| With the continuous development of transportation engineering and urban underground space,the construction of the retaining wall needs to meet higher technical and functional requirements,such as space occupation,density,bearing capacity,and waterproof quality.The acceleration of urbanization and industrialization leads to an increasing amount of industrial waste,and the recycling rate of waste is less than 60%.Therefore,the research trends that green construction demands recycling materials from industrial facilities and exploring the potential uses of waste during a second life cycle has become a major topic in today’s economic and social development.To improve the recovery rate of fly ash,slag,and other solid wastes,these industrial waste has been applied as filling materials of pavement engineering,curing materials of cement-soil diaphragm wall,and soil hardening agents in many practical projects.Based on the above background,the GS soil hardening agent instead of cement is being applied to the construction of the underground diaphragm wall in this paper.Firstly,the laboratory tests are carried out to analyze the unconfined compressive strength,compression strength,and shear strength of the soil samples.Then,the strength,compression performance,and shear properties of GS-stabilized soil and cemented soil are analyzed comparatively.Lastly,the chemical and physical reaction mechanism of GS soil hardening agent mixed with soil is to be analyzed.The crystal formation,pore distribution,and other structural characteristics of GS-stabilized soil can be observed by the electron microscope analysis and X-ray analysis,which provides experimental data and theoretical guidance for the extensive application of GS soil hardening agent in engineering.(1)Comparative study on strength characteristics of GS-stabilized soil and cemented soilThe experimental study of the strength of both GS-stabilized soil and cemented soil are carried out according to different test categories and requirements.The main factors that affecting the compressive strength,shear strength,and compression modulus are investigated from the perspective of the types of curing agent,dosage,reinforcement soil,and curing time.Then,the linear relationship between the unconfined compressive strength and modulus of deformation of both stabilized soil is proposed.The test results show that the unconfined compressive strength,compressive modulus,and shear strength increase elapsed against curing time.In detail,the stiffness and brittleness of the GS-stabilized soil are better than the cemented soil,relatively.(2)Study on microscopic mechanism of GS-stabilized soil and cemented soilThe scanning electron microscopy(SEM)and X-ray diffraction(XRD)tests are carried out on the soil samples to observe the microstructure and chemical composition of both stabilized soil.The generation rule of the crystal structure of the GS-stabilized soil and the cemented soil can be investigated to analyze the basic principle of the solidifying mechanism.The results of the microscopic test show that the grains of GS-stabilized soil are closely arranged.And the microstructure characteristics occupy similar regularity with the macroscopic mechanical characteristics.The GS soil hardening agent is better than cement in microstructure improvement,uniform dispersion,and strength increasing.(3)Application of GS soil hardening soil in engineeringThe application effect of GS soil hardening agent in actual engineering is studied in the field tests to analyze the mechanical properties and engineering applicability of GS-stabilized soil.The field tests show that the integrity of the GS-stabilized soil pile is better than that of the cemented soil pile.The compressive strength of the GS-stabilized soil pile varies with the soil properties and increases with the elapsed time.Based on the characteristics of fast strength in early-stage and high strength in late-stage,GS soil hardening agent can be applied to pavement engineering which also meets the demand of economic benefit. |
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