近间距大直径公路盾构隧道施工相互影响分析

结合一外径11.36m、近距段净距4.0～5.7m的上海某公路盾构隧道土体和管片位移及应变的监测成果,就后建隧道施工对先建隧道的影响进行了分析。分析结果表明,盾构的推进使隧道间土体朝掘进方向和已建隧道方向侧移,沿深度的最大侧移量发生在隧道中心深度以上0.2D(D为隧道外径)左右;盾尾到达及管片脱出注浆工况阶段,隧道间土体及已建隧道临近面上拱腰处的侧移量达到最大;已建隧道管片呈现上部内敛、下部外扩的变形形态,且临近后建隧道面变形值较大。

Analysis of construction interaction of highway shield tunnels with short-distance and large diameter

Based on the monitoring data from two short-distance parallel highway tunnels with 11.36 m of external diameter and 4.0 to 5.7 m of spacing, effect of latter-constructing tunnel on former-constructed tunnel was analyzed. The results show that the soil between two tunnels moves simultaneously along parallel and perpendicular tunneling direction. The maximum lateral displacements along depths locate around 0.2 time external diameter above the depth of tunnel circle center. The lateral displacements of the soils between two tunnels and waist segment of former-constructed tunnel reach the maximum values at the stages of shield tail passing and subsequent segment installation. Convergence measurements indicate the segments of former-constructed tunnel move inward at the upper part while move outward at the lower part.