地下混凝土排水管服役寿命概率分析

发布时间：2018-06-06 16:49

本文选题：混凝土排水管 + 腐蚀环境　；参考：《广西大学学报(自然科学版)》2016年06期

【摘要】：混凝土管道作为城市地下污水排放的主要结构,常常因受到H2S侵蚀致使管壁变薄而影响其服役寿命,并造成巨大经济损失。混凝土排水管中H_2SO_4和Ca(OH)_2之间的化学反应是造成其结构退化的主要因素。因量化混凝土排水管腐蚀的参数通常具有随机特点,因此,腐蚀深度增长(或称排水管壁厚的损失,下同)表现出明显的不确定性。而对于贯穿城市地下的混凝土排水管这样的大长度结构,确定性分析会产生较大误差,不能满足实际要求,为此,采用可靠性分析的方法,运用已有的混凝土排水管腐蚀增长确定性方程,建立基于Gamma随机过程的混凝土排水管内管壁腐蚀增长发展的不确定性方程,通过两种方程的综合使用,得到较符合实际的失效概率与服役寿命之间的关系,并运用蒙特卡罗模拟法来验证Gamma随机过程的准确性。利用敏感性分析技术,研究随机变量对结构腐蚀程度的影响。研究结果表明:H2S的浓度、混凝土排水管中水流面的最大宽度与未遇水的内管壁周长的比值、管道材料性能系数这三个参数对混凝土排水管腐蚀程度有较大影响。研究成果可为城市管理者们或工程师们对既有混凝土排水管进行较好的可靠性评估与服役寿命预测,为优化维修方案、降低维修成本提供较好决策依据。
[Abstract]:As the main structure of urban underground sewage discharge, concrete pipeline often affects the service life of pipe wall due to H _ 2S erosion and causes huge economic losses. The chemical reaction between H _ 2SO _ 4 and CaOH _ 2 in concrete drains is the main cause of structural degradation. Because the corrosion parameters of concrete drain pipes usually have random characteristics, the corrosion depth increases (or the loss of wall thickness of drain pipes, the same below) shows obvious uncertainty. However, for large length structures such as concrete drains running through the city's underground, deterministic analysis will produce large errors and cannot meet the actual requirements. Therefore, the reliability analysis method is adopted. Using the existing deterministic equation of corrosion growth of concrete drain pipe, the uncertainty equation of corrosion growth of inner wall of concrete drain pipe based on Gamma stochastic process is established, and the two equations are used synthetically. The relationship between failure probability and service life is obtained, and the accuracy of Gamma stochastic process is verified by Monte Carlo simulation. The influence of random variables on the corrosion degree of structures was studied by using sensitivity analysis technique. The results show that the concentration of H _ 2S, the ratio of the maximum width of the flow surface to the circumference of the inner wall of the concrete drainage pipe, and the performance coefficient of the pipe material have great influence on the corrosion degree of the concrete drainage pipe. The research results can be used to evaluate the reliability and service life of existing concrete drainage pipes for city managers or engineers, and to provide a better decision basis for optimizing maintenance schemes and reducing maintenance costs.
【作者单位】：华东交通大学土木建筑学院;
【基金】：国家自然科学基金资助项目(51378206) 国家重点基础研究“973”计划(2011CB612210)
【分类号】：TU992

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