粉砂质板岩隧洞围岩变形破坏特征及稳定性研究

Deformation Failure Characteristics and Stability of Surrounding Rock of Silty-slate Tunnel

以东南亚某在建水电站引水隧洞粉砂质板岩段洞室开挖工程为依托,在现场地质调查测绘的基础上,对粉砂质板岩段围岩变形破坏特征进行分析,结果表明:粉砂质板岩段围岩的变形破坏主要分两种,一种由Ⅳ级结构面相互切割引起的局部垮塌掉块;另一种由断层引起的大规模垮塌变形。并基于有限元软件模拟断层分布发育特征对洞室稳定性的影响,结果表明:断层倾角在30°~60°对洞室稳定性影响较大,当断层位于隧洞中心上部时,对围岩变形的影响最大,特别左侧腰线部位岩体;当其位于隧洞中心下方,影响次之;与隧道中心相交时,影响最弱。研究成果可为后续类似洞段开挖支护方案提供参考借鉴。

Based on the excavation project of the silty SLATE section of the diversion tunnel of a hydropower station under construction in Southeast Asia,the deformation and failure characteristics of surrounding rocks in silty slab rock section are analyzed based on field geological survey and mapping.The results show that the silty plate caves section of surrounding rock deformation and failure mainly divided into two kinds,a kind of local collapse caused by structural planeⅣlevel,falling another large-scale collapse caused by fault.And based on the results of a finite element software,the influence of fault distribution and development characteristics on the stability of the cavity was analyzed.The results are as follows.The fault dip Angle between 30°~60°has a great influence on the stability of the cavity,when the fault is located in the upper center of the tunnel,it has the greatest influence on the deformation of surrounding rock,especially the rock at the left lumbar line.When it is under the center of the tunnel,the effect is second.The impact is weakest when it intersects the center of the tunnel.The research results can provide reference for similar excavation and support schemes.