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本文以线弹性层状体系理论为基础,分析了半刚性基层沥青路面设计中的若干问题:(1)设计指标;(2)计算状态——设计中应采用的最不利环境条件;(3)半刚性基层沥青路面的结构组合。 分析结果表明:在常用路面结构中,路表弯沉与路基表面的压应变或压应力呈半对数直线关系,采用路表弯沉值这项指标已足以控制路基表面的压应变或压应力。关于弯沉指标的计算状态,对于面层较薄的道路结构仍然以路基湿软季节为准;对于较厚的面层,必须重视半刚性基层模量大于面层,尤其是高温时的反应。 关于各结构层的永久变形,作了初步计算和分析。为了减少路面的永久变形量,以减薄面层厚度,加厚和加强基层及路基为宜。 关于面层底面的应力,当层间接触面连续时,面层有可能处于受压状态,尤其是半刚性基层模量大于面层或高温时;当面层与基层接触面无摩阻力时,其底面则处于受拉状态,拉应力的大小主要与面层厚度及面层与基层的模量比E_2/F_1有关。为减少拉应力,最好是减薄面层厚度,采用模量不高于1000Mpa的半刚性材料。计算结果表 明:加强路基、选用刚度适当的半刚性材料,其厚度在H/δ=3.0左右,既能减少面层的永久变形及其底面的弯拉应力,同时又不使基层底面的拉应力有明显的提高。 关于基层弯拉指标的计算状态,对于面层较薄的道路结构仍
In this paper, based on the theory of linear elastic stratified system, some problems in the design of semi-rigid base asphalt pavement are analyzed: (1) design indexes; (2) state of calculation- the most unfavorable environmental conditions to be adopted in design; (3) Structural Combination of Semi - rigid Base Asphalt Pavement. The analysis results show that in the common pavement structure, the deflection of road surface and the compressive stress or compressive stress on the surface of roadbed are semi-logarithmically linear. The index of road surface deflection is enough to control the compressive strain or compressive stress . For the calculation of deflection index, the roadbed with thinner surface is still based on the wet season of subgrade. For thicker surface, the modulus of semi-rigid base must be greater than that of the surface layer, especially at high temperature. For each layer of the permanent deformation, made a preliminary calculation and analysis. In order to reduce the permanent deformation of the road to reduce the thickness of the surface layer, thickening and strengthening the grassroots and roadbed is appropriate. As for the stress of the bottom surface, the surface layer may be under compression when the contact surface between layers is continuous, especially when the modulus of semi-rigid base layer is larger than that of the surface layer or the high temperature. When there is no friction between the surface layer and the base layer, The bottom is in tension, the size of the tensile stress is mainly related to the thickness of the surface layer and the modulus E_2 / F_1 of the surface layer and the base layer. To reduce tensile stress, it is best to reduce the thickness of the surface layer, using a modulus of not more than 1000Mpa semi-rigid material. The calculation results show that the strengthening of roadbed, the selection of semi-rigid materials with appropriate stiffness, the thickness of H / δ = 3.0 or so, both to reduce the permanent deformation of the surface and the bottom of the bending stress, without the underlying tensile stress Significantly improved. On the calculation of grass-roots bending indicators, for the surface layer of the road structure is still thin