【摘要】 为解决现行道路路线设计规范中高速公路连续长、陡下坡设计未将坡度及坡长与设计速度进行联系、以及现行规范是基于确定性思想进行设计的问题，利用温度指标来表征货车制动失效的程度，通过分析货车下坡时制动不失效、制动性能衰退但不明显以及制动完全失效这3种情况下制动毂的温度，引入了可靠度理论，建立了货车制动毂温度与速度、质量的功能函数，用可靠概率来表征货车在这3种情况下能安全下坡的坡长安全程度。考虑高速公路80,100,120 km/h设计速度下货车在3%,4%,5%平均坡度下行驶，制动毂温度分别达到200,220,260℃,基于可靠度理论，利用蒙特卡洛法进行计算，得到了可靠度概率大于95%对应设计速度与坡度的安全坡长、一般安全坡长、极限安全坡长。结果表明：一定设计速度下，坡度一定时，坡长越长，货车发生制动失效的概率越高；80,100,120 km/h设计速度下，3%,4%,5%坡度所计算得到的极限安全坡长值均比现行道路路线设计规范小，现行规范所规定的长、陡下坡坡长值偏于危险；设计速度越大，与规范所规定的坡长值差值越大。最后结合工程实例，验证了事故率与坡长可靠概率的关联，坡长可靠度越高，事故率越低。更多还原

【Abstract】 In order to solve the problems that the design of expressway with continuous long-steep downhill in the current road route design code does not link the slope and the slope length with the design speed, and the current code is designed based on the deterministic idea, the temperature indicator is used to describe the degree of brake failure of freight cars, and the temperature of brake hub is analyzed under the conditions of no brake failure, no obvious brake performance degradation and complete brake failure, the reliability theory is introduced, and the function functions of brake hub temperature, speed and mass are established. Considering the average gradient of 3%, 4% and 5% at 80,100 and 120 km/h, the temperatures of the brake hub reach 200,220 and 260 ℃ respectively, on the basis of the reliability theory, the Monte Carlo method is calculated, the safety slope length, general safety slope length and ultimate safety slope length corresponding to the design speed and slope with reliability probability greater than 95% are obtained. The result shows that:(1) the longer the slope is, the higher the probability of brake failure is;(2) at 80,100,120 km/h, the average length of limit safety slope calculated with 3%, 4%, 5% slope is smaller than the current road route design code, and the long and steep downhill slope is more dangerous;(3) the higher the design speed, the greater the difference from the slope length specified in the code. Finally, the relationship between the accident rate and the reliability probability of slope length is verified by an engineering example, the higher the reliability of slope length is, the lower the accident rate is.更多还原