Models for predicting surface settlements due to soft ground tunneling

摘要

An empirical model, to predict maximum surface settlements due to soft ground tunneling combined with a modified Gaussian distribution settlement model, to define the shape of the settlement trough, are presented in this paper. The empirical model is based on review of worldwide case history data on soft ground tunneling. Equations were developed to predict maximum surface settlements due to single tunnels excavated in sand and in clay. These equations were then extended to the case of twin tunnels using a numerical model calibrated from the single tunnel analysis case. Maximum surface settlements predicted by the proposed empirical equations were then combined with a modified Gaussian distribution model to estimate settlements at any location along a tunnel alignment. Better agreement between the predicted and actual settlements was achieved over the traditional Gaussian distribution model, as demonstrated in two selected case histories.