用加速度方法计算隧洞的安全系数

地下隧洞的破坏面和破坏方式与常规边坡不同，所以边坡稳定分析中经典的方法难以直接应用到地下隧洞的稳定分析中。文章引申了加速度计算的思路，结合强度折减的概念，提出了以加速度的模最小为条件来计算隧洞破坏面安全系数的方法。并且采用以极坐标表示的光滑连续曲线来构造破坏面，用连续蚁群算法搜索最小安全系数和临界破坏面，从而提出了基于加速度方法计算隧洞安全系数的新的思路。这种方法概念明确，且与边坡安全系数计算具有相同的理论基础。算例计算也表明了它的有效性。

Acceleration-based safety factor calculation of underground tunnels

For the underground tunnel, it is difficult to evaluate its stability using the classical analysis method applicable to soil slopes, since its failure surface and failure mode are very different from those of the slopes. In this paper, incorporated with the concept of strength reduction, the approach of calculating acceleration is extended to evaluation of the safety factor of underground tunnels, which is defined as the reduction factor that minimizes the magnitude of acceleration. We generate the failure surface using a smooth continuous curve expressed in polar coordinates, and adopt ant colony optimization for continuous domains to search the minimum safety factor and critical failure surface. Thus, what we are developing is actually a new explicit method for calculating the acceleration-based safety factor of underground tunnels. It has the same theoretical basis as those for calculating the safety factor of slopes, and is shown to be effective through a case study of the stability analysis of an underground tunnel.