Ground settlement induced by double-O-tube shield tunneling under different construction conditions

The formulae for calculating the soil settlement induced by double-O-tube shield tunneling under the normal and rotated construction conditions are derived by use of the stochastic medium theory. The case studies show that the predicted surface settlements are in good agreement with the observed ones. The soil subsidence curve induced by double-O-tube shield tunneling under rotated construction condition is asymmetric, the maximum value appears at the downward rotation side, and it can be explained well why the observed soil settlement curve is asymmetric. At the same rate of soil loss, the maximum settlement value induced under the rotated condition is smaller than that under the normal condition, but the settlement trough width is larger. The variation rules of soil settlement at different depths induced under normal and rotated conditions are also different.