考虑拉压模量及主应力顺序的隧洞应力解析解

Analytical Solutions of Hydraulic Tunnel With a Consideration of Variation of Principal Stresses Orders and Different Elastic Moduli in Tension and Compression

针对圆形水工隧洞,采用统一强度理论和弹脆塑性模型,考虑了不同工况下主应力顺序变化、不同拉压模量、中主应力以及软化等因素的综合影响,推导了圆形水工隧洞问题的弹塑性解答,探讨了不同拉压模量比、中主应力等对隧洞临界压力以及极限压力的影响.算例分析结果表明,对于圆形水工隧洞应正确考虑不同工况下第一主应力的变化,且应重视拉压模量差异的影响,传统的压力隧洞弹塑性解答假定岩土体具有相同的拉压模量,使得工程设计偏于保守,考虑拉压模量的不等可以更真实的反映岩土材料的力学特性,以期达到设计经济和安全.该结果为水工压力隧洞的弹塑性分析提供了理论依据,对工程设计具有一定参考价值.

Based on the unified strength theory and elastic-brittle-plastic model,analytical solutions of elastic-plastic for circular hydraulic tunnel are introduced considering the principal stresses orders under different engineering conditions,different elastic moduli in tension and compression,the intermediate principal stress and softening.The influences of different tension and compression modulus ratios and the intermediate principal stresses on the critical pressure and ultimate pressure for hydraulic tunnels are discussed.The example analysis results show that the first principal stress should be reasonably considered,if different elastic moduli in tension and compression are neglected,large errors may be resulted in.Traditional elastic-plastic solutions of hydraulic tunnel based on an assumption that the geotechnical materials have the same elastic moduli in tension and compression may bring out a more conservative engineering design.A consideration of different elastic moduli in tension and compression reflect the true mechanical property of geotechnical materials,therefore,an economic and safety design is obtained.This result provides some reference value for engineering design and a theory basis for the elastoplastic analysis circular hydraulic tunnels.