Study on Construction Parameters of Shield Crossing River Course in Water-Rich Sandy Cobble Stratum
Water-rich sandy cobble stratum has the characteristics of high content of large-size cobble,high permeability,high water content and poor formation stability.Combined with the project of Luoyang Metro Line 2 Museum Station-Jiudu West Road Station,the construction difficulties of water-rich sandy cobble stratum crossing the river are analyzed,and the control requirements are put forward.Using numerical analysis method,the influence of grouting pressure and soil bin pressure on surface deformation during shield tunneling is analyzed.According to the analysis results,the grouting pressure mainly affects the settlement behind the shield tail.With the increase of grouting pressure,the settlement behind the shield tail decreases gradually,and the influence on the deformation of the cutter head is small.The earth pressure has a great influence on the deformation of the stratum in front of the cutterhead.With the increase of the earth pressure,the stratum in front of the cutterhead gradually changes from settlement to uplift,and the earth pressure also has a certain influence on the settlement of the shield tail.According to the analysis results and control requirements,the reasonable values of grouting pressure and soil bin pressure are proposed,and on this basis,the total thrust of jacks and tunneling speed are proposed,which have achieved good results in engineering practice.
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