某黄土隧道病害原因分析及处治措施

某黄土公路隧道在通车运营几年后出现了衬砌开裂及隧道沉降病害。通过对该黄土公路隧道病害的监测及其发展过程的分析，得出黄土工程特性、地表水及黄土隧道埋深是造成隧道病害的主要影响因素。针对上述隧道病害，本文提出用有限元计算分析方法对4种不同工况下的加固方案进行分析，结果表明对结构的局部补强和对地表水的处理，结构与土体之间应力的传递和消散作用使得应力逐步得到调整与改善，最后对拱脚的加固使得隧道结构的整体性进一步加强，应力分布更加合理，承受荷载的能力进一步提高。故而本文提出，该隧道衬砌裂缝应进行修补加固，同时对拱脚地基采用树根桩和夯扩桩加固的方法可以提高隧道安全通行能力。

ANALYSIS OF DISEASE CAUSES AND TREATMENT MEASURES OF HIGHWAY TUNNEL IN LOESS

After having been operated for several years, a highway tunnel produces the diseases of lining cracks and tunnel settlement in loess area.  Analysis of the development process of  the diseases indicates that the main causes  are loess characteristics, surface water and the depth of loess tunnel. In response to the diseases, a finite element analysis is conducted  for four different conditions of the reinforcement  measures.  The numerical results show that the local structural reinforcement, surface water treatment, and the soil-structure interaction  can reduce stress concentration and improve the tunnel stress distribution.  The reinforcement  at the bottom corners of tunnel arch structures  can  strengthen the overall stress distribution more reasonable  and enhance the tunnel ability  to undertake external loading.  Hence, the tunnel lining cracks should be repaired and strengthened. At the same time,  the arch foot foundation should be reinforced with root pile and rammed-pedestal pile.  These measures would  improve the safety of the tunnel capacity.