Abstract:

Based on the different analysis principles, the methods used to predict the ground surface settlement caused by the construction of twintube tunnels are classified into semiempirical analysis method, theoretical analysis method and numerical analysis method, whose advantages and disadvantages are analyzed. Curves of measured ground surface settlement caused by the construction of 41 twintube tunnels at home and abroad are collected. Through the analysis on the shape and causes of the curves as well as the analysis on the data of the maximum ground surface settlement, the following three main characteristics are summarized for the distribution curves of the ground surface settlement caused by the shield construction of twintube tunnels: 1) The ground surface settlement curves mainly present “unimodal” and “bimodal” forms. Both the distance between twin tubes and the tunnel depth have great influence on the curve forms; 2) The main factors that have influence on the ground surface settlement distribution curves include the geological factors, the environmental factors and the construction factors; 3) The maximum ground surface settlement is closely related to the tunnel depth, the distance between the twin tubes, the ground conditions and the shield tunneling method.

Key words: shield tunnelling, twintube tunnel, ground surface settlement, field measurement