摘要
Abstract
On the premises of ideal simultaneous backfill grouting, and without regard to the influences of the change of grout characteristics, the upward movements of segments in three-dimensional annular space at the rear of shield tail were researched. The upward buoyancy acted on segments was divided into two parts, namely, the generalized dynamic buoyancy changing with ground conditions and buried depth of tunnel, and the static buoyancy depending on surrounding liquid grout. The formulas of the two types of upward buoyancy were derived. The dynamic buoyancy existed for a long time within certain distance range at the rear of shield tail. The action range of static buoyancy was given based on the change law of the grout pressure gradient in the cross section of tail void. On the basis of the whole floating mode of the segments at the rear of shield tail, and considering the longitudinal constraints between segments, the expression for the least yield strength of grout was obtained to maintain the anti-floating stability of tunnel. The decisive role of the yield strength of grout on maintaining the anti-floating stability of tunnel was made clear, and the positive role of surrounding pressure on improving the yield strength of grout was also made clear.关键词
盾构隧道/同步注浆/盾尾空隙/上浮力/屈服强度Key words
Shield tunnel/ Simultaneous backfill grouting/ Annular space at the rear of shield tail/ Upward buoyancy/ Yield strength分类
交通工程
