基于三点修正双曲线法的建筑垃圾填筑路基沉降预测
Subsidence prediction of construction waste subgrade filled based on three-point modified hyperbolic method

为了推广建筑垃圾在高速公路路基填筑中的再应用，保证高速公路修筑和运营质量，以西咸（西安―咸阳）北环线建筑垃圾填筑路基试验段为工程依托，在分析现场实测数据的基础上，研究建筑垃圾填筑路基的沉降特点；然后以计算结果误差平方和、拟合系数、最终沉降量的预测值为评判标准，研究双曲线法、三点法的详细计算步骤，针对西咸北环线建筑垃圾填筑路基沉降观测数据存在波动的特点，对比分析每种方法的优缺点及适用性；并基于三点法的选点思路，在现场实测沉降曲线上选择3个适当的点作为预测样本，对双曲线法进行修正，提出一种精准预测建筑垃圾填筑路基沉降的三点修正双曲线模型，对比现场实测数据与三点法、双曲线法的预测结果，研究三点修正双曲线法在建筑垃圾填筑路基沉降预测中的预测成效、适用性和优势；为避免人为选点误差，进一步提高三点修正双曲线法的预测精度，对比不同时间起点t1、时间间隔Δt的沉降预测结果，探求三点修正双曲线法的选点限制范围。研究结果表明：建筑垃圾填筑路基具有沉降量小、沉降波动大的特点；三点法和双曲线法不能简单、有效、准确地对建筑垃圾填筑路基沉降进行预测，三点修正双曲线法克服了实测数据波动造成的影响，与现场实测曲线吻合良好，对建筑垃圾填筑路基的沉降预测效果优于三点法和双曲线法；三点修正双曲法的预测精度受选点的影响很大，选点不合适会出现误差平方和过大、最终沉降值预测不准确等情况；当Δt相同时，随着t1增大，预测精度和拟合性都在降低，当t1取为路基填土期完成，稳定期开始时，预测精度最高；当t1相同，Δt较小时，预测值曲线偏离实测曲线，误差较大，Δt越大，沉降预测曲线越接近现场实测曲线，因此建议Δt不少于60 d；为避免出现预测异常，模型中选取的3个点S1、S2、S3要能反映实测曲线的发展趋向，应满足S1
In order to promote the reuse of construction waste in highway subgrade filling and ensure the quality of highway construction and operation, relied on the project of construction waste filling subgrade test section in North Loop of Xi’an to Xianyang Highway and based on the analysis of on-site measured data, subsidence characteristics of subgrade filling by construction waste were studied. Sum of squared error of calculated results, fitting coefficient and final subsidence of predicted values were taken as evaluation criteria, detailed calculation steps of hyperbolic method and three-point method were studied. According to the fluctuation characteristics of observation data collected in the construction project, advantages, disadvantages and applicability of each method were compared and analyzed. Based on selecting points ideas of three-point method, three appropriate points were selected as predicted sample in on-site measured subsidence curve to modify hyperbolic method, and a three-point modified hyperbolic method was provided to accurately predict the subsidence of construction waste subgrade filling. By comparing the on-site measured data, the prediction results of hyperbolic method and three-point method, the prediction effect, applicability, advantages and disadvantages of three-point modified hyperbolic method in subsidence prediction of construction waste filling were studied. In order to avoid the error created by artificial selecting points and further improve prediction accuracy of three-point modified hyperbolic method, the limited range of selecting points were explored by comparing the prediction results of different starting times t1 and time interval Δt. The results show that construction waste subgrade filling has the characteristics of small subsidence value and re