External water pressure on diversion tunnel lining in complex karst area
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摘要: 衬砌外水压力的合理计算是岩溶地区引水隧洞设计关注的重点,对结构设计参数选取及运行安全影响重大。针对滇中引水工程大理Ⅱ段引水隧洞,采用ABAQUS数值模拟的方法对不同衬砌及注浆圈参数下隧洞衬砌外水压力及渗流场变化规律进行研究分析,以确定合适的设计参数。研究结果表明:衬砌全封堵时外水压力基本可认为等效于该点处的静水压力,一般不能考虑水头折减;增大衬砌渗透系数是降低衬砌外水压力极为有效的措施,但同时对渗流场产生较大影响;减小注浆圈渗透系数或增大其厚度在降低衬砌外水压力的同时可有效减小渗流场扰动,极大缓解排水减压和环境保护之间的矛盾。通过分析不同因素对衬砌外水压力的影响,所得结果可为复杂岩溶地区隧洞工程防排水系统设计提供参考。Abstract: The reasonable calculation of the external water pressure on the tunnel lining is the focus of the design of the diversion tunnel in the karst area, which has a great influence on the selection of structural design parameters and the operation safety of the hydropower station. In view of the Dali section Ⅱ diversion tunnel of the water diversion project for the central area of Yunnan Province, the ABAQUS numerical simulation method is applied to studying the variation law of the external water pressure and seepage field of the tunnel lining under the conditions of different lining parameters and grouting circle parameters so as to determine the appropriate design parameters. The analysis results indicate that the external water pressure is basically considered to be equivalent to the hydrostatic pressure at this point when the tunnel lining is fully blocked, and the water pressure reduction cannot be considered in this study. The external water pressure on the tunnel lining can be extremely reduced by increasing the lining permeability coefficient, but it has a great influence on the seepage field. Reducing the permeability coefficient or increasing the thickness of the grouting circle can not only reduce the external water pressure on the lining but also weaken the disturbance to the seepage field, which can greatly alleviate the contradiction between drainage decompression and environmental protection. The research results can provide some references for the design of the waterproof and drainage system in the tunnel engineering in the complex karst area in the southwest China.
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Key words:
- hydroproject /
- diversion tunnel /
- external water pressure /
- seepage field /
- karst area /
- grouting circle parameters
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表 1 材料力学参数统计
Table 1. Material mechanics parameters
材料 密度/
(g·cm-3)弹性模量/
GPa泊松比 黏聚力/
MPa内摩擦角/
°围岩 2.80 24 0.26 1.05 40 注浆圈 2.82 26 0.24 1.10 43 衬砌 2.50 28 0.17 — — -
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