土工基础

›› 2019, Vol. 33 ›› Issue (2): 181-186.

• 工程实录 • 上一篇    下一篇

高地应力软岩隧道有限元仿真与工程应用

龚卫锋1，王东英2,3   

  1. （1.中国建筑五局投资管理公司，长沙 410000；2.中国科学院武汉岩土力学研究所岩土力学与
    工程国家重点实验室，武汉 430071；3.中国科学院大学，北京 100000 ）
  • 收稿日期:2018-07-06 修回日期:2018-07-27 出版日期:2019-04-20 发布日期:2019-04-22
  • 作者简介:龚卫锋（1978-），男，工程师，研究方向为土木工程。
  • 基金资助:

    云南省交通科技项目［云交科教(2016)140(A)，云交科教（2017）23号］；国家自然科学基金(51274189)

Finite Element Simulation of Tunnel Excavation in Soft Rock Mass with High Geo-Stress

GONG Weifeng1, WANG Dongying2,3   

  1. （1.The Investment Management Company of China Construction Fifth Engineering Division Co. Ltd., Changsha 410000；
    2.State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071；
    3.University of Chinese Academy of Sciences, Beijing 100000）
  • Received:2018-07-06 Revised:2018-07-27 Online:2019-04-20 Published:2019-04-22

摘要： 高地应力软岩隧道开挖过程中围岩自稳能力差，极易出现坍塌、冒顶等大变形灾害，选择合适的施工工法至关重要。以某高地应力软岩隧道为对象，基于有限元仿真模型，结合现场监测结果，分析了采用上下台阶分步法施工时高地应力软岩隧道围岩及支护结构的力学行为。分析表明：①上下台阶分步法施工适合于高地应力软岩隧道开挖，具有围岩变形小、安全可靠的优点；②开挖时，围岩塑性区由边墙两侧拱腰向拱部和仰拱位置逐渐扩展；③由于洞顶、拱底均向洞内收敛，致使两侧腰处承受较大压力而向外扩张。两侧腰处围岩竖向应力较大，而洞顶和拱底附近则水平向应力集中。同样的，支护结构在两侧腰处承受较大拉应力，而在洞顶、拱底位置承受较大压应力。

关键词: 高地应力, 软岩隧道, 上下台阶分步法, 有限元

Abstract: The stability of the excavated tunnels in the high geostress soft rock mass is usually poor. Geohazards with large tunnel deformations, such as, collapse and roof squeeze, are frequently encountered in the tunnel excavation projects in these problematic rock mass. It is critically important to select an appropriate construction method. This paper presents the analytical results of a tunnel excavation support in the high geostress soft rock mass, and the analytical model was calibrated with the observed construction results. The following conclusions can be made: 1) Stepped excavation method is an appropriate construction method for the tunnel excavation in the soft rock mass with high geostresses. It has the advantage of small tunnel deflection and is reliable in the construction safety; 2) The plastic zones within the soft rock mass are initiated at the middle portion of the side walls and develop upward to the crown of the tunnel; 3) The deformations at the bottom and crown of the tunnel are toward the excavated area, whereas, larger stresses could be found a the middle portion of the tunnel walls and the deformation of these areas are toward the rock mass. Larger vertical stresses are also encountered at the middle portion of the side walls and horizontal stress concentrations are encountered at the bottom and the crown of the excavated tunnel. The supporting structures have large tensile stress at the middle portion of the side walls and larger compressive stresses could be found at the crown and bottom areas that supporting the tunnel.

Key words: high geo-stress areas, tunnel in soft rock mass, stepped excavation, finite element analysis