【摘要】 岩溶渗流效应包括渗流场的力学效应和岩体软化效应。针对富水岩溶区地下工程的特殊赋存环境,提出了岩溶地下厂房3维渗流场力学效应耦合计算方法和基于强度折减原理的渗流软化效应分析方法。计算分析了不同工况、围岩不同软化程度下洞周变形破坏规律。提出地下洞群整体软化安全系数的确定方法,定量评价不同工况下地下厂房洞群围岩整体相对稳定状态,分析岩溶渗流软化效应对围岩稳定的影响。工程实例表明:考虑渗流场力学效应时,开挖完毕围岩变形都明显增大,变化规律与监测相符;对比无渗流场、考虑施工期渗流场和考虑运行期渗流场各工况的整体软化安全系数变化规律发现,渗流场软化效应显著;运行期正常蓄水后,地下水位的提高引致厂区渗流场调整,对围岩整体稳定存在明显影响。整体软化安全系数能够有效地反映渗流软化效应对岩溶地下厂房围岩稳定的影响,为岩溶区地下厂房工程优化设计、施工监测及安全运行评价提供有益参考。更多还原

【Abstract】 Mechanical effect and softening effect are two typical effects on underground structures subjected to seepage flow at Karst region.For underground engineering at Karst region with rich groundwater,a finite element method coupling mechanical effect of seepage to simulate excavation and support construction was proposed.And a strength reduction methodology for softening effect analysis of seepage was also put forward based on the identification of the general softening safety factor of underground caverns.The distribution of deformation and damage around openings was calculated and analyzed subjected to different seepage conditions and different softening degrees of rockmass strength.The softening safety factors were identified to quantificationally assess the stability of the caverns related to different calculation conditions and to analyze the impact of softening effect of seepage on the stability of the surrounding rock.The calculation results illustrated with a practical excavation project at Karst region showed that the displacements around the openings evidently increase when the mechanical effect of seepage is coupled to excavation simulation.It was indicated that the softening effect is of significance on the surrounding rock by comparison of softening safety factors under different seepage conditions.For the underground caverns,the growing of groundwater level would lead to unsteady seepage flow,which has significant impact on the stability of the rockmass.The softening safety factor is able to characterize the effect of seepage on the surrounding rock stability of underground caverns that would be helpful to well design,construction monitoring and safety assessment of underground engineering at Karst region.更多还原