温州盾构隧道穿越软土物理力学性质试验研究OA

In the subway engineering of soft soil areas,the physical indicators and static-dynamic properties of soft clay are important factors influencing subway design,construction,and project cost.In particular,during subway operation,cyclic dynamic stress induced by running trains acts on the underlying soft soil foundation of the tunnels,thus greatly affecting the operational safety and maintenance of the subway.Based on the Wenzhou Metro M1 Line project,laboratory geotechnical tests and systematic research were carried out on the soft soil through shield tunnels to obtain the basic physical indicators of Wenzhou soft clay,with its consolidation,shear characteristics,and cyclic dynamic characteristics under traffic loads analyzed.The test results indicate that the soil surrounding the shield tunnel is typical soft soil,exhibiting unfavorable engineering properties such as high water content,high void ratio,high compressibility,high sensitivity,and low strength.The preconsolidation pressure presents regular variation,while shear strength indicators show great discreteness.The consolidated undrained triaxial shear tests reveal that most soil samples exhibit strain-softening behavior,with failure line slopes ranging from 1.39 to 1.52 and critical state line(CSL)slopes between 1.47 and 1.51.Comparison between the cyclic dynamic properties of undisturbed and remolded soil shows that the strain of remolded soil is generally greater than that of undisturbed soil.A cumulative strain prediction model was built under cyclic traffic loads for both undisturbed and remolded soil.