PDF全文阅读

海维深¹  ,  李正虎²  ,  和振海^3 ,4  ,  刘    云²  ,  杨新志²  ,  梁    滔²  ,  郝倩倩²

 

(1 .  云南省公路科学技术研究院，云南 昆明 650000  ;  2.  云南勐绿高速公路投资开发有限公司，云南 普洱 665000; 3 .  中铁开发投资集团有限公司 ，云南 昆明 650000 ;  4.  中铁开投勐绿高速工程指挥部 ，云南 普洱 665000)

摘   要 ：针对隧道喷射混凝土回弹率较高的问题，选用一种微纳米粉体降弹剂改良喷射混凝土的性能。对降弹剂掺加 3% 、6% 、9% 、12% 和 15% 的胶砂流动度和抗折、抗压强度进行试验；开展单掺粉煤灰 、复掺粉煤灰与降弹剂不同配合比 C25 湿喷混凝土的回弹率研究。结果表明： 随降弹剂掺量增加，胶砂流动度减小，胶砂 1   和 3 d 的抗折 、抗压强度逐渐降低 ，28 d 的抗折、抗压强度均先增大后降低，掺量为 6% 时强度最大，28 d 抗折、 抗压强度比分别为 1 . 049 和 1 . 014 ;  复掺粉煤灰与降弹剂湿喷混凝土的回弹率显著低于粉煤灰湿喷混凝土的回弹率，胶凝材料总量为 430 kg/m3 、复掺 14% 粉煤灰与 6% 降弹剂的综合回弹率最低，为 8. 09% 。掺加6% 降弹剂能够促进喷射混凝土抗压强度增长，减小胶凝材料用量。研究成果可供类似工程参考和借鉴。

关键词： 隧道工程 ；喷射混凝土 ；回弹率 ；配合比 ；降弹剂

中图分类号：TU528 . 041            

文献标志码：A            

文章编号： 1005- 8249  (2024)  06- 0019- 06

DOI:10. 19860/j.cnki.issn1005 - 8249.2024.06.004

 

HAI Weishen¹  ,  LI Zhenghu² ,  HE Zhenhai³ , ⁴ ,  LIU Yun² ,  YANG Xinzhi² ,  LIANG Tao² ,  HAO Qianqian²

(1 . Yunnan Science & Technology Research Institute of Highway ,  Kunming 650000 ,  China; 2. Yunnan Menglv Expressway Investment Development Co. ，Ltd. ，Pu ’er 665000 ,  China; 3 . China Railway Development & Investment Group Co. ，Ltd. ，Kunming 650000 ,  China;

4. Menglv Expressway Engineering Headquarters of China Railway

Development & Investment Group Co. ，Ltd. ，Pu ’er 665000 ,  China)

Abstract: In response to the challenge of high rebound rates in tunnel shotcrete applications, a micro-nano powder additive has been selected to enhance the performance of shotcrete. The fluidity, flexural and compressive strength of mortar samples containing 0%, 3%, 6%, 9%, 12%, and 15% of the additive by mass were tested. Additionally, an investigation into the rebound rate of C25 wet-mixed shotcrete was conducted, comparing formulations with single additions of fly ash and composite mixtures incorporating both fly ash and the additive at various proportions. The results showed that the fluidity of mortars decreases with the increase of the dosage of additive, the flexural and compressive strengths in 1d and 3d decrease gradually, and the flexural and compressive strengths of mortars in 28d increase first and then decrease. The flexural and compressive strengths of mortar specimens in 28d is the highest when adding 6% micro-nano additive , and the flexural and compressive strength ratio in 28d are 1.049 and 1.014. The rebound rate of wet sprayed concrete mixed with fly ash and additive is significantly lower than that of wet sprayed concrete with fly ash, the total amount of cementitious material is 430kg/m³, and the comprehensive rebound rate is the lowest when mixed with 14% fly ash and 6% additive, which is 8.09%. Adding 6% additive can promote the increase of compressive strength of shotcrete and reduce the amount of cementitious material. The research results can provide reference and inspiration for similar engineering projects.

Keywords: tunneling；wet-mix shotcrete；shotcrete-rebound；mix proportion；tackifier

*基金项目：云南省交通运输厅科技创新及示范项目  (2021- 102) ;  中铁开发投资集团有限公司科技研究开发计划项目  (2022- B 类- 05) 。

作者简介：海维深  (1993—) ,  男，硕士，工程师，研究方向： 喷射混凝土和岩土工程。

收稿日期：2024- 01 - 28