中文摘要：

城市内新建工程周边环境复杂,地下管线种类繁多,在设计之初就需要考虑施工以及工程营运对其安全的影响,但目前缺乏统一的影响评价标准,须按照管线功能以及所属部门的相关规程作为其评价依据。该项目的管线为下穿围堰的2条直径为1.2 m、壁厚为12 mm的排污管,采用FLAC3D建立了围堰工程对大直径有压焊接薄壁排污管道的三维数值计算模型,分4种不同施工工况进行了管道变形和应力计算。依据相关规范的要求,从管道本身的安全性和正常使用要求出发,并采用第4强度理论计算了相当应力,最大值为136.61 MPa,出现在最后抽水工况下管1的外侧。最大沉降量39.3 mm对应的管体倾斜量为0.275%。将其结果与理论值进行对比,理论计算得到的相当应力最大值为188.18 MPa,高于数值计算结果,其原因为理论方法将各影响效应分别计算并进行简单相加。结果表明,拟建围堰工程对该管线的影响可控,数值方法较规范方法计算结果更为合理,为类似工程对管线影响评价提供了参考。

英文摘要：

There are a lot of kinds of underground pipes and structures in the urban area; the safety and regularly running of which must be taken into account during newly constructions. There are no generalized criterions to evaluate the safety and regularly running of them at present. It should be investigated which sectors the pipes belong to before construction, then their design and construction specifications can be used in the safety evaluation. Drainage design specifications are used to evaluate the safety of 2 large diameter steel sewage pipes with diameter of 1.2 m and thickness of 12 mm, during the cofferdam construction in the Litchi River in Guangzhou city. In view of the calculation methods in the design specification can not consider the interactions of all the effects during the construction. A three-dimensional simulation model of the whole cofferdam construction field stratum with the 2 large diameter steel sewage pipes is established. Deformation and stress of the pipes under 4 different construction conditions are calculated with FLAC3D. The equivalent stresses are calculated by fourth strength theory. The maximum value is 136.61 MPa, which appears at the outer surface of pipe No.1 under the last construction condition. The maximum settlement of the pipe is 39.3 mm, which produces 0.275% declination of the pipe. The maximum stress value calculated by theoretical calculation formulas is 188.18 MPa, which is much higher than the result calculated by the current codes. The reason is that every effort is calculated independently and simply added in the theoretical methods. Finally, Deformation and strength of the pipes are checked according to relevant Chinese standards. It reveals that the sewage pipe lines are safe in the construction procedure and the results got by numerical simulation are more reasonable than those calculated by theoretical formulas.