新建隧道下穿运营公路引起的路面沉降控制基准

针对如何合理制定隧道建设引起的路面沉降控制基准的难题,以行车舒适性控制标准为出发点,同时考虑既有公路的不平整度和隧道建设引起的路面沉降槽形态特征,基于理论推导提出了一个较完整的解决方案. 首先,选择行车竖直方向上振动加速度为舒适性指标；其次,采用理想正弦函数加以刻画公路路面纵断面曲线,通过求导得到行车竖直方向振动加速度与既有公路的纵断面曲线特征参数的关系；再次,用Peck公式描述隧道建设引起的路面沉降槽形态特征,通过求导得到行车竖直方向上振动加速度与沉降槽形态参数的关系；然后,根据叠加原理可得到行车最大竖直方向上振动加速度的计算公式,该公式考虑了既有公路的不平整度和隧道建设引起的路面沉降的影响；最后,基于加速度值与人体主观感觉的关系,提出了路面沉降控制基准确定公式. 结果表明:行车舒适性与既有公路纵断面曲线的波长成正比,与振幅成反比；行车舒适性与路面沉降槽宽度系数成正比,与隧道中心线处路面最大沉降值成反比；行车舒适性与行车速度的平方成反比例. 通过适当降低行车速度是放宽沉降控制基准的有效方法.

Control standard for settlement of pavement caused by a new tunnel passing underneath an existing highway

It is a big problem to reasonably formulate the control standard for settlements of pavement caused by tunnel construction. To address this problem, this study proposed a complete solution based on strict theoretical deduction, which took the driving comfort control standard as the starting point, and considered both the roughness of existing highway and the morphological characteristics of pavement settlement trough caused by tunnel construction. First, the vertical vibration acceleration was selected as the comfort index. Second, the ideal sinusoidal function was used to depict the longitudinal curve of highway pavement, and the relationship between the characteristic parameters of the existing highway longitudinal curve and the vertical vibration acceleration was revealed by derivation. Third, the Peck formula was applied to describe the morphological characteristics of pavement settlement trough induced by tunneling, and the relationship between the morphological characteristic parameters and the vertical vibration acceleration was obtained by derivation. Fourth, the formula for calculating the maximum vertical vibration acceleration was established by incorporating the overlapping effect of the existing highway roughness and the pavement settlement induced by tunneling. Finally, based on the relationship between the acceleration value and the subjective feeling of human body, the formula for determining the control standard of pavement settlement was proposed. Results show that the driving comfort was directly proportional to the wave length of the existing highway longitudinal curve and inversely proportional to its amplitude; the driving comfort was directly proportional to the width coefficient of the settlement trough and inversely proportional to the maximum settlement value of the pavement at the tunnel center line; and the driving comfort was inversely proportional to the square of the driving speed. Therefore, an effective way to relax the settlement control standard is to reduce the driving speed properly.