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| Experiment on the difference of load bearing of GFRP and steel bars in soft-rock slopes of water diversion from Yangtze to Huai |
| LI Guowei1，2，YU Wei1，3，LI Feng4，WU Jiantao2，CAO Xueshan2，YUAN Junping3，WANG Jingqiu1，3 |
(1. Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering，Hohai University，Nanjing，Jiangsu 210098，China；2. Highway and Railway Research Institute，Hohai University，Nanjing，Jiangsu 210098，China；3. Geotechnical Research Institute，Hohai University，Nanjing，Jiangsu 210098，China；4. Anhui Investment Group Holding Co.，Ltd.，Heifei，Anhui 230000，China)
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Abstract A soft rock slope in the testing project of water diversion canal from Yangtze to Huai is reinforced with the reinforcement bars. The pullout experiment and stress relaxation test on glass fiber reinforced polymer(GFRP) bars and steel bars were carried out in the field in order to investigate the difference of anchoring performance between the GFRP bars and steel bars. The test results show that the ultimate bearing capacity of the GFRP bar is higher than that of the steel bar in soft rock slope. The GFRP bar has higher bond strength at interface than the steel bar. The GFRP bar deformed by breaking off above the grouted zone，whereas the steel bar was pulled out of the rock under the pulling force. The effective anchorage depth of the GFRP bar is shorter than that of the steel bar，and the axial force in GFRP bar degrades faster along the depth compared to that of steel bar. Compared to the steel bar，there is better deformation coordination between the GFRP bar and the grout，i.e.，the grout deformed together with the GFRP bar. The pre-stress attenuation rate of the GFRP bars is less than that of the steel bars. The pre-stress attenuation of the bars is due to the degradation of interface bond. The disturbance of the surrounding rock has also a direct effect on the pre-stress loss. The anchorage performance of the GFRP bar is better than that of steel bar，and its shear stress level is higher than that of steel bar when the interface bond degrades.
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2018, Vol. 37 
