Mackiewicz Piotr, Krawczyk Bartłomiej
Faculty of Civil Engineering, Wrocław University of Science and Technology, 50-370 Wrocław, Poland.
Materials (Basel). 2022 Aug 17;15(16):5646. doi: 10.3390/ma15165646.
This article analyzes the results of testing the subgrade and the lower layers of the pavement structure with the light weight deflectometer at a load of 0.1 and 0.15 MPa. It is shown that, with layer systems with an equivalent layer modulus lower than 80 MPa, significant nonlinear phenomena occur at a load of 0.15 MPa. In this situation, the identification of a reliable replacement module, a commonly used test method, at a load of 0.1 MPa, is not appropriate-it significantly overestimates the value of the modules (even by 34%), which in turn translates into a significant overestimation of the fatigue life of the structure. In a situation where intensive exploitation of the lower layers of the pavement structure is planned before the final layer arrangement is made, it is required to apply test loads corresponding to the stress conditions occurring in these layers of the structure. Such a situation takes place under the influence of technological (construction) or temporary traffic (substitute, e.g., by-pass) during construction. In order to verify the above assumptions, numerical calculations (FEM) were carried out in the elastic model for layered structures with replacement modules determined in field tests. It was found that, especially in the case of low-bearing layer systems, it is necessary to use correction factors for modules determined with a dynamic plate at a load of 0.1 MPa. Taking into account the corrected values of the modules will allow to correctly determine the change in the durability of layers at the construction stage and in the subsequent operation of the final pavement structure.
本文分析了采用轻型弯沉仪在0.1和0.15兆帕荷载下对路基和路面结构下层进行测试的结果。结果表明，对于等效层模量低于80兆帕的层体系，在0.15兆帕荷载下会出现显著的非线性现象。在这种情况下，采用常用的测试方法，即在0.1兆帕荷载下确定可靠的替代模量，是不合适的——它会显著高估模量值（甚至高估34%），这反过来又会导致对结构疲劳寿命的显著高估。在计划在铺设最后一层之前对路面结构下层进行密集开采的情况下，需要施加与结构这些层中出现的应力条件相对应的测试荷载。这种情况在施工期间受技术（施工）或临时交通（例如替代、绕行）影响时会发生。为了验证上述假设，针对在现场测试中确定了替代模量的层状结构弹性模型进行了数值计算（有限元法）。结果发现，特别是对于低承载层体系，有必要对在0.1兆帕荷载下用动态平板确定的模量使用修正系数。考虑模量的修正值将有助于正确确定施工阶段以及最终路面结构后续运营中层耐久性的变化。
