香钦多隧道地应力分析及软岩变形应对措施

Analysis on Ground Stress for Xiangqinduo Tunnel and Measures to Cope with Soft Rock Deformation

根据香钦多隧道地应力测试结果,结合隧址区岩石物理力学特征,对隧道工程围岩稳定性进行了分析。分析结果表明：该工程区构造应力仍占主导地位,地应力以NEE向水平挤压为主,洞身部位的最大水平主应力为10.55～14.70 MPa,最小水平主应力为6.22～8.93 MPa,垂直主应力为4.96～5.91 MPa;由于隧道轴向与最大主应力方向局部夹角较大、地应力较高,隧道局部发生软岩变形的可能性大。建议隧道开挖采用似椭圆形断面,且长轴为水平方向,短轴为竖直方向。

Based on ground stress measurement results of Xiangqinduo tunnel, and the mechanical performance of tunnel rocks, the paper analyzed the stability of surrounding rocks. The results indicate that structural stress still prevail, ground stress mainly takes the form of horizontal squeeze at NEE direction. For the tunnel body, the main ground stress maximum is 10.55 ～ 14.70 MPa and minimum is 6.22 ～ 8.93 MPa at horizontal direction, while varies between 4.96 - 5.91 MPa at vertical direction. Due to the relatively high ground stress and the large angle between the tunnel axle and the main stress, there is a great chance for the occurrence of soft rock local deformation. The paper suggests a like-oval cross section for excavation where the long axle represents the horizontal direction, and the short axle represents the vertical one.