosity was proposed.A slurry-soil consolidation thickness model was established to reveal the synchronous dissipation process of grouting pressure for lightweight grouting materials.(5)analysis of the influence of synchronous grouting pressure control strata,slurry and construction influence factors,puts forward the spread of different types of synchronous grouting critical pressure and the optimal discriminant method,summarizes the different mode of synchronous grouting grouting pressure and the calculation model of shield segment lining using case analysis,the optimal calculation method,this paper expounds the synchronous grouting pressure.The pressure distribution and dissipation process of ordinary grout and light grout in grouting diffusion are compared,and the superiority of material in grouting is proved.Based on Jinan Metro Line 4,the field use of light grouting material for shield dredge foundation was carried out,and the data of density detection,surface settlement monitoring and segment floating monitoring proved that the light synchronous grouting material could effectively fill and reinforce the stratum. |
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