裂损衬砌网-锚与板-锚加固结构力学特性试验

为探明裂损衬砌维修加固后的力学性能，对裂损衬砌新型网-锚、板-锚轻型快速微创组合加固结构的全过程力学特性进行了研究。通过自主研制的卧式偏心加载装置，对网-锚、板-锚加固裂损衬砌后形成的组合结构进行大偏心受压反复加卸载试验，揭示了钢筋混凝土和素混凝土裂损衬砌加固组合结构的全过程荷载-挠度关系、破坏模式、裂缝发展规律及网/板片应变演化过程。研究结果表明：对于钢筋混凝土衬砌，未加固、网-锚加固和板-锚加固结构5次反复加卸载后峰值承载力相比首次峰值承载力分别降低了28.9%、25%和16.7%，网-锚加固和板-锚加固后结构的主裂缝总开展量相比未加固时分别减小了74.3%和61.4%,总挠度分别增加了25.5%和25.54%，裂损衬砌结构的裂缝宽度发展得以有效抑制,峰后韧性显著提高,剩余承载能力得到了更充分的发挥；对于素混凝土衬砌，网-锚加固和板-锚加固后最大峰后荷载相比首次峰值点分别增加了30.8%和6.7%,峰后总位移比峰前分别增加了1 040.6%和413.0%，受拉侧主裂缝总开展相比开裂时的裂缝宽度分别增加约11.78倍和11.81倍，素混凝土衬砌由开裂后“一裂即坏”的脆性破坏转化为延性破坏，峰后韧性大幅增加；网-锚加固后结构掉渣风险显著降低且无掉块现象出现，板-锚加固后无掉渣、掉块现象；短锚无拔出迹象，仅个别短锚出现轻微弯曲变形；板-锚组合加固结构的峰后韧性要优于网-锚组合加固结构。

Experimental Investigation on the Mechanical Performance of Retrofitted Cracked Linings with Mesh-bolts and Plate-bolts

The mechanical characteristics of a cracked lining retrofitted with mesh-bolts and plate-bolts were investigated to reveal the mechanical performance of cracked linings after reinforcement. Through a horizontal eccentric loading setup, a large-bias pressure repeated loading test was conducted on the retrofitted cracked lining. The load-deflection relationship, failure mode, crack development law, strain evolution process of the reinforcement, and plain cracked lining retrofitted with a mesh grid/corrugated steel plate were examined. The results showed that the first peak load capacity of the reinforced concrete structure compared to that of the unreinforced, mesh-bolts reinforcement, and plate-bolts reinforcement decreased by 28.9%, 25.5%, and 16.7%, respectively. In addition, the crack width decreased by 74.3% and 61.4% and deflection increased by 25.5% and 25.54% after the mesh-bolts and plate-bolts reinforcements, respectively. The width of the cracked lining was effectively restrained. The post-peak resilience of the reinforced concrete was improved, and the residual bearing capacity of the structure could be completely utilized. Compared to the first peak point, the maximum post-peak load of the plain concrete structure with mesh-bolts- and plate-bolts reinforcements increased by 30.8% and 6.7%, respectively. Compared to the pre-peak displacement, the total post-peak displacement increased by 1 040.6% and 413.0%, respectively. Additionally, the main crack width of the lining at the tensile side after retrofitting increased by approximately 11.78 and 11.81 times, respectively. The plain concrete lining changed from brittle to ductile failure. The post-peak resilience of the plain concrete lining was improved significantly. The risk of slag falling was significantly reduced, no blocks fell after the mesh-bolts reinforcement, and no slag or blocks fell after the plate-bolts reinforcement. Short bolts were not pulled out during the tests, and a few short bolts were slightly bent. The post-peak resilience of the cracked lining with the plate-bolts reinforcement was higher than that of the mesh-bolt reinforcement.