根据旧桥加固原则确定套拱法内套拱圈厚度。内套拱组合加固法是指在原拱圈下部增设一道协助原拱圈受力的新拱圈,即紧贴原拱圈底部用石砌一道新拱圈或用钢筋混凝土浇注一道新拱圈,在形式上形成了原拱圈内套一个新拱圈,从而利用原拱圈与其下增设的新加筑拱圈共同受力的组合加固方法。这种方法主要适用于桥下净空或根据水文地质资料桥下泄水面积容许缩小时。本文主要阐述如何根据旧桥加固原则确定内套拱圈拱厚度。 According to the principle of strengthening the old bridge to determine the thickness of arch sleeve arch ring method. Inner sleeve arch combination reinforcement method is to add a new arch ring in the lower part of the original arch ring to assist the force of the original arch ring, that is, a new arch ring is placed close to the bottom of the original arch ring or a new arch ring is made by using reinforced concrete Form a new arch ring within the original arch ring, thus using the combination of the original arch ring and the new additional arch ring added under the force of the combined reinforcement method. This method is mainly applicable to the bridge under the headroom or according to the hydrogeological data bridge under the drainage area allowed to shrink. This paper mainly elaborates how to determine the thickness of inner arch arch ring according to the principle of strengthening the old bridge.