重庆丘陵山区农业机械参数及机耕道路面研究

Parameters of Agricutural Machinery and Rural Field Road Design in Hilly Region in Chongqing

针对重庆丘陵山区农村机耕道(田间道)不适应农业机械化发展需要的问题,以重庆市合川区大石镇作为研究对象,运用荷载和温度疲劳理论对农村机耕道路路面进行设计优化。农业机械标准轴载为145次/d,标准轴载累计作用次数为112.82万次;当农村机耕道路水泥混凝土路面厚度为0.18 m时,荷载疲劳应力(σpr)和温度疲劳应力(σtr)值分别为3.75,0.32 MPa,rr(σpr+σtr)值为4.36 MPa,小于普通混凝土面层的弯拉强度标准值fr(4.5MPa)。当厚度为0.16 m时,rr(σpr+σtr)值为4.86 MPa,大于普通混凝土面层的弯拉强度标准值fr。因此,农村机耕道路水泥混凝土路面面层最小设计厚度为0.18 m,最大厚度为0.22 m,基层采用0.18 m水泥稳定粒料、0.20 m块石垫层,该路面结构可以有效承受设计基准期内农业机械荷载和温度疲劳应力的综合作用。

The rural field road in Chongqing hilly region could not adapt to the development of agricutural mechanization.Taking Dashi Town in Hechuan County as the research object,in this paper the pavement load fatigue stressand temperature fatigue stress theories were applied to optimize the pavement design of rural field road.The research result showed that the standard axle load of agriculture machine was 145 times per day and the cumulative action number of the standard axle load was 1 128 200.When the concrete pavement thickness of the rural field road is 0.18 m,the research for the pavement showed that the load fatigue stress（σpr） and the temperature fatigue stress（σtr） are 3.75,0.32,respectively,the numerical value rr（σpr＋σtr） is 4.36,which is less than the flexural tensile strength.When the concrete thickness is 0.16 m,the load fatigue stress（σpr） and the temperature fatigue stress（σtr） are 4.42,0.12,respectively,and rr（σpr＋σtr） is 4.86,which is beyond the flexural tensile strength.Consequently,it is concluded that the least thickness of cement concrete is 0.18 m,and the maximum is 0.22 m.At the same time,cement stabilized aggregates with size of 0.18m are used as the base material of road and rubbles with size of 0.20 m are used as the cushion material.So the road structure could preferably bear the comprehensive action from the load and temperature fatigue stress.