点击次数：

所属单位：航空学院

发表刊物：Jiaotong Yunshu Gongcheng Xuebao

摘要：By the laboratory and field cement-stabilized macadam base crack monitoring tests, the relationship between sensing fiber strain and crack width, crack propagation rule in early stage of semi-rigid base, and crack growth rate were researched based on the distributed BOTDA fiber monitoring technology. Research result shows that when the crack widths are 3, 6 and 9 mm, the strains measured by the sensing fiber encapsulated with polyurethane are 5.9×10-3, 7.7×10-3, and 10.3×10-3, respectively, the strains measured by the sensing fiber encapsulated with metal matrix are 1.5×10-3, 1.6×10-3, and 2.1×10-3, respectively, and the fiber strain rises with the increase of crack width. When the crack width is 9 mm, the strains measured by the sensing fibers encapsulated with polyurethane and metal matrix are 33.2 and 6.8 times as big as the average value measured by the interval fixed fiber armored with aluminum alloy respectively, so the sensing fibers encapsulated with polyurethane and metal matrix performs better for crack monitoring. In field experiment, in 13 d after construction, 3 micro cracks were found at 80 m long road section, and the largest temperature difference is 2.1℃ during this period, which indicates that the cracks in the base generate and develope mainly in the first month and the dry shrinkage cracks are dominant. The dry shrinkage stress is the main influence factor of crack generation and crack spacing. In 20, 77 and 139 d after construction, the temperatures at the bottom surface of base layer are 10.3℃, 2.5℃ and 9.4℃, respectively, and the corresponding strains measured at the bottom surface of base layer at crack location of K24+656 are 4.2×10-4, 9.5×10-4and 4.3×10-4, respectively. No new cracks emerge in base layer in 139 d, which indicates that the influence of thermal shrinkage stress on early crack spacing is very less, and the thermal shrinkage stress mainly affects the crack width. The thermal shrinkage cracks basically appear at the position where the dry shrinkage stress displays peaks in the dry shrinkage phase. When the upper and lower base layers were constructed continuously, the positons of cracks of top surface and bottom are consistent. Hence, the transverse cracks in cement-stabilized macadam base are always penetrating cracks. Furthermore, the crack growth rate on the top surface is 3.8 and 2.8 times the values at the middle and bottom positons, respectively, so the crack growth rate on the top surface is biggest. © 2017, Editorial Department of Journal of Traffic and Transportation Engineering. All right reserved.

ISSN号：1671-1637

是否译文：否

发表时间：2017-02-01

合写作者：Geng, Ren-Shan,Sheng, Yu-Xiang,An, Ping,Jin, Pei-Pei

通讯作者：高俊启