沥青路面惰性弯沉点的选取及土基模量的反演

Selection of Inertial Point for Asphalt Pavement and Backcalculation Method of Subgrade Modulus

摘要:

水泥混凝土路面存在弯沉几乎不随模量变化而变化的惰性弯沉点，并可用于反算水泥混凝土路面结构模量.为了使理论弯沉盆与实测弯沉盆相匹配，将刚性下卧层引入到理论弯沉盆的计算当中，经过大量的弯沉盆计算发现，沥青路面惰性弯沉点的选取较为困难，为此提出了一种基于均方根误差最小准则的惰性弯沉点选取方法，并将其应用于土基模量的反演中.在基于惰性弯沉点的土基模量反算中发现基层模量的大小对土基模量反演的精度有比较大的影响，并分别回归出针对柔性基层和半刚性基层的路面结构信息与惰性点参数的关系.选取不同的路面结构进行土基模量反演，理论上论证回归公式的精度，用实测弯沉盆进行模量反算，并与国内外其他反算程序比较，验证了基于惰性弯沉点的土基模量反演方法的精度和可靠性.

Abstract:

It is realized that there exists a point called the inertial point in the pavement deflection basin whose deflection does not vary with the modulus of the upper layer, provided that the subgrade modulus and the upper layer thickness remain unchanged in cement concrete pavement. In order to make the theoretical deflection basin and measured deflection basin match each, the writer of this paper takes the rigid substratum into the calculation of theoretical deflection basin. As a result of a significant amount of calculation, the writer found it’s very difficult to get inertial point in asphalt pavement structure. Since that, the writer developes a new method of selecting inertial point based on smallest criterion of root mean square error and applies it to the back calculation of the subgrade modulus. It is found that the value of base modulus contributes more to the precision of subgrade modulus backcalculation and the writer draws a conclusion about the relationship between the inertial point parameters and the structure information on both flexible base and semi rigid base. The writer demonstrates the precision of the induction formula theoretically through the back calculations in different pavement structures, the precision and the reliablility of subgrade modulus backcalculation method based on inertial point using measured deflection basin are verified by a comparative study of the backcalculation programs at home and abroad.