Model test study on stability of excavation face of slurry shield in silty clay stratum
Based on the project background of shield tunnel at Hualong Station and Lianhua Stations on the right line of Pazhou Branch Line of Guangzhou Pearl River Delta Intercity Railway,this paper studies the stability problem of excavation face of shield tunnel construction in sandy soft soil with large water content by establishing a laboratory similar test model.When the shield construction in sandy soil causes the instability of the excavation face,the soil arching effect will appear in the stratum,and the ground surface will have a hysteresis effect on the active damage of the excavation face.However,for the sandy soil with high water content,high water head will produce certain excess pore water pressure and seepage,thus weakening the soil strength and weakening the soil arching effect.Therefore,for the sandy soil with high water content,although the existence of water makes the sandy soil have a certain self-stability,it only makes the deformation lag and cannot be used as a basis for reducing the support pressure.The shallower the shield soil depth,the larger the floating range of grouting pressure and the greater the disturbance to the surface.The safe range of mud pressure and rotary speed of cutter disc are determined by model test,which can provide reference for practical engineering construction.
soft formationexcavation face stabilizationultimate mud pressureland surface subsidencerange of influence
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维普
