Subsidence prediction of construction waste subgrade filled based on three-point modified hyperbolic method(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2017年02期
- Page:
- 1-8
- Research Field:
- 道路工程
- Publishing date:
Info
- Title:
- Subsidence prediction of construction waste subgrade filled based on three-point modified hyperbolic method
- Author(s):
- WANG Hai-ying; CHANG Xiao; RUAN Qi; LU Dong-yuan
- Key Laboratory of Road Construction Technology and Equipment of Ministry of Education, Chang’an University, Xi’an 710064, Shaanxi, China
- Keywords:
- road engineering; construction waste filling; subgrade settlement prediction; three-point modified hyperbolic method; limited range of selecting point
- PACS:
- U416
- DOI:
- -
- Abstract:
- 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 relatively large fluctuations. Three-point method and hyperbolic method cannot simply, effectively and accurately predict the subsidence of construction waste subgrade filling, while three-point modified hyperbolic method can not only overcome the influence caused by fluctuation of the on-site measured data, but also has good agreement with the on-site measured curve. Its prediction performance is better than the other two methods. The prediction accuracy of three-point modified hyperbolic method is highly affected by the selecting points, sum of squares error is too large and prediction of final subsidence value is not accurate with improper collocation. When time interval is same, accuracy and fitness of the prediction reduces with the increase of starting point. When the starting time t1 is selected after subgrade filling period completed and before its stable period began, prediction accuracy is the highest. With the same starting time t1 and smaller time interval Δt, the predicted value deviates from the on-site measured curve and the error is bigger. On the contrary, the larger the time interval, the closer the subsidence prediction curve is to the on-site measured curve. Therefore, the time interval Δt is suggested to no less than 60 d. In order to avoid the abnormal prediction, the selected points S1, S2, S3 should reflect the development trend of the on-site measured curve, which should meet S1
Last Update: 2017-04-07