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1 引言隧洞混凝土衬砌出现裂缝的原因是多方面的,结构物设计不合理、隧洞的地质断层与围岩破碎带移动、混凝土在水化过程中温度应力的作用、结构物里的钢筋锈蚀、混凝土施工工艺的不规范(包括水灰比不合理)、外加物掺量不足、热水泥运到后不静置一段时间、粗骨料与细骨料质量差、碱骨料过多等等,都可以引起表层裂纹直至深层,严重者可造成贯穿性裂缝。水利工程在施工过程中出现裂缝宽度在规范允许范围内的是客观存在,但在施工过程中改进施工工艺、科学地进行配比、控制原材料进厂、施工工序按设计和规范要求、及时养护、及时进行地质预报等则能将衬砌裂缝出现的机率控制到最低限度,这是给水利工作者一个长期艰巨的研究课题。在盘石头水库项目隧洞混凝土衬砌的施工过程中,进行裂缝预防,根据以往隧洞施工过程中出现的情况以及采取的预防措施作一总结,供水利工作者参考。
1 Introduction Tunnel cracks occur for many reasons, the structural design is not reasonable, the tunnel fault and the surrounding rock fracture movement, the role of concrete in the hydration process of temperature stress, the structure of steel corrosion, concrete Non-standard construction techniques (including water-cement ratio is not reasonable), lack of admixture, hot cement after not settling for a period of time, the poor quality of coarse aggregate and fine aggregate, alkali aggregate too much, etc. Can cause surface cracks until deep, severe cases can cause through cracks. In the construction process, the width of cracks in the water conservancy project is an objective existence within the allowable range of the standard, but the construction technology is improved in the construction process, the ratio is scientifically controlled, raw materials are input into the factory, the construction process is timely cured according to the design and specification requirements, It is a long-term and arduous research project for water conservancy workers to control the probability of occurrence of lining cracks timely by carrying out geological forecasting. In the process of construction of tunnel concrete lining of Pan Shitou Reservoir Project, cracks prevention is carried out. Based on the situation occurred in the past tunnel construction and preventive measures taken, a summary is made for the reference of water conservancy workers.