钢-玄武岩混杂纤维混凝土二次衬砌承载能力模型试验研究

Model test of bearing capacity of steel-basalt hybrid fiber reinforced concrete secondary lining

为进一步在地下工程中推广应用玄武岩纤维,通过素混凝土、钢纤维混凝土(SFRC)及钢-玄武岩混杂纤维混凝土(SBFRC)的室内立方体抗压强度、弯曲韧性试验以及二次衬砌承载力学行为模型试验,对SBFRC二次衬砌的承载能力进行研究。试验研究结果表明:同体积纤维掺量条件下,SBFRC立方体抗压强度和弯曲韧性均较SFRC的略低,SFRC和SBFRC的韧度均为优秀等级,掺入纤维后试件由脆性破坏变为塑性破坏;SFRC二次衬砌和SBFRC二次衬砌初裂荷载比素混凝土二次衬砌提高20%,破坏荷载提高100%;掺入纤维后混凝土二次衬砌的承载能力得到极大提高,SBFRC二次衬砌的承载能力比SFRC二次衬砌的略差,在对承载能力提高的贡献中,纤维的增韧效果较好。

In order to promote the application of basalt fiber in underground engineering, based on the test results of the cubic compressive strength, bending toughness of the plain concrete, steel fiber reinforced concrete(SFRC)and steel-basalt hybrid fiber reinforced concrete(SBFRC) and the test of the mechanical behavior of the secondary lining, the bearing capacity of SBFRC secondary lining was studied. The results show that the cubic compressive strength and bending toughness of SBFRC are slightly lower than that of SFRC under the same volumetric fiber content;the toughness of SFRC and SBFRC is excellent and the specimen changes from brittle failure to plastic failure after adding fiber. In addition, the initial cracking load of SFRC and SBFRC secondary lining is improved by 20% compared with plain concrete secondary lining and damage load is increased by 100%. The bearing capacity of the secondary lining of concrete is greatly improved after adding fiber, while the bearing capacity of SBFRC secondary lining is slightly lower than that of SFRC secondary lining. In the contribution to the improvement of bearing capacity, the toughening effect of fiber is better.