地下混凝土排水管服役寿命概率分析  

A probability analysis on service life of underground concrete drainage pipes

作　　者：陈梦成[1] 戴一帆[1] 

机构地区：[1]华东交通大学土木建筑学院,江西南昌330013

出　　处：《广西大学学报（自然科学版）》2016年第6期1756-1763,共8页Journal of Guangxi University（Natural Science Edition）

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)

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。As a main structure of city underground sewage system,concrete pipes are often eroded by H2 S,which decreases their wall thickness,degrades their service life,and causes enormous economic losses. The chemical reaction between H2SO4 and Ca（ OH）2in concrete is a main factor causing the degradation of the structure. Since the parameters to quantify concrete drainage pipe corrosion usually have randomness,the increase of corrosion depth（ a. k. a. the thickness loss of drain pipe wall,similarly hereinafter） shows obvious uncertainty. For such long and large underground concrete drainage pipes through the city,the deterministic analysis will lead to large errors,and cannot meet actual requirements. Therefore,a probabilistic analysis method was proposed. A probabilistic equation of the corrosion growth in concrete drain pipe based on the Gamma stochasticprocess was developed,in conjunction with a present deterministic equation on corrosion growth of concrete drain pipe,to obtain an actual relationship between failure probability and service life. The Monte Carlo method was used to verify the accuracy of the Gamma stochastic process model. The sensitivity analysis technique was used to study the influence of random variables on the corrosion depth of the structure. The results show that the dissolved sulphide concentration,the ratio of the surface area of the stream to the area of the exposed pipe wall,the acid-consuming capability have a great influence on the corrosion degree of the concrete sewage pipe. The present results provide managers or engineers with reliability assessment and service life prediction for present concrete drainage pipes,and also benefit decision-making in optimizing maintenance program and reducing maintenance cost.

关 键 词：混凝土排水管 腐蚀环境 随机分析 敏感性分析 

分 类 号：TU992[建筑科学—市政工程]