| In the embankment project of coastal soft soil foundation,the filling engineering of the closed earth is large,the time of consolidation is long and the construction is difficult,which seriously affects the construction speed and quality of the embankment and dam.The near dike sea muddy mud is the raw material soil,which avoids the mining and mining of sand and gravel on land.It has certain environmental and economic benefits,but the water content of the muddy mud is high,the natural consolidation is long,sometimes it even needs three years and five years,which seriously restricts the construction of the sea embankment project.In order to solve the problem of complicated construction and long period of construction,this paper takes the accelerated consolidation of the closed gas earth as the research object.Through the laboratory test and the practical engineering construction technology,the laboratory test results are combined with the concrete technology to solve the problem of the rapid formation of the closed earth.The main work of this article is as follows:(1)investigation and research summarize the construction method and quick filling method of the closed gas earthwork at this stage.(2)the main physical and chemical characteristics of the sea muddy mud near a reclamation sea embankment in Xiangshan,Ningbo,were analyzed by conventional soil test and chemical experiments,including the main components,water content,density,pore ratio,particle size gradation,optimal water content,liquid plastic limit,plastic index and liquid index,etc.(3)through the laboratory unconfined compressive strength test,the strength,deformation and permeability of the solidified sea coating mud were analyzed under the effects of different dosage of cement,different amount of fly ash and phosphogypsum,and the effect of water content,content and curing age on the mud quality of sea coating was studied.(4)through the SEM test,the microscopic characteristics of solidified sea mud,including cement,garbage fly ash and phosphogypsum,were studied,and the curing mechanism was explored.(5)combining with a certain reclamation project in Xiangshan,Ningbo,the paper studies the two construction techniques of consolidation and consolidation of the closed earth Earthwork by mixing consolidation and pipeline transportation,and analyzing the practical significance and guiding role of the laboratory research theory.The main results are as follows:(1)the average value of the water cut obtained by the compaction test is 20.86%.Near the base water content,with the increase of water content,the strength of the soil is increased with the increase of water content.With the increase of curing age,the hydration products in the cement soil increase gradually and the strength gradually increases.(2)in the vicinity of the base water content,it is found that the cement mixing ratio of the best reinforced sample soil is 8%-12% and the water content is higher than the base water content.When the water content is 15.86%,20.86%,25.86%,the strength of the reinforced specimen increases first and then decreases with the increase of cement content.Because the amount of water is fixed,and the amount of water that can be supplied to the cement to produce ripening reaction is quantitative and the amount of cement is increased,the phenomenon of strength reduction will appear.(3)the construction method of consolidation agent and the construction method of mixing consolidation agent in pipeline transportation in the construction of closed earth are a good way to accelerate the consolidation of the closed shore embankment.The former is suitable for soft foundation treatment with depth less than 8m and water content greater than 50%,soft foundation engineering with bearing capacity less than 20 t after treatment,and the latter has no soft foundation treatment depth and the limit of bearing capacity after treatment.(4)the use of advanced technology and equipment in practical engineering can achieve or close to the effect of indoor test as long as the solidifying agent and silt are fully stirred and evenly stirred.(5)this paper solves the problem that the closed soil in the soft soil foundation of the coastal area is difficult to consolidate in three years and five years under natural conditions.Combined with concrete engineering examples,this paper studies the construction technology of closed air earthwork,which has fast curing speed,simple construction operation and high construction efficiency.The consolidation strength of sea coating mud can reach more than 300 kPa,which meets the requirements of subsequent construction and speeds up the construction progress of closed earth earthwork.The research and application of the accelerated consolidation of the closed earth has changed the dependence of the seawall project on the land earthwork resources,which is of great practical significance. |
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