铁山隧道和大垭口隧道的平面弹塑性有限元分析

对巴彭公路铁山隧道和开万公路大垭口隧道的两个典型剖面的稳定性进行了平面弹塑性有限元计算,分析了围岩中的应力、变形、塑性区以及初期支护和二次衬砌结构的承载能力，得出了相应的认识：（1）在特定的埋深、岩体类别、支护结构及荷载释放比例的条件下，洞室周围有较强的应力集中现象，一定部位及范围内的围岩进入了塑性状态；（2）喷层、二次衬砌及锚杆均在弹性范围内工作，并且有较大的安全储备。

2D elastoplastic finite element analysis of stability of surrounding rock-supporting systems of Tieshan Tunnel and Dayakou Tunnel

By using the 2D elastoplastic finite element computations for the stability of two classical sections of Tieshan Tunnel and Dayakou Tunnel, the authors analyse the stresses, displacements and plastic zones in the surrounding rockmasses and the bearing capacities of the initial supports and the second linings; and obtain the relative knowledge: (1) under the special conditions of overburden thicknesses, rockmass types, support structures and loading relaxation ratios, stronger stress concentrations occur at the nearby regions of the tunnel walls, and some parts of the surrounding rockmasses enter plastic states; (2) all the shotcretes, second linings and rock bolts work within the elastic range, and have larger safety reserves.