Experimental study on the influence of freeze-thaw cycles on the anchoring performance of GFRP anchor
-
摘要:
针对季冻区春融期岩锚失效的问题, 研究了玻璃纤维(GFRP)锚杆在冻融循环作用下的锚固能力。通过设计物理模型对经历25, 50, 75冻融周期的试块进行了加载试验, 根据试验数据和破坏现象分析了GFRP锚杆在冻融后锚杆应力和承载力的变化规律。研究结果表明: 冻融循环会导致环氧树脂砂浆与混凝土的黏结性能下降, 在25, 50, 75周期后承载力损失分别为38.24%, 42.65%, 52.94%。冻融循环加速黏结材料及围岩的材料性能劣化, 荷载向内部传递加速, 使得GFRP锚杆上各点之间的应力差值逐渐减小, 锚杆应力分布比常温状态下更趋于均匀, 但材料性能的劣化导致局部破坏提前, 锚杆整体承载性能降低。研究结果可以为GFRP锚杆的工程应用提供建议。
Abstract:In view of the failure of rock anchors in spring thawing periods of seasonal freezing areas, this paper aims to investigate the anchorage ability of GFRP anchors under the action of freeze-thaw cycles.Through designing the physical model, loading tests were carried out on the test blocks experiencing 25, 50, and 75 freeze-thaw cycles.According to the test data and failure phenomena, the variation laws of the stress and bearing capacity of the GFRP bolt after freeze-thaw were analyzed.The results show that the freeze-thaw cycle will lead to a decrease in bonding performance between epoxy resin mortar and concrete. After 25, 50 and 75 cycles, the bearing capacity loss is 38.24%, 42.65% and 52.94%, respectively.The ultimate bearing capacity of the bolt decreases obviously with increasing freeze-thaw cycles. The freeze-thaw cycle accelerates the deterioration of the material properties of the bonding material and the surrounding rock. In the process, the load transfer to the interior is accelerated, leading to a reduction in the stress difference among points on the GFRP bolt, and the stress distribution of the bolt is more uniform than that at room temperature. Meanwhile, the deterioration of the material properties leads to local failure ahead of time, and the overall bearing capacity of the bolt is reduced.The research results can provide suggestions for the engineering application of GFRP anchor.
-
Key words:
- GFRP bolt /
- bolt stress /
- bearing capacity /
- freeze-thaw cycle /
- anchoring capacity
-
表 1 GFRP筋物理和力学性能
Table 1. Physical and mechanical properties of GFRP rebar
名称 参数 直径/mm 20 每米重量/(kg·m-1) 0.55 每吨米数/(m·t-1) 1 819 抗拉强度/MPa ≥500 抗剪强度/MPa ≥100 极限应变 ≥1.2 弹性模量/GPa ≥40 表 2 混凝土、砂浆材料用量
Table 2. Material consumption of concrete and mortar
种类 水泥/g 砂/g 水/g 石子/g 混凝土 595 559 256 1 309 砂浆 661 661 278 无 表 3 冻融循环过程中试件分组
Table 3. Grouping of specimens during freeze-thaw cycling
分组编号 冻融循环/周期 试件编号 A0 0 A-1 A-2 A-3 B25 25 B-1 B-2 B-3 C50 50 C-1 C-2 C-3 D75 75 D-1 D-2 D-3 -
[1] 晏智龙. FRP复合材料在土木工程中的应用[J]. 中国高新区, 2017, 23(1): 26. https://www.cnki.com.cn/Article/CJFDTOTAL-GXQZ201723023.htmYan Z L. Application of FRP composite materials in civil engineering[J]. China High-tech Zone, 2017, 23(1): 26(in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-GXQZ201723023.htm [2] 吴益平, 卢里尔, 薛阳. 基于临界状态的边坡渐进破坏力学模型分析及应用[J]. 地质科技通报, 2020, 39(5): 1-7. doi: 10.19509/j.cnki.dzkq.2020.0501Wu Y P, Lu L E, Xue Y. Application of landslide progressive failure mechanical model based on the critical stress state[J]. Bulletin of Geological Science and Technology, 2020, 39(5): 1-7(in Chinese with English abstract). doi: 10.19509/j.cnki.dzkq.2020.0501 [3] 黄少平, 晏鄂川, 尹晓萌, 等. 不同临空条件的层状反倾岩质边坡倾倒变形几何特征参数影响规律[J]. 地质科技通报, 2021, 40(1): 159-165 doi: 10.19509/j.cnki.dzkq.2021.0111Huang S P, Yan E C, Yin X M, et al. The action law of geometrical characteristic parameters in the anti-dip rock slopes under different free face condition[J]. Bulletin of Geological Science and Technology, 2021, 40(1): 159-165(in Chinese with English abstract). doi: 10.19509/j.cnki.dzkq.2021.0111 [4] 董志强, 吴刚. FRP筋增强混凝土结构耐久性能研究进展[J]. 土木工程学报, 2019, 52(10): 5-23, 33. https://www.cnki.com.cn/Article/CJFDTOTAL-TMGC201910001.htmDong Z Q, Wu G. Research progress on durability of FRP bars reinforced concrete structures[J]. China Civil Engineering Journal, 2019, 52(10): 5-23, 33(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-TMGC201910001.htm [5] 尹晓明, 王苏岩. FRP加固混凝土结构抗冻融性能研究进展[J]. 工业建筑, 2007, 31(增刊): 282-286. https://cpfd.cnki.com.cn/Article/CPFDTOTAL-OGTY200712004059.htmYin X M, Wang S Y. Research progress on freeze-thaw resistance of FRP reinforced concrete structures[J]. Industrial Construction, 2007, 31(S): 282-286(in Chinese with English abstract). https://cpfd.cnki.com.cn/Article/CPFDTOTAL-OGTY200712004059.htm [6] Zhang X Y, Ou J P. Durability experimental research on resistance of acidic, alkali, salt solutions and freeze-thaw properties of FRP Bar[J]. Journal of Wuhan University of Technology, 2007, 29(1): 33-36, 54. [7] Hutchinson A R, Hollaway L C. Environmental durability[J]. Strengthening of Reinforced Concrete Structures, 1999, 1(6): 156-182. [8] Chen Y, Davalos J F, Ray I, et al. Accelerated aging tests for evaluations of durability performance of FRP reinforcing bars for concrete structures[J]. Composite Structures, 2007, 78(1): 101-111. [9] 刘文娴, 田承宇, 王雪莲. GFRP锚杆的综合性能与锚固机理研究[J]. 交通科学与工程, 2016, 32(4): 69-74. https://www.cnki.com.cn/Article/CJFDTOTAL-CSJX201604012.htmLiu W X, Tian C Y, Wang X L. Research on comprehensive performance and anchoring mechanism of GFRP bolt[J]. Transportation Science and Engineering, 2016, 32(4): 69-74(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-CSJX201604012.htm [10] Alves J, El-Ragaby A, El-Salakawy E. Durability of GFRP bars' bond to concrete under different loading and environmental conditions[J]. Journal of Composites for Construction, 2010, 15(3): 249-262. [11] 孙奇. GFRP锚杆冻融循环与长期荷载作用力学性能试验研究[D]. 长沙: 中南大学, 2012.Sun Q. Experimental study onmechanical properties of GFRP bolt under freezing-thawing cycle and long-term load[D]. Changsha: Central South University, 2012(in Chinese with English abstract). [12] 李金玉, 彭小平, 邓正刚, 等. 混凝土抗冻性的定量化设计[J]. 混凝土, 2000, 11(9): 61-65. https://www.cnki.com.cn/Article/CJFDTOTAL-HLTF200012015.htmLi J Y, Peng X P, Deng Z G, et al. Quantitative design of frost resistance of concrete[J]. Concrete, 2000, 11(12): 61-65(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-HLTF200012015.htm [13] 胡金星. GFRP锚杆锚固性能研究与分析[D]. 长沙: 中南大学, 2012.Hu J X. Research and analysis of anchorage performance of GFRP bolt[D]. Changsha: Central South University, 2012(in Chinese with English abstract). [14] 程良奎, 范景伦, 韩军, 等. 岩土锚固[M]. 北京: 中国建筑工业出版社, 2003.Cheng L K, Fan J L, Han J, et al. Rock and soil anchorage[M]. Beijing: China Architecture and Building Press, 2003(in Chinese). [15] 潘学军. 抗拔锚杆承载机理的数值模拟及纵向振动分析[D]. 广州: 中山大学, 2010.Pan X J. Numerical simulation and longitudinal vibration analysis of load-bearing mechanism of anti-anchor bolt[D]. Guangzhou: Sun Yat-sen University, 2010(in Chinese with English abstract). [16] 邓芃, 王志刚, 刘艳, 等. 冻融后钢筋与页岩陶粒混凝土黏结性能试验研究[J]. 中国科技论文, 2021-04-21: 1-7.Deng P, Wang Z G, Liu Y, et al. Experimental study on bonding properties of steel bar and shale ceramsite concrete after freeze-thaw[J]. China Science and Technology Paper, 2021-04-21: 1-7(in Chinese with English abstract). [17] 段建, 言志信, 郭锐剑, 等. 土层锚杆拉拔界面松动破坏分析[J]. 岩土工程学报, 2012, 34(5): 936-941. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201205026.htmDuan J, Yan Z X, Guo R J, et al. Failure analysis of soil anchors induced by loose interface under pullout load[J]. Chinese Journal of Geotechnical Engineering, 2012, 34(5): 936-941(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201205026.htm [18] 袁卫军, 高荣雄, 张华伟, 等. 高强螺栓植筋拉拔试验研究[J]. 公路交通科技: 应用技术版, 2016, 12(8): 197-199. https://www.cnki.com.cn/Article/CJFDTOTAL-GLJJ201608077.htmYuan W J, Gao R X, Zhang H W, et al. Study on drawing test of high strength bolt planting bar[J]. Journal of Highway and Transportation Technology : Applied Technology Edition, 2016, 12(8): 197-199(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-GLJJ201608077.htm [19] 蒙胜益, 沈锋, 金双华, 等. GFRP锚杆水泥砂浆尺寸效应黏结性能试验研究[J]. 广东土木与建筑, 2018, 25(9): 62-64. https://www.cnki.com.cn/Article/CJFDTOTAL-GDTM201809020.htmMeng S Y, Shen F, Jin S H, et al. Experimental study on bonding performance of cement mortar with size effect of GFRP bolt[J]. Guangdong Civil & Architecture, 2018, 25(9): 62-64(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-GDTM201809020.htm [20] 李祝龙, 梁乃兴. 掺加丁苯胶乳对水泥砂浆及水泥混凝土刚性与耐磨性的影响[J]. 西安公路交通大学学报, 1996, 16(4): 38-41. https://www.cnki.com.cn/Article/CJFDTOTAL-XAGL604.008.htmLi Z L, Liang N X. Effect of styrene butadiene latex on rigidity and wear resistance of cement mortar and cement concrete[J]. Journal of Xi'an Highway Jiaotong University, 1996, 16(4): 38-41(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-XAGL604.008.htm [21] 张伟丽, 项伟, 贾海梁. 冻融循环对砂浆岩石锚杆锚固力影响的试验研究[J]. 岩石力学与工程学报, 2014, 33(3): 558-566. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201403015.htmZhang W L, Xiang W, Jia H L. Experimental study on the mechanical properties of grouted rock under freeze-thaw condition[J]. Chinese Journal of Rock Mechanics and Engineering, 2014, 33(3): 558-566(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201403015.htm [22] Vlahou I, Worster M G. Ice growth in a spherical cavity of a porous medium[J]. Journal of Glaciology, 2010, 56: 271-277. [23] 张慧梅, 杨更社. 冻融岩石损伤劣化及力学特性试验研究[J]. 煤炭学报, 2013, 38(10): 1756-1762. https://www.cnki.com.cn/Article/CJFDTOTAL-MTXB201310008.htmZhang H M, Yang G S. Experimental stusy on damage degradation and mechanical properties of freezing-thawing rock[J]. Journal of China Coal Society, 2013, 38(10): 1756-1762(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-MTXB201310008.htm -