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鉆孔灌注樁在工程施工質量的常見問題及防治措施
（作者未知） 2009/6/4
（接上頁）凝土灌注過程中出現的工程施工質量問題及防治措施
1、卡管
水中灌注混凝土過程中，無法繼續(xù)進行的現象。
造成原因：初灌時，隔水栓堵管；混凝土和易性、流動性差造成離析；混凝土中粗骨料粒徑過大；各種機械故障引起混凝土澆筑不連續(xù)，在導管中停留時間過長而卡管；導管進水造成混凝土離析等。
防治措施：使用的隔水栓直徑應與導管內徑相配，同時具有良好的隔水性能，保證順利排出。在混凝土灌注時，應加強對混凝土攪拌時間和混凝土坍落度的控制。水下混凝土必須具備良好的和易性，配合比應通過實驗室確定，坍落度宜為18-22cm，粗骨料的最大粒徑不得大于導管直徑和鋼筋籠主筋最小凈距的1/4，且應小于40mm。為改善混凝土的和易性和緩凝，水下混凝土宜摻外加劑。應確保導管連接部位的密封性，導管使用前應試拼裝、試壓，試水壓力為0.6-1.0MPa，以避免導管進水。在混凝土澆筑過程中，混凝土應緩緩倒入漏斗的導管，避免在導管內形成高壓氣塞。在工程施工過程中，應時刻監(jiān)控機械設備，確保機械運轉正常，避免機械事故的發(fā)生。
翻譯：Abstract: bored piles as a result of a variety of geological conditions of adaptability, simple construction and easy-to-use input devices are generally not large, so the various types of civil construction and housing are widely used. The bored piles most of the construction project is carried out under water, the construction process can not be observed, into a pile after the acceptance of excavating can not be carried out. Construction of a part of any problems will directly affect the quality and progress of the project, and even investors to huge economic losses and bad social impact. Prevention must be in the process of drilling and underwater concrete perfusion that often appear in the course of construction quality, durability, security and quantity completion of the foundation construction mission.
Key words: Pile、Construction Quality、Prevention and control measures
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