Study on EPB Shield Excavation Parameters in Water-Rich Sandy Cobble Stratum in Chengdu

Excavated volume is one of the active control parameters of the earth pressure balance shield. In order to examine the influence of excavated volume on shield tunnel construction, and mitigate potential adverse effects from abnormal data, statistical analysis and theoretical derivation of earth pressure balance shield are carried out by analyzing the field excavation data. Research shows that the buried depth of the shield tunnel has no direct influence on the excavation parameters of shield tunneling. The range of the volume coefficient and density coefficient of the excavated soil is obtained. Also, it is concluded that the normal distribution and T estimation method is suitable in the parameter study of the excavated volume in water-rich sandy cobble stratum. At present, the research results of excavated quantity parameters are only applicable to water-rich sandy cobble stratum and composite stratum dominated by sand cobble. Before excavation, the research conclusions can be used to determine the range of excavated volume. During excavation, the proposed research can predict the excavation volume of the excavation ring, and can also predict the excavation soil density of the face. The shield tunneling mode and tunneling parameters can therefore be adjusted in time.