大变形埋地钢管结构承载能力及修复方法研究  

Structural Bearing Capacity and Rehabilitation Method of Buried Steel Pipes Subjected to Large Deformation

作　　者：于金弘 伍鹤皋[1] 石长征[1] 李东明[2] 靳红泽[2] Yu Jinhong;Wu Hegao;Shi Changzheng;Li Dongming;Jin Hongze(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 430072,China;National Center of Quality Inspection&Testing for Hydraulic Metal Structure,Ministry of Water Resources,Zhengzhou 450044,China)

机构地区：[1]武汉大学水资源与水电工程科学国家重点实验室,武汉430072 [2]水利部水工金属结构质量检验测试中心,郑州450044

出　　处：《天津大学学报（自然科学与工程技术版）》2022年第4期419-427,共9页Journal of Tianjin University：Science and Technology

基　　金：国家自然科学基金资助项目(51409194).

摘　　要：大直径埋地钢管在大型引调水及水电工程中应用广泛,但施工过程中钢管易出现超出规范要求的大变形,而国内外对大变形埋地钢管的结构特性及处理措施研究较少.本文以某环变形达8.9%的埋地钢管为例,基于现场测试结果,采用数值模拟技术反演了该工程的施工过程,分析了该大变形管道若直接投入运行后的变形、应力及塑性情况,进而结合工程实际提出了水压法修复,并与传统的内撑法修复进行了比较研究.结果表明:大变形埋地钢管承受了较高的弯曲应力且管周土体支撑不足,结构承载能力较弱,荷载作用下钢管的变形和应力会大幅增加,安全风险较大.设置加劲环虽能增加钢管的抗外压稳定,但对管壁应力不利,高应力及塑性区域主要集中在管顶、管腰和管底及加劲环附近.大变形埋地钢管虽不符合规范要求,但不必更换钢管,可考虑对其进行修复,以降低钢管变形并提高管周土体模量,修复方法可采用内撑法或水压法.内撑法采用千斤顶将钢管顶圆,在顶撑区易产生应力集中,适用于管线局部发生大变形的情况;水压法利用内压复圆原理,可使管壁受力均匀,长距离管线下使用更为方便,修复后应检测并修补焊缝及防腐措施,并对运行期管道做好监测工作.研究成果可为类似工程处理及后续规范编制提供借鉴和参考.Large-diameter buried steel pipes are widely used in major water diversion and hydropower projects.These pipes are prone to excessive deformation during the construction process.A few reports investigating their structural characteristics and treatment measures globally have been reported.Herein,a buried steel pipe with a ring deforma-tion of 8.9%was studied as an example.Based on the results of field tests,the project’s construction process can be inverted using numerical simulation.The steel pipe’s deformation,stress,and plasticity in subsequent operations are analyzed.Furthermore,a pipe rehabilitation method using the water pressure method is proposed according to the engineering situation.A comparative study is also performed using the traditional jacking method.The results show that the large deformation buried steel pipe has high bending stress and insufficient soil support.Thus,its structural bearing capacity is weak,posing a significant safety risk.Under the action of a load,the steel pipe’s deformation and stress increase considerably.Although a stiffening ring can improve the steel pipe’s stability against external pres-sure,it is unfavorable for the stress of the pipe wall.High stress and plastic areas are concentrated mainly near the pipe invert,springline,crown,and stiffening ring.Although the large deformation buried steel pipes do not satisfy the specification requirements,their replacement is unnecessary;instead,they can be rehabilitated to reduce de-formation and improve the soil modulus around them.The jacking or water pressure methods can be used for rehabili-tation.The jacking method involves rounding the steel pipe with jacks and is suitable for locally deformed pipe seg-ments,but the pipe has stress concentration in the bracing area.The water pressure method employs the principle that internal pressure can reduce the pipe deformation,which makes the pipe stress uniform.This method is more conven-ient for long-distance pipelines.In addition,the welds and anticorrosion materials should

关 键 词：埋地钢管 大变形 结构承载 修复 内撑法 水压法 

分 类 号：TU432[建筑科学—岩土工程] TV37[建筑科学—土工工程]