环锚衬砌的预应力荷载传递机理及其应力状态解析
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1.Influencing factors of lining crack width in hydraulic tunnels under high internal water pressure
- 关键词:
- Safety factor;Reinforced concrete;Circumferential reinforcement;Numerical calculation;Pumped storage power station;Random distribution;Randomly distributed;Reinforced concrete lining;Reinforcement ratios;Reinforcement spacing
- Cao, Ruilang;Wang, Yujie;Zheng, Lifeng;Zhao, Yufei
- 《China Rock 2020 Conference》
- 2020年
- October 23, 2020 - October 26, 2020
- Beijing, China
- 会议
The crack width of reinforced concrete lining under complex working conditions is a key factor affecting the safety of high-pressure hydraulic tunnels. This research investigates the lining of a pumped storage power station under high internal water pressure of 8.0 MPa. Considering the constraint of reinforcement and the combined bearing of rock mass and lining, the effect of circumferential reinforcement ratio, reinforcement location, tunnel radius, and surrounding rock on crack width is analyzed. On this basis, the relationship between the random distribution of lining parameters and crack width is obtained by numerical calculation. The results show the importance of adjusting the reinforcement spacing and reinforcement ratio to achieve the optimal constraint on the lining crack width. When the parameters are randomly distributed, the cracks appear locally mutated, but still form a strip distribution, with no obvious change in the average crack width.
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© Published under licence by IOP Publishing Ltd.2.The Influence of the Variable Thickness of Prestressed Linings with Annular Anchors on its Mechanical Properties
- 关键词:
- Anchors;Numerical methods;3-D numerical modeling;Diversion project;Hydraulic tunnels;Large diameter;Load-bearing capacity;Pressure tunnel;Variable thickness;Water pressures
- Wang, Yujie;Cao, Ruilang;Shen, Qiang;Zhao, Yufei;Qi, Wenbiao
- 《China Rock 2020 Conference》
- 2020年
- October 23, 2020 - October 26, 2020
- Beijing, China
- 会议
By embedding annular anchors, prestressed linings with annular anchors provide active prestress, which can effectively resist the high internal water pressure in large-diameter hydraulic tunnels. The variable thickness of concrete liners along the circumference can significantly influence the mechanical properties of the lining. On the basis of the prestressed lining of a 6.8-m-diameter pressure tunnel in the Yinsong Diversion Project, we adopted a 3D numerical modeling method to study the influence of the average and local thicknesses of the lining on its mechanical properties. The results show that the prestress of the lining used in resisting the internal water pressure is ultimately derived from tensioning the annular anchors. The average thickness of the lining has little effect on its load-bearing capacity. In elliptical lining, an annulus of a slight tensile stress area appeared on the inner side of the lining, whereas the crown and invert sections will form the weak area because of structural bending moments.
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© Published under licence by IOP Publishing Ltd.
