【摘要】 所谓共同沟,即通常所说的地下综合管沟或管廊,是专门用于集中敷设各种市政管线的地下隧道。与传统直接埋地的敷设方式相比,共同沟是一种先进的敷设方式。按相似原理和“最不利原则”设计模型实验,采用甲烷模拟共同沟(狭长空间)中天然气管道的微小泄漏,分析了甲烷的泄漏量和模型的断面宽度对纵向布置的探头报警时间的影响,提出了“单宽泄漏量”的概念,并得出了模型实验的相似条件。根据实验数据的走势,采用抛物线函数进行数据拟合,最终得出报警响应时间的经验公式。更多还原

【Abstract】 Utility tunnel is an integrated underground pipe ditch or pipeline corridor, which is especially used for laying of underground tunnel of municipal pipeline project. Different from traditional direct burial laying method, utility tunnel is an advanced laying method. Model experiment was designed, in according to the similarity theory and disadvantage principle, to simulate minute leakage of natural gas pipe in utility tunnel (narrow-long space) by use of methane. The influences of the leakage flux of methane and the width of cross-section on alarm time of detectors positioned longitudinally was analyzed. The concept of "leakage flux per unit width" was proposed, which was defined as the ratio between leakage flux of methane and width of model section. Meanwhile, the similar condition of the model experiments was obtained. On the basis of the distribution characteristic of experimental data, parabola function was used as the fit function of alarm response curve. Finally, the empirical formula of alarm time was obtained.更多还原