Journal of Yangtze River Scientific Research Institute ›› 2023, Vol. 40 ›› Issue (3): 151-157.DOI: 10.11988/ckyyb.20210975

• HYDRAULIC STRUCTURE AND MATERIAL • Previous Articles     Next Articles

Parameter Sensitivity Analysis for Bearing Ratio of Internal Water Pressure in Hydraulic Pressure Tunnel Strengthened with CFRP

QIN Gan1,2, CHEN Rui1, JIN Dian-qi2, CAO Sheng-rong3, YANG Fan3   

  1. 1. School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen518055, China;
    2. Shenzhen Urban Public Safety and Technology Institute, Shenzhen 518000, China;
    3. School of Water Resources and Hydropower Engineering, Wuhan University, Wuhan 430072, China
  • Received:2021-09-14 Revised:2021-11-15 Online:2023-03-01 Published:2023-03-28

Abstract: Carbon Fibre Reinforced Polymer (CFRP) bears not only the varying external soil and water loads, but also part of the internal water pressure when used in strengthening pressure tunnels. To investigate the joint bearing mechanism of the composite structure containing CFRP, adhesive lining, and concrete under internal water pressure, we established a “solid-spring-solid” 3D finite element model of pressurized water conveyance tunnel strengthened with CFRP, and verified the validity of the model via model test. By using this model, we examined the ratio of bearing internal water pressure between lining concrete and CFRP under varying conditions including elastic modulus of adhesive layer (Ea), thickness of adhesive layer (ta), elastic modulus of CFRP (Ec), and thickness of CFRP (tc). Results reveal that tc and Ec are dominant factors that affect the bearing ratio. In the presence of 1-3 layers of CFRP, with tc gradually increasing from 0.1 mm to 2 mm, the percentage of internal water pressure borne by lining concrete declined by 34.25%, 47.776%, and 53.931%, respectively; when Ec grew from 100 GPa to 600 GPa, that percentage dropped by 6.482%,11.945%,and 16.509%,respectively. Range analysis also manifest that the percentage of internal water pressure borne by lining concrete is most sensitive to tc,followed by Ec,Ea,and ta in descending order. In conclusion, improving the thickness and modulus of CFRP is the key to enhancing the utilization of CFRP and to reducing the percentage of internal water pressure borne by lining concrete.

Key words: pressure tunnel, tunnel strengthened with CFRP, composite structure, bearing ratio of internal water pressure, parameter analysis

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