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基于有限元软件KENSLABS,构建了水泥混凝土路面轮载损伤计算模型,引入地基季节调整系数与零养护疲劳准则,分析了土基模量整体削弱对路面疲劳开裂指数的影响,探讨了当量轴载系数与多轴通过一次的计算次数对土基模量的依赖性,研究了不同土基模量下板厚、水泥混凝土抗弯拉强度、单轴轴重、单轴每日重复作用次数等核心路面设计参数与路面开裂指数的关系。研究结果表明:水泥混凝土路面疲劳开裂指数随着地基季节调整系数的减小而增大,增大速度随地基季节调整系数的减小而加快,当地基季节调整系数从1.0减小为0.8和从0.4减小为0.2时,在单轴、双轴和三轴荷载作用下,路面开裂指数分别增大了2.8、2.9、1.5倍和49.8、269.0、1 351.4倍;当量轴载系数与多轴通过一次的重复计算次数受到板厚与土基模量的影响,在土基模量为60 MPa,板厚为15cm或35cm时,单轴荷载比双轴荷载更易产生损伤,双轴荷载比三轴荷载更易产生损伤,在土基模量为20MPa,板厚为15cm时也是如此,但在土基模量为20MPa,板厚为35cm时,结论则与前相反;水泥混凝土路面疲劳开裂指数随着面板厚度、水泥混凝土抗弯拉强度、单轴轴重、单轴每日重复作用次数而改变的幅度与土基模量直接相关,当土基模量为20、60 MPa时,面板厚度从21cm增加到25cm,疲劳开裂指数分别减小1.18×10、1.18×10~(-2),当混凝土抗弯拉强度从4.0 MPa增大到4.4 MPa,疲劳开裂指数分别减小1.28、2.20×10~(-3),当单轴轴重从80kN增大到160kN时,疲劳开裂指数分别增大5.48、7.36×10~(-3),当单轴荷载每日重复作用次数从50增加到90时,疲劳开裂指数分别增大2.05×10-1、5.07×10~(-4);增设厚度为15cm的水泥稳定基层后,设定工况下的路面疲劳开裂设计寿命增加3.42年;在提高土基模量的同时,宜优先考虑适当增加板厚,严禁超载,设置水泥稳定基层等措施,可以控制水泥混凝土路面受轮载作用的疲劳开裂破坏。
Based on the finite element software KENSLABS, the calculation model of wheel-mounted damage on cement concrete pavement is built. The seasonal adjustment coefficient and zero-maintenance fatigue criterion are introduced. The influence of the overall weakening of the soil modulus on the fatigue cracking index is analyzed. With the calculation of the number of times through which one axis passes through, the dependence of the modulus of the soil foundation is studied. The core pavement such as plate thickness under different modulus of foundation, bending strength of concrete, uniaxial axial load, Relationship between Design Parameters and Pavement Cracking Index. The results show that the fatigue crack initiation index of cement concrete pavement increases with the decrease of seasonal seasoning coefficient, and the increase speed increases with the decrease of seasonal seasonality adjustment coefficient. The seasonal seasonally adjusted coefficient decreases from 1.0 to 0.8 and from 0.4 was reduced to 0.2, the pavement crack index increased by 2.8, 2.9, 1.5 times and 49.8, 269.0 and 1 351.4 times respectively under the uniaxial, biaxial and triaxial loads; the equivalent axial load coefficient and multiaxial pass The number of repeated calculations is affected by the thickness of plate and the modulus of subgrade. When the modulus of foundation is 60 MPa and the thickness of plate is 15 cm or 35 cm, the uniaxial load is more likely to be damaged than the biaxial load. The load is more likely to cause damage, as is the case when the modulus of the soil is 20 MPa and the thickness is 15 cm. However, the conclusion is the same when the modulus of the soil is 20 MPa and the thickness of the plate is 35 cm. The fatigue cracking index of cement concrete pavement The thickness of the panel, the flexural strength of concrete, the uniaxial axial weight and the number of repeated single-axis repeated actions are directly related to the modulus of the soil. When the modulus of the soil foundation is 20 and 60 MPa, the panel thickness changes from 21cm Increased to 25cm, the fatigue crack index decreased by 1.18 10,1.18 × 10 ~ (-2). When the flexural tensile strength of concrete increases from 4.0 MPa to 4.4 MPa, the fatigue cracking index decreases by 1.28 and 2.20 × 10 -3, respectively. When the uniaxial axial weight increases from 80 kN Increasing to 160kN, the fatigue cracking index increased by 5.48,7.36 × 10 ~ (-3), respectively. When the uniaxial load per day increased from 50 to 90, the fatigue cracking index increased by 2.05 × 10-1 , 5.07 × 10 ~ (-4). After adding the cement stabilized base with the thickness of 15cm, the fatigue life of the pavement under the set conditions increases by 3.42 years. When increasing the modulus of the soil foundation, Thick, non-overload, set the grass-roots and other measures to stabilize the cement, concrete pavement can be controlled by the fatigue effect of fatigue cracking.