【摘要】 针对深埋圆形隧洞爆破开挖,采用双向受压条件下的压剪裂纹扩展模型和应力强度因子计算公式,分析开挖面上岩体应力瞬态释放和邻近的围岩应力瞬态调整对围岩开裂过程的影响。结果表明,与准静态卸载条件相比,开挖面上岩体应力瞬态释放在围岩中产生附加动应力,导致围岩径向卸载和环向加载效应放大,加剧了深埋洞室围岩开裂效应,导致开裂范围增大;开挖卸载速率越快,围岩中产生的附加动应力幅值越大,围岩的开裂效应越显著。更多还原

【Abstract】 For a case of circular deep tunnel,the effect of abrupt in-situ stress release in terms of cracking in surrounding rocks is investigated by adopting an initiation model of cracks under biaxial compressions.In addition,a formula of the stress intensity factor is employed.The results show that,compared to a quasi-static process of stress release,the transient release of in-situ stress on excavation face generates an additional dynamic stress in surrounding rocks.In this circumstance,the radial unloading and the circumferential loading are enlarged by this additional stress,thus cracking in surrounding rocks is aggravated during this transient process.The shorter the release duration of stress is,the greater the amplitude of the additional stress and the cracking extent become.更多还原