摘要
盾构衬砌管片在拼装和使用中出现很多裂缝问题,通过衬砌管片的加载考察分析影响衬砌管片裂缝开展的因素,为管片结构优化设计提供技术支持。分别采用普通盾构衬砌管片(纵筋采用直径18mm的HRB335钢)和加重盾构衬砌管片(纵筋采用直径22mm的HRB335钢)两种管片的加载裂缝对比情况来分析影响衬砌管片裂缝的因素。试验结果表明,初始裂缝主要受混凝土的影响,钢筋作用不明显。加载力越大,裂缝开展深度越大。破坏时加重管片的混凝土破坏更为严重。裂缝开展严重地方在中心螺栓孔附近,此段主要承受弯矩,两旁螺栓至接头处基本不开裂,此段主要受轴向力的作用。外侧保护层破坏时钢筋屈服,衬砌管片承载力急剧下降。衬砌管片开裂主要在管片环的上部,应该重点加强承受上部土压力的管片强度,初始裂缝与混凝土有密切关系,应该重点加强上部混凝土的强度或在两侧螺栓孔中间添加钢纤维以加强。
There are a lot of problems with crack on shield lining segment during its assembly and use,through the study of the loading on the lining segment,the factors affecting the cracks are analyzed to provide a technical support for optimal design of the segment.The normal shield lining（diameter of vertical steel bar is 18mm from HRB335 steel） and the reinforced shield lining segments（diameter of vertical steel bar is 22mm from HRB335 steel） were used and the cracks on both segments were compared to analyze the factors affecting the crack of lining segment.The results show that the initial crack is impacted only by the concrete and the steel plays an insignificant role.When the load increases,the depth of crack becomes greater.The damage of concrete is more serious during segment failure.Serious cracks are near the bolt hole in the center of the lining segment;this section is mainly exposed to bending moment.The basic non-cracking area is at both sides of the bolt to the joints,this section is mainly affected by the axial force.The steel bar yields in the outer protective while the concrete layer is destroyed.The capacity of lining segment is sharply declined.Conclusions are drawn from the study that lining cracks mainly appear in the upper part of the segment ring.Strengthening the upper part of segment to withstand the earth pressure should be focused.The initial crack is closely related to the concrete.Strengthening the concrete at upper part of segment or the area in the middle of the bolt hole on both sides by adding steel fiber are necessary.
出处
《地下空间与工程学报》
CSCD
北大核心
2011年第4期676-680,共5页
Chinese Journal of Underground Space and Engineering
基金
沈阳市科技局
财政局资助项目(2007GX-47)
