Experimental Study On Physical-Mechanical Behavior Of Mud-soil Mixture At Slurry Shield Excavation Face

In recent years,slurry shield has been widely applied in the construction of underground engineering in our country.Maintaining the stability of the excavation surface is the key to the successful implementation of the slurry shield,and the properties of the excavated surface mud-soil mixture are the direct factor affecting the stability of the excavation surface.Therefore,it is of great theoretical value and wide application prospect to study the physical-mechanical properties of the mud-Soil mixture.In this paper,the feasibility of artificial preparation of filter cake and filter cake-fine sand mixture was confirmed by model test,the physical and mechanical properties of the mud-soil mixture in the excavated surface are studied by physical mechanics test.The physical and mechanical properties of excavation surface Mud-Soil mixture were studied with the change of bentonite content,CMC content,sand partical size,and so on.The main research work and innovation are as follows:(1)The mud model test was carried out,from the form,water content,permeability and so on,the filter cake and filter cake-fine sand mixed soil of model test and artificial preparation of filter cake and filter cake-fine sand mixed soil were compared.The results showed that the artificial filter cake and filter cake-fine sand mixed soil were within the scope of the model test,and it was clear that the artificial mud and mixed soil was in accordance with the model test.(2)The physical test of filter cake and filter cake-fine sand mixed soil were carried out.The changes of filter cake and filter cake-fine sand mixed soil with bentonite content,CMC content and sand particle size were discussed and analyzed.It was clear that the liquid limit was an important factor affecting the quality of filter cake and filter cake-fine sand mixed soil.(3)A series of one-dimensional compression tests were carried out on the artificial filter cake and filter cake-fine sand mixed soil by low stress initiation and improvement of light consolidation.The effects of different bentonite,CMC content and different initial water content on the compression properties of filter cake were studied.The effects of different bentonite,CMC content and sand partical-size size on the compression properties of filter cake-fine sand mixed soil were studied.(4)Based on the one-dimensional consolidation theory,the permeability coefficient was obtained through the consolidation test data.The variation law of filter cake permeation coefficient and bentonite and CMC content was clarified.It was clear that the permeability coefficient of mixed soil varied with bentonite,CMC content and sand particle size.The main factors influencing the permeability coefficient of filter cake and mixed soil were the liquid limit and pore ratio.The relationship between the shear strength and the water content and the liquid limit of the filter cake and mixed soils was analyzed...