Based on different classes of surrounding rocks

the numerical simulation of construction process is studied for three roadway tunnels with small spacing

adopting the typical method of double side excavation. The damage characteristic and the deformation law of surrounding rocks are given in the construction process for the different classes of surrounding rocks of three driveway tunnels. The comparability of the distributive law of deformation along the tunnel boundary is indicated for different classes of surrounding rocks; and the relative ratio of maximum displacement is obtained. By comparing the deformation and the plastic damage law in the interval wall between tunnels

the minimum spacing is selected for engineering design reference in three roadway tunnels. It is shown from analysis that the reasonable spacing is more than 0.45B for surrounding rock class II and between 0.35B and 0.45B for surrounding rock class III and between 0.20B and 0.35B for surrounding rock classification IV and V. The key locations of measurement and control are given for the feedback information construction

and these provide the reference data and the theoretical basis for the development and construction design of highway tunnels with small spacing.