隧道异形初期支护结构自动化建模及安全评价

Automatic Modeling and Safety Assessment of Tunnel Special-Shaped Initial Support Structure

通过ANSYS对隧道异形支护结构进行数值模拟,结论如下:①研发了一种基于激光点云的隧道异形初期支护结构自动化建模方法,该法可实现包含超欠挖信息的初期支护结构精准化建模;②边墙超挖,结构安全系数增大;拱顶超挖,结构安全系数减小,因此判定"厚边墙、薄拱顶"将是支护结构的最优断面;③通过该建模分析方法,针对隧道每一开挖断面,都可以确定一个允许变形量和安全系数,为逐段或逐榀分析评价初期支护结构、开展施工安全管控奠定基础。

In this paper,numerical simulation of tunnel special-shaped support structure is carried out by ANSYS,and the conclusions are as follows:(1)An automatic modeling method of tunnel special-shaped initial support structure based on laser point cloud is developed,which can realize accurate modeling of initial support structure containing information of over-excavation and under-excavation;(2)Over-excavation of side wall leads to increase of structural safety factor.Because the arch roof is over-excavated and the safety factor of the structure decreases,it is determined that"thick side wall and thin arch roof"will be the optimum cross section of the supporting structure;(3)According to the modeling and analysis method,an allowable deformation and safety factor can be determined for each excavation section of the tunnel,and the initial supporting structure and opening can be evaluated segment by segment or bay by bay,which provides basis for safety management and control of construction.