高速铁路合分修隧道合分修长度的计算方法与参数优化

摘要

根据过渡曲线线间距加宽起点位于直线还是圆曲线,高速铁路合分修隧道过渡曲线的线型分为Ⅰ类过渡曲线和Ⅱ类过渡曲线.依据过渡曲线线间距加宽设计理论,分别建立2类过渡曲线的直角坐标系,推导过渡曲线里程范围内过渡曲线上任意一点的线间距与其里程的函数表达式;在此基础上给出合分修长度的计算方法,并分析合分修长度与过渡曲线参数的关系.结果表明:对于Ⅰ类过渡曲线,内侧圆曲线半径宜大且不应小于9 000 m,外侧宜小且不应大于10 000 m,内外侧曲线应避免采用相近的圆曲线半径,不宜选取9°～12°的线路转角;Ⅱ类过渡曲线合分修长度不受圆曲线半径、线路转角等因素的影响;尽管采用Ⅰ类过渡曲线时合分修长度明显大于采用Ⅱ类过渡曲线时,但有利于降低合分修段施工风险,因此建议优先采用Ⅰ类过渡曲线.结合沪昆客运专线壁板坡隧道和凤凰山隧道的合分修段,验证了高速铁路合分修隧道合分修长度计算方法的正确性和有效性.%According to the widening starting point position which is on the straight line or circular curve for transition curve spacing,the transition curve of the composite repair tunnel for high speed railway is divided into type Ⅰ and type Ⅱ transition curves.Based on the design theory for the space widening of transition curve,the Cartesian coordinate systems of 2 types of transition curves are respectively established to derive the function expression for the line spacing of any point on transition curve and its mileage within the mileage range of transition curve.On this basis,the calculation method for the length of composite repair can be obtained.Then the relationship between the length of composite repair and the parameters of transition curve is analyzed.Results show that,for type Ⅰ transition curve,the inner radius of circular curve should be longer and not less than 9000 m.The outer radius should be shorter and not more than 10000 m.The inside and outside curves should avoid using similar radius of circular curve,and the angle of avertence in transition curve shouldn't adopt 9 to 12 degrees.For type Ⅱ transition curve,the length of composite repair is not affected by the radius of circular curve and the angle of avertence in transition curve.Although the length of composite repair for type Ⅰ transition curve is significantly greater than that for type Ⅱ transition curve,it helps to reduce construction risk in composite repair section.Therefore,it is recommended to adopt type Ⅰ transition curve first.The correctness and validity of the calculation method for the composite repair length of the composite repair tunnel for high speed railway are verified through the composite repair sections in Wainscot Slope Tunnel and Fenghuangshan Tunnel on Shanghai-Kunming passenger dedicated line.