基于混凝土水化热的灌注桩成桩质量评价方法及应用

Quality evaluation method of cast-in-place pile based on heat of concrete hydration and its application

针对如何基于灌注桩水化热温度场准确评价桩身质量的问题,利用与桩身横截面中心径向距离大于0.5倍桩半径范围内,混凝土水化热温度随径向距离的变化近似线性的特征,建立根据钢筋笼上对称两测点的水化热温度计算钢筋笼偏位的方法。结合缺陷灌注桩的水化热仿真分析,系统分析缺陷几何特征和热工参数变化对灌注桩水化热温度场的影响规律,提出根据沿钢筋笼主筋布置水化热温度测点获得的温度-深度曲线特征,判断缺陷存在并分析缺陷空间分布位置的方法。结合现场试验及与低应变、跨孔超声波检测结果的对比,验证了该方法的可行性。

Aiming at the problem of evaluating the quality of the pile body accurately based on the temperature field of the hydration heat of the cast-in-place pile,we use the characteristics of the concrete hydration heat temperature changing approximately linear with radial distance(from the center of the pile cross-section)within the range of the radial distance greater than 0.5 times the pile radius,and build the method for calculating the deviation of the reinforcement cage based on the temperature of two symmetrical measuring points on the reinforcement cage.Combining with the simulation analysis of the hydration heat of the defective pile,we systematically analyze the influence of the geometric characteristics of the defect and the change of thermal parameters on the temperature field,and propose the method for judging the presence of defects and analyzing their spatial distribution position based on the characteristics of the temperature-depth curve obtained from temperature measurement points along the main reinforcements.Combining field tests and comparison with low-strain and cross-hole ultrasonic testing results,we verify the feasibility of the method.