弧形排桩—连系梁抗滑结构加固隧道口滑坡应用研究及优化设计

因隧道洞口所在坡体产生滑坡,导致隧道洞口附近衬砌发生变形破坏。为控制隧道衬砌变形破坏,采取增加型钢,加强隧道衬砌的补救措施。但在滑坡推力作用下,型钢发生不同程度的变形破坏,故此,单独加固隧道衬砌并不能有效控制隧道变形。拟采用抗滑桩加固隧道所在滑坡体,通过增加抗滑力控制隧道变形。因单桩抗滑能力有限,为保证提供足够的抗滑力,需要加大桩身截面尺寸,增加桩长,甚至增加桩数减小桩间距及增加排数,如此,会增加施工难度,提高工程造价;而通过在桩顶设置连系梁,使各桩联合作业形成整体,可提高抗滑能力。该库岸滑坡坡面与水面交界处成弧形分布,依据坡面地形将抗滑桩按弧形布置,桩顶设置弧形连系梁,并在连系梁两端设置高强度抗力桩限制其端部位移。通过具体工程实例计算分析,比较连系梁刚度对抗滑结构内力分布的影响规律及加固效果。

The Application Research and Optimization Design of Row Piles with Coupling Beam Strengthened Structure on Landslide at Tunnel Portal

The slope at tunnel portal is likely subject to landslide and lead to deformation and failure of lining around the tunnel portal. In order to control the deformation of the tunnel lining,the measure to strengthen the tunnel lining with additional formed steels is taken. However,the formed steels suffer deformation and failure of different degrees under the landslide thrust,so strengthening the tunnel lining alone cannot control the deformation effectively,while,the anti-slide pile can do the job. As the resistance of single pile is limited,in order to ensure the adequate sliding resistance,it is required to increase the pile section,the length of pile,the number of pile,and even the row of pile,which will result in higher project cost and more difficulties in construction. By adding coupling beam on the top of anti-slide piles can improve the resistance force with the integration of all piles working together. The intersection of the landslide and water surface is distributed in arch form,according to the actual situation,the measure of arc row piles with arc coupling beam on pile top can be taken to strengthen the landslide,at the same time,high strength resistance piles is set up on both ends of the coupling beam to limit the deformation. Through engineering example,the internal forces of the anti-slide structure and the reinforced effect are analyzed under the influence of stiffness of the coupling beam.