G7高速公路金盆湾隧道初支大变形病害处治技术应用

Application of large deformation diseases treatment technology of G7 highway Jinpenwan tunnel beginning support

金盆湾隧道为全程Ⅴ级围岩大断面特长公路隧道,水文地质为松散覆盖层中孔隙水及基岩裂隙水。孔隙水主要赋存于第四系卵石、圆砾等碎石土及砂砾、粉砂等砂类土孔隙中。工程地质为围岩,主要为第四系粉土、漂石、卵石及白垩系上统助马堡组砂岩。第四系覆盖层结构松散,抗冲刷能力差,白垩系上统助马堡组砾岩成岩程度低,岩质较软,岩体极破碎,被雨水浸润易软化,围岩自稳能力差。无支护时拱部易产生坍塌,侧壁易产生掉块或失稳,按照大变形产生的机理可将大变形分为高地应力下软弱围岩中的大变形、膨胀性围岩大变形、断层破碎带松弛变形等几种,为典型大变形隧道。文章就金盆湾隧道实施大变形病害处治施工展开论述,为同行提供参考。

Jinpenwan tunnel is entire V level surrounding rock of large cross section extra -long highway tunnel, hydrogeology is loose covering layer pore water, bedrock fissure water. Pore water mainly occurs in the pore of quaternary gravel soil such as pebble, round gravel, and sand soil such as sand, silt sand. Engineering geology is surrounding rock, mainly for the quaternary powder soil, boulders and pebbles and cretaceous upper serious Zumabao sandstone. The structure of the quaternary overburden is loose, and erosion resistance is poor, cretaceous upper serious Zumabao conglomerate diagenetic degree is low, with soft rock, rock crushing, easy to soften in rain infiltration, self - stability of surrounding rock is poor. Without supporting arch are prone to collapse, and falling wall are prone to instability, according to the mechanism of large deformation, large deformation can be divided into large deformation in weak rock mass under high geostress, the large deformation of swelling surrounding rock, fault fracture zone relaxation deformation, is typical large deformation tunnel. This article discussed large deformation diseases treatment construction of Jinpenwan tunnel, provide reference for peers.