高压水工隧洞透水衬砌设计方法与理论研究

Research of pervious lining design and theory for high pressure hydraulic tunnel

基于高压隧洞透水衬砌理论,考虑了钢筋应变不均匀系数ψ_1和裂缝间混凝土应变不均匀系数ψ_2对配筋计算的影响,讨论了透水衬砌的设计方法,给出了使用透水衬砌理论进行工程设计的基本步骤,最后结合工程实例量化分析了考虑应变不均匀系数ψ_1、ψ_2影响的钢筋应力与渗流量变化特征.计算结果表明,ψ_1、ψ_2对钢筋应力和单位管长渗流量均有明显影响,且前者的影响大于后者,同等配筋条件下的钢筋应力差别主要来源于ψ_1,但当配筋率减小到一定程度时(小于0.4%),ψ_1、ψ_2对渗流量的影响可以忽略;同时,随着钢筋应力的逐渐增加,ψ_1、ψ_2的影响逐渐减小,且在钢筋应力达到某一较大数值后(如ψ_1=1.0时,120MPa),由于钢筋的作用得以充分发挥,ψ_2的影响基本可以忽略.

Based on the pervious lining theory for high pressure tunnel, the influences of the reinforcing steel bar strain nonuniformity coefficient ψ1 and the strain nonuniformity coefficient of concrete between cracks ψ2 on the reinforcement computation are taken into account in the design of pervious lining. In addi-tion, the basic design steps based on the pervious lining theory are presented. P mally, considering me strain nonuniformity coefficient ψ1 ψ2, the change characteristics of reinforcing steel stresses and seepage flow are analyzed with an actual case study. The results show that the ψ1 and ψ2 have obvious effects on re- inforcing steel stresses and seepage flow; and the influence of the former is greater. Moreover, the differ- ences of reinforcing steel stresses under the same reinforcement mainly result from ψ1. As the reinforce- ment ratio decreases to some degree （less than 0.4%）, the influences of both ψ1 and ψ2 on seepage flow can be neglected. Meanwhile, the effects of ψ1 and ψ2 decrease with the increasing of the reinforcing steel stres- ses; and when the stress level of reinforcing steel is beyond a certain value （such as ψ1= 1.0, 120 MPa）, the influence of ψ2 could be neglected since the steel bar can play the role adequately.