甜永高速公路某黄土隧道仰拱开裂原因分析及处置措施

运营后的甜永高速公路某隧道，出现了仰拱开裂等现象，通过进行补充地质勘察、现场试验及监测后发现，引起仰拱开裂的主要原因为黄土在水的浸泡下地基承载力大幅度削弱，拱脚地基承载力不足，致使拱脚沉降导致仰拱起拱弯拉而产生裂缝，导致本隧道仰拱回填及调平层混凝土开裂。针对开裂原因，通过采取钢管桩地基加固+衬砌结构加强+增设盲沟排水系统工程处理措施，取得良好的治理效果。

Cause Analysis of Inverted Arch Cracking at a Loess Tunnel on Tianshuibao-Yonghe Highway and the Treatment Measures

There occurred cracks on an inverted arch of tunnel on Tianshuibao-Yonghe Highway in operation. With the added geological survey, field test and monitoring, the main cause of cracking was found out that, due to dramatically weakened bearing capacity of loess ground under water soak and the shortage of bearing capacity of the arch foot, flexural tensile failure came out at the inverted arch as the result of the settlement of arch foot, thus the concrete cracking at the backfill and leveling layer of the inverted arch appeared. For this cracking reason, the comprehensive treatment measures, including steel pipe pile foundation reinforcement, lining structure strengthening, and additional blind ditch drainage system added, were adopted, and got good effect at last.