ANALYSIS OF DOUBLE-LAYERED LINER BEHAVIORS OF SHIELD TUNNEL UNDER ACTIVE MOVING GROUND-FISSURES

The shield tunnel under the environment of moving ground-fissures will bear additional stress and deformation which are larger than those of normal condition when subjected to the relative moving of ground-fissures. so,the tunnel-lining will lose the function both in the aspects of strength and watertight. In this paper,a kind of double-layered lining which casts an integral reinforced concrete internal lining inside duct pieces,is developed to co-bear the additional loads and reduce the stress and deformation of structures. Numerical analysis is performed to analyze the double-layered lining behavior of stress and deformation subjected to the actions of ground-fissures. The relative moving distance,the strength and thickness of inner lining are the main influencing factors,and some conclusions with guiding significance to practical engineering are drawn. The results show that the integral reinforced concrete internal lining inside duct pieces can effectivelyreduce the stress and deformation of the tunnel-lining;the stress and deformation of the lining has linear proportion with the relative distance of ground-fissures;the thickness of the internal liner has great impact on the stress and deformation of the lining,and the stress and deformation of the lining become smaller when there is bigger thickness of the internal lining,but when the thickness of the internal lining exceeds 300 mm,there only exists weaker influence with the increase of the thickness;The strength of inner lining has smaller impact on the stress and deformation of the liner,and in the specific engineering C30 concrete is enough.