土基模量对水泥混凝土路面轮载疲劳开裂损伤的影响
发布时间：2019-05-19 12:55
【摘要】：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。
[Abstract]:Based on the finite element software KENSLABS, the calculation model of wheel load damage of cement concrete pavement is constructed. The seasonal adjustment coefficient of foundation and zero maintenance fatigue criterion are introduced, and the influence of the overall weakening of soil foundation modulus on the fatigue cracking index of pavement is analyzed. The dependence of equivalent axial load coefficient and multi-axial calculation times on soil foundation modulus is discussed. The slab thickness, bending tensile strength and uniaxial load of cement concrete under different soil foundation modulus are studied. The relationship between core pavement design parameters such as uniaxial daily repetition times and pavement cracking index. The results show that the fatigue cracking index of cement concrete pavement increases with the decrease of seasonal adjustment coefficient of foundation, and the increasing speed increases with the decrease of seasonal adjustment coefficient of foundation. When the seasonal adjustment coefficient of foundation decreases from 1.0 to 0.8 and from 0.4 to 0.2, the pavement cracking index increases by 2.8, 2.9, 1.5 times and 49.8269.0, respectively, under uniaxial, biaxial and triaxial loads. The repeated calculation times of equivalent axial load coefficient and multiaxial pass are affected by plate thickness and soil foundation modulus. When the soil foundation modulus is 60 MPa, plate thickness is 15cm or 35cm, uniaxial load is more likely to cause damage than biaxial load. Biaxial load is more likely to cause damage than triaxial load, the same is true when the modulus of soil foundation is 20 MPA and the thickness of plate is 15cm, but when the modulus of soil foundation is 20 MPA and the thickness of plate is 35cm, the conclusion is opposite to that of the former. The fatigue cracking index of cement concrete pavement is directly related to the modulus of soil foundation when the modulus of soil foundation is 20 and 60 MPa, with the variation of fatigue cracking index of cement concrete pavement with the thickness of face slab, the bending tensile strength of cement concrete, the uniaxial load and the number of daily repeats of uniaxial. When the thickness of panel increases from 21cm to 25 cm, the fatigue cracking index decreases by 1.18 脳 10 ~ (- 2) and 1.18 脳 10 ~ (- 2), respectively, and when the bending tensile strength of concrete increases from 4.0 MPa to 4.4 MPa, the fatigue cracking index decreases by 1.28,2.20 脳 10 ~ (- 3), respectively. When the uniaxial load increases from 80kN to 160kN, the fatigue cracking index increases by 5.48,7.36 脳 10 ~ (- 3), and when the daily repetition number of uniaxial load increases from 50 to 90, the fatigue cracking index increases by 2.05 脳 10 鈮，
本文编号：2480740
[Abstract]:Based on the finite element software KENSLABS, the calculation model of wheel load damage of cement concrete pavement is constructed. The seasonal adjustment coefficient of foundation and zero maintenance fatigue criterion are introduced, and the influence of the overall weakening of soil foundation modulus on the fatigue cracking index of pavement is analyzed. The dependence of equivalent axial load coefficient and multi-axial calculation times on soil foundation modulus is discussed. The slab thickness, bending tensile strength and uniaxial load of cement concrete under different soil foundation modulus are studied. The relationship between core pavement design parameters such as uniaxial daily repetition times and pavement cracking index. The results show that the fatigue cracking index of cement concrete pavement increases with the decrease of seasonal adjustment coefficient of foundation, and the increasing speed increases with the decrease of seasonal adjustment coefficient of foundation. When the seasonal adjustment coefficient of foundation decreases from 1.0 to 0.8 and from 0.4 to 0.2, the pavement cracking index increases by 2.8, 2.9, 1.5 times and 49.8269.0, respectively, under uniaxial, biaxial and triaxial loads. The repeated calculation times of equivalent axial load coefficient and multiaxial pass are affected by plate thickness and soil foundation modulus. When the soil foundation modulus is 60 MPa, plate thickness is 15cm or 35cm, uniaxial load is more likely to cause damage than biaxial load. Biaxial load is more likely to cause damage than triaxial load, the same is true when the modulus of soil foundation is 20 MPA and the thickness of plate is 15cm, but when the modulus of soil foundation is 20 MPA and the thickness of plate is 35cm, the conclusion is opposite to that of the former. The fatigue cracking index of cement concrete pavement is directly related to the modulus of soil foundation when the modulus of soil foundation is 20 and 60 MPa, with the variation of fatigue cracking index of cement concrete pavement with the thickness of face slab, the bending tensile strength of cement concrete, the uniaxial load and the number of daily repeats of uniaxial. When the thickness of panel increases from 21cm to 25 cm, the fatigue cracking index decreases by 1.18 脳 10 ~ (- 2) and 1.18 脳 10 ~ (- 2), respectively, and when the bending tensile strength of concrete increases from 4.0 MPa to 4.4 MPa, the fatigue cracking index decreases by 1.28,2.20 脳 10 ~ (- 3), respectively. When the uniaxial load increases from 80kN to 160kN, the fatigue cracking index increases by 5.48,7.36 脳 10 ~ (- 3), and when the daily repetition number of uniaxial load increases from 50 to 90, the fatigue cracking index increases by 2.05 脳 10 鈮，
本文编号：2480740
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