Study On The Solidification Improvement Of Silty Soil And Its Action Mechanism

Due to the diversification of topography and landforms in China,there are many river beaches and beaches.Under the long-term geological action,a large amount of silt or silt soil is formed.Among them,the silt soil is mainly brownish yellow and taupe,which has the characteristics of high water content,high compressibility,high rheology and low natural strength.The curing improvement is to add a solidified material to the muddy soil with poor mechanical properties,and improve the compressive strength,freeze resistance,dryness resistance and permeability of the soil by chemical and physical action of the solidified material to achieve improved muddy quality.The purpose of the nature of the soil.The treatment of silt soil by curing improvement can not only effectively improve its compressive strength and other properties,but also help to protect land resources and the environment.In order to improve the characteristics of poor muddy soil performance,a small amount of water glass,calcium carbonate,raw gypsum,FDN water reducing agent and triethanolamine mixed external admixture are mixed in the cement-based curing agent(for convenience,short for short)"YG").The test shows that a small amount of YG is added to the single cement solidified modified muddy soil,and the improvement effect is obviously enhanced.In this paper,the composite solidification agent of cement and YG external admixture is used to cure and improve the silt soil.The first research content is to determine the optimal ratio of each chemical external doping agent in YG external admixture by experiment;the second is to test the basic mechanical properties of cement solidified soil and cement-YG solidified soil under different dosages and different ages;Thirdly,according to SEM scanning electron microscopy and XRD diffraction test,the microstructure observation and analysis of the cement-YG solidified soil and the quantitative analysis of the material composition were carried out to study the mechanism of the cement-YG solidified modified muddy soil.The research results of this paper are as follows:(1)For the silty soil,the preparation of the external admixture YG is completed on the basis of the cement-based curing agent.It is also verified that the cement-YG solidified modified muddy soil is superior to the cement solidified and improved silt soil in early strength and late strength.(2)The performance of the cement-solidified soil and the cement-YG solidified soil were compared and analyzed by the performance test of solidified modified muddy soil.It is verified that the compressive strength,permeability,dry-wet resistance and freeze-thaw resistance of cement-YG solidified soil are better than cement solidified soil.(3)Analyze the microstructure and composition of cement-YG solidified silt soil and study its mechanism of action,and clarify the excitation effect of YG external admixture in cement-YG solidified modified muddy soil.The structure and composition of the cement-YG solidified modified muddy soil were significantly changed by SEM scanning electron microscopy and XRD diffraction analysis.(4)The analysis of the action mechanism of cement-YG curing agent is mainly due to the filling of large pores in the soil after solidification and improvement,the porosity is reduced,and the overhead structure is obviously optimized.The content of calcium hydroxide crystals,hydrated calcium silicate and ettringite is increased,the cementation between the clays is strengthened,and the strength of the solidified and improved sludge soil is effectively improved.