摘要
研究目的:隧道二次衬砌裂缝是隧道的严重病害之一,给施工质量和运营安全带来不利影响。本文结合某客运专线所处环境及混凝土施工中出现的问题进行分析,对二次衬砌混凝土的裂缝成因进行探讨,提出裂缝产生的几种关键影响因素,并对预防裂缝产生及裂缝的修补提出建议。研究结论:产生裂缝的原因多种多样,引起隧道二次衬砌贯穿裂缝从干缩裂缝开始,气温下降可导致裂缝继续发展,自重、外界施工扰动或围岩压力下不均匀沉降也导致裂缝继续发展。通过研究提出:混凝土掺加外掺料和高效减水剂,提高混凝土抗裂性能;二次衬砌应与隧道开挖面拉开距离,减少开挖爆破对二次衬砌混凝土的扰动;并采用洞口密封保温措施预防;混凝土仰拱与二次衬砌施工缝对缝施工,防止仰拱施工缝变形对二次衬砌造成危害。
Research purposes：Crack in the secondary lining of tunnel is one of the worst tunnel diseases and it can bring the negative effects to the safety,quality and even operation of tunnel.This paper analyzes the construction environment of one passenger dedicated line and the problems encountered during concrete construction,discusses the cause for the cracks in the secondary lining,puts forward the the key factors for forming the cracks and makes proposals on crack prevention and crack repairing.Research conclusions：There are many factors that can cause the cracks.The shrinkage crack is the preliminary causes for the through crack in the secondary lining of tunnel.The temperature drop can cause the crack to develop into larger one.And the self-gravity,the construction disturbance or the uneven settlement under rock mass pressures can cause the crack continuous developing.The study shows the capacity of crack-resistance of concrete can be improved if the concrete is mixed with external material and high-efficient water-reduction agent.The secondary lining should be kept a certain distance from the excavated section to reduce the disturbance of excavation blast to the concrete of secondary lining.The tunnel portal should be enclosed for insulation.The joint-to-joint construction should be conducted to the concrete converted arch and the secondary lining for prevention of the harm of crack deformation caused by the converted arch construction to the secondary lining.
出处
《铁道工程学报》
EI
北大核心
2010年第7期60-63,共4页
Journal of Railway Engineering Society
关键词
裂缝
温度
荷载
变形
施工缝
内应力
高性能混凝土
crack
temperature
load
deformation
construction joint
internal stress
high-performance concrete
