超厚水泥稳定碎石基层室内试验及数值模拟分析

为了研究细观层次下碎石混合料中裂纹的产生发展及应力应变分布情况,以水泥碎石基层为研究对象,依托望谟至贞丰公路超厚宽幅水泥稳定碎石基层施工项目,进行原材料选择与检测。首先利用规划求解法进行混合料配合比设计得出最优配比;然后进行室内击实试验获得最大干密度与最优含水量,并进行无侧限压缩试验获得无侧限抗压强度,再利用灰色关联法获得原材料对混合料7 d无侧限抗压强度的关联度大小;最后利用有限元分析软件ANSYS对水泥碎石试件在单轴受压及抗折情况下碎石混合料中裂纹的产生、扩展及贯通的全过程以及应力分布情况进行模拟,通过与无侧限抗压强度试验结果对比,证明了此数值模拟方法的可靠性和合理性。结果显示:随水泥剂量的增加,水泥稳定级配碎石混合料最佳含水量及最大干密度随之增加;混合料水泥剂量与水泥碎石基层混合料7 d无侧限抗压强度之间的关联度4.75 mm碎石集料筛孔处的通过率混合料含水量;竖向受压过程中随着水泥剂量的增加,混合料试件破坏时的最大位移逐渐增加,且应力集中更加明显,骨料的破坏程度随之增大;混合料抗折破坏过程首先始于大粒径碎石骨料的水泥与碎石骨料界面过渡区,然后逐渐扩展,水泥剂量越大,混合料抗折能力越强,但应力集中越明显。

In-door experiment and numerical-simulative analysis of super thick cement-stabilized crushed stone base course

In order to study the development and stress-strain distribution of the crack in crushed stone mixture under meso-level， the raw materials are selected and tested through relying on the project of the construction of super thick and wide cement-stabilized crushed stone base course of Wangmo to Zhenfeng Highway by taking the cement-stabilized crushed stone base course as the study object，and then the optimal mixing ratio of the mixture is obtained through the design of it by means of programming solving method. Afterwards，the relevant in-door compaction experiment is made，and then the maximum dry density and optimal water content are obtained，while the unconfined compressive strength is also obtained from the relevant unconfined compression test. The correlation degree of the raw materials to the 7-days unconfined compressive strength of the mixture is obtained with the grey correlation method. Finally，the whole processes of the generation，propagation and penetration as well as the stress distribution of the crack in the crushed stone mixture of the cement-crushed stone specimen under the uniaxial compression and anti-bending condition are simulated with the finite element analysis software—ANSYS. Through comparing with the result of the unconfined compression strength test，the reliability and reasonability of this numerical simulation method are verified. The study result shows that both the optimal water content and the maximum dry density of the cement stabilized-graded crushed stone mixture are increased along with the increase of the cement content，i. e. the correlation degree between the cement content of the mixture and the 7-days unconfined compressive strength of the mixture of the cement-crushed stone base course ＞ the passing rate of the crushed stone aggregate through the sieve hole of 4. 75 mm ＞ the water content of mixture，while the maximum displacement of the specimen of the mixture during destruction is gradually increased along with the increase of the cement content during the vertical compression; moreover，the stress concentration is more obvious along with the increase of the destructive degree. The destruction process initially starts from the interfacial transition zone between cement and crushed stone aggregate with large particle size，and then is gradually expanded，while the lager the cement content is，the stronger the bending resistance of the mixture is to be，but the more obvious the stress concentration is to be as well.