摘要
以千枚岩这一典型软岩为对象,通过高地温、高渗透水压、高围压条件下的三轴卸荷试验,研究热—水—力(THM)耦合作用下千枚岩的变形破坏特征;以大理—瑞丽铁路高黎贡山隧道为例,采用数值模拟方法模拟THM耦合作用下千枚岩隧道的大变形;结合试验结果和数值模拟结果,探讨THM耦合作用下千枚岩隧道大变形的机理。结果表明:高渗透水压和高地温对千枚岩裂缝的产生和扩张起着促进作用,随着渗透水压、地温的升高,千枚岩的峰值应力降低,并且渗透水压的影响大于地温的影响;在THM耦合作用下,隧道边墙处的位移最大,拱脚处的应力相对集中,洞壁处的渗流速度最大,地温的分布主要受地下水渗流方向控制;隧道洞壁的应力、位移和渗流速度随地温的升高而增大。提出"HM,TH,T→M"的THM耦合模式。得到THM耦合作用下千枚岩隧道产生大变形的机理为:高地温将造成围岩发生初始热损伤;高渗透水压将促进围岩软化并使其内部裂纹进一步扩展;当隧道开挖形成的二次应力超过围岩屈服强度时,将导致围岩塑性流动。
In order to study the deformation and failure characteristics of phyllite under thermo-hydromechanical（THM）coupling,the conventional triaxial unloading tests were carried out for phyllite,the typical soft rock,under the conditions of high ground temperature,high seepage water pressure and high confining pressure.Taking the Gaoligong Mountain tunnel of Dali-Ruili Railway as an example,the numerical simulation of large deformation of phyllite tunnel under THM coupling was performed.According to experimental results and numerical simulation results,the large deformation mechanism of phyllite tunnel under THM coupling was discussed.Results show that high seepage water pressure and high ground temperature promote the growth of phyllite crack.The peak stress of phyllite is reduced by increasing seepage water pressure and ground temperature,and the influence of seepage water pressure is greater than that of ground temperature.Under THM coupling,the displacement of tunnel side wall is the greatest,the stress of arch springing is relatively concentrated,the seepage velocity of tunnel wall is the greatest,and the distribution of ground temperature is mainly controlled by the direction of groundwater seepage.The stress,displacement and seepage velocity of tunnel wall increase with the increase of ground temperature.On the basis of above analysis,the＂HM,TH,T→M＂coupling mode is established.The large deformation mechanisms of phyllite tunnel under THM coupling are as follows：high ground temperature will give rise to the initial thermal damage of surrounding rock;high seepage water pressure will promote surrounding rock softening and the further growth of its internal crack;when the secondary stress due to tunnel excavation exceeds the yield strength of surrounding rock,then the plastic flow surrounding rock is formed.
出处
《中国铁道科学》
EI
CAS
CSCD
北大核心
2016年第5期66-73,共8页
China Railway Science
基金
国家自然科学基金资助项目(41230635
41102189)
四川省教育厅项目(16ZA0095)
地质灾害防治与地质环境保护国家重点实验室课题(SKLGP2013Z004)
关键词
隧道变形
变形机理
热—水—力耦合作用
千枚岩隧道
渗透水压
地温软岩
Tunnel deformation
Deformation mechanism
Thermo-hydro-mechanical coupling
Phyllite tunnel
Seepage water pressure
Geothermal soft rock
