高压水工隧洞钢筋混凝土衬砌裂缝开度计算方法评析

针对在复杂工作条件下的高压水工隧洞衬砌裂缝宽度的计算问题,基于国内外现有主要裂缝计算方法理论基础,通过研究内水压力、隧洞半径、衬砌厚度、保护层厚度、围岩抗力、混凝土抗拉强度以及衬砌配筋率等参数对衬砌裂缝开裂特性和扩展规律的影响,结合某抽水蓄能电站高压水工隧洞工程案例,开展各裂缝计算方法的综合评析。结果表明:(1)对高压水工隧洞衬砌而言,衬砌裂缝宽度主要受内水压力、围岩抗力和钢筋应力参数的影响,其中内水压力的影响最为显著;(2)由于裂缝开展规律不同,基于一般混凝土构件建立的裂缝计算方法不适用于高压水工隧洞,并且计算结果明显与实际情况差别较大;(3)弹性地基梁方法对高压水工隧洞衬砌裂缝宽度计算较为合适。

Analysis on crack-opening calculation method for reinforced concrete lining of high pressure hydraulic tunnel

Aiming at the calculation of the lining crack-width of the high pressure hydraulic tunnel under complicated operation condition，a comprehensive evaluation on all kinds of the crack calculation methods is carried out in combination with an actual case of the high pressure hydraulic tunnel of a pumped storage hydropower station through the study made on the internal water pressure，radius of tunnel，thickness of tunnel，thickness of protection layer，resistance of surrounding rock，concrete tensile strength as well as the influences from the parameters of reinforcement ratio，etc. on the cracking characteristics and the lining cracking expansion law in accordance with the theoretical basis of the main crack calculation methods. The study result shows that ( 1) for the lining of high pressure hydraulic tunnel，the lining crack-width is mainly influenced by internal water pressure，resistance of surrounding rock and stress parameters of reinforcement，in which the influence from internal water pressure is most significant; ( 2) due the difference among cracking development laws，the crack calculation methods established based on the conventional concrete component is not suitable for high pressure hydraulic tunnel and the calculated result is obviously different with that of the actual situation; ( 3) the elastic foundation beam method is more adaptable for the calculation on crack-width of high pressure hydraulic tunnel lining.