震后偏压坡积体免刷坡进洞施工力学效应分析

结合震后四川某地特长高速公路隧道洞口施工的实际工程,针对其提出的免刷坡进洞施工技术,开展震后偏压坡积体免刷坡进洞施工力学效应的分析,通过FLAC 3D有限差分软件计算分析,结果表明:在施工过程要提前作好安全防护准备;左洞洞顶地表呈斜坡状,在剪切应力作用下导致初期支护外侧出现大范围受拉区;该工法可以有效地防止隧道上方坡积土体的滑动,保证施工安全且有效缩短进洞时间,对隧道周围地表植被破坏较小。

Mechanics Analysis of Tunnel Portal Construction without Treatment to Biasing Slope after Earthquake

With reference to the practices in portal construction of a highway tunnel in Sichuan where tunnel portal construction without treatment to biasing slope after earthquake,a mechanics analysis is conducted with finite difference software FLAC 3D of such tunnel portal construction.The results show that protective measures must be taken before the construction and a wide tensile zone is created outside the primary support due to shear stress generated by the tilted surface above the tunnel top and the method can effectively prevent the soil above the tunnel from sliding,which not only ensures safe construction and but also shortens the time to get into the tunnel with less destruction to the vegetation around the tunnel.