Proposal on Design of Vertical Pre-Reinforced Bolt Method

在山岭隧道或浅埋隧道入口处隧道开挖过程中，有时会出现地表下沉、隧道断面坍塌或隧道上方边坡滑坡等问题。处理此类问题的辅助方法，称为“竖向预加固锚杆法”，适用于保持自然环境。然而，竖向预加固法的设计是根据地表移动与锚杆等效力的经验进行的。这不是一种充分评估加固效果以保护地面沉降和滑坡的方法。此外，从现场测量中阐明该方法的有效性的数据仍然很少。本研究旨在通过模型试验验证隧道下部水平以下加固构件的侵彻深度的有效性，目的是减少场地面积和施工成本。提出了竖向预加强锚杆的设计与施工建议，结果表明，竖向预加强锚杆在隧道开挖过程中表现为轴向加固模式，辅助地面拱形。隧道开挖荷载通过其加固有效地分布在隧道工作面的前方和侧面。本研究已完成。

During tunnel excavation in the area of the entrance of mountain tunnel or shallow tunnel, such many problems as subsidence of the ground surface and collapse of the cutting face of the tunnel or the land slide of the slope above the tunnel sometimes occur. The auxiliary method of coping with such problems, called "Vertical Pre-Reinforced Bolt Method," is adapted to keep the natural surroundings. However, the design of vertical pre-reinforced method based on the experience in respect of the equivalence force between ground movement and rock bolt. It is not a method for sufficiently evaluating the stiffening effect to protect a ground settlement and a land slide. In addition, there is still few data clarifying the effectiveness of this method from field measurements.This study was planned to verify the effectiveness of penetration depth of reinforce members below the bottom section level of the tunnel using model tests with the aim of reducing the width of site area and construction cost. The proposal of the suggested method on the design and construction of vertical pre-reinforced bolt method was pursued.As the result, the vertical pre-reinforced bolt behaved an axis reinforcement model to assist the ground arch of the ground by tunnel excavation. The load of tunnel excavation is effectively distributed in the front and side of the tunnel face by its reinforcement. This research is completed.