進行鋪面結構的力學分析時，一般把鋪面簡化成二維的問題進行分析以減少計算的複雜性。然而實際的鋪面結構卻是一個三維的問題，因此建立一個三維的有限元素鋪面模型，可以更加適切地描述真實鋪面的情況。 本研究主要探討鋪面在不同的斷面，及使用不同的材料情況下，重車對路基土壤頂端壓應變和瀝青面層底部張應變之影響。針對設於中央大學的兩個試驗斷面，以商用軟體ABAQUS有限元素數值分析程式，建立三維有限元素鋪面模型，分別以線性及非線性分析對軸載 重下鋪面結構之反應進行探討。採用不同的軸重及接觸胎壓施加於柔性鋪面上，考慮基層及路基土壤回彈模數之非線性行為，擷取道路斷面下最大之壓應變和張應變進行分析。 結果顯示在雙軸載重下，以傳統二維疊加方法分析柔性鋪面所得之反應，於面層底部張應變及路基土壤頂端壓應變均較三維分析結果有高估現象，因此在多軸載重下之鋪面分析，使用三維有限元素分析確有必要。而比較柔性鋪面線性與非線性分析，所得的結果具有一定程度的差異。此外，接觸胎壓對面層底部張應變之影響較大，軸重則對路基頂端壓應變之影響較大。當低軸重下隨接觸胎壓之提高，將使軸重當量因子有明顯的提高，此時軸重當量因子由面層底部張應變控制，而隨著載重的提高，軸重當量因子則逐漸由路基頂端壓應變所控制。 Conventionally, the structural analyses of flexible pavement are limited to two-dimensional, in order to reduce the complexity. However, in a practical sense, the structural behavior of flexible pavement under multiple wheel loads is really a topic of three-dimension. Hence, in order to better describe the physical pavement conditions, it is necessary to develop a three-dimension finite element model. This study focuses on effects of the tensile strain at the bottom of the surface layer and the compressive strain at the top of the subgrade soil caused by heavy vehicles on different cross-sections of flexible pavement. This study uses the well-developed software, ABAQUS, to develop a pavement analysis model using three-dimensional finite element method. The study also explores the linear and nonlinear materials for the two testing pavement sections in the campus of National Central University. The results revealed that the pavement response using linear and nonlinear analysis can be somewhat different. The tire contact pressure has a lager influence on the tensile strain at the bottom of surface layer. On the other hand, the axle load has a greater effect on the compressive strain at the top of subgrade. In addition, increasing the contact pressure under low axle loads cause significant increase in the equivalent axle load factor. Meanwhile, the equivalent axle load factor is controlled by the tensile strain at the bottom of the surface layer; and with the increase in axle load, the equivalent axle load factor will then be controlled by the compressive strain at the top of the subgrade soil.
