Correction of Peck Settlement Formula for Large Diameter Shield Construction in Upper Soft and Lower Hard Strata

In order to reasonably predict the surface settlement caused by the construction of large-diameter slurry shield, this paper conducts regression analysis on the actual measured data in the field and studies the adaptability of Peck's formula in the prediction of settlement of large-diameter slurry shield, while introducing the correction factor α for the maximum surface settlement and the correction factor β for the width of the settlement trough to correct Peck's formula. The results show that: There is a significant difference between the measured settlement value of large diameter slurry shield tunneling in upper soft and lower hard composite strata and the predicted settlement value of Peck formula after linear regression. When the value of α is distributed between 0.1 and 0.5 and the value of β is distributed between 0.5 and 1.0, it can better reflect the surface settlement deformation of large diameter slurry shield in the upper soft and lower hard strata. By comparing and analyzing the correction coefficients of settlement trough for small diameter and large diameter shield tunnels, it can be seen that the variation range of the correction coefficient of settlement trough increases with the increase of the excavation cross-sectional area and the difference in soil properties of the excavation surface. The research results can expand the application scope of the Peck formula and provide a reference for the design and construction of large diameter shield tunnels.