【作者】 易瑞吉；

【导师】 程和森；

【作者基本信息】 南京水利科学研究院 ， 水利水电工程， 2007， 硕士

【摘要】 钢板衬砌砼结构为水利、水电等工程普遍采用。当砼浇注施工质量不好时,在钢板与砼之间会产生脱空缺陷,严重时会威胁工程运行安全。长期以来,人们曾采用x-射线、γ-射线和超声波方法进行探查尝试,但都未能奏效。目前工程上只能采用较原始的槌击法检查,常因误判而造成钢结构的不必要的破坏。鉴于此,本文提出利用快中子散射法无损探测脱空缺陷,以解决这一工程难题,做了以下研究工作:a)通过对快中子与钢板和砼两种不同介质作用时的机理研究,了解复合界面层快中子慢化的差异性;b)以大量室内模拟标定试验为依据,确定了结合面脱空缺陷空间形态与所形成的热中子浓度(计数率)大小和分布之间关系;c)采用缺陷分割,分块对比分析,实现了脱空检测结果的数字化显像;d)以天生桥一级电站工程4~#蜗壳为例,验证了钢板与浇注砼结合面脱空缺陷中子无损探测及结果数字显像方法在实际应用中的可行性。更多还原

【Abstract】 Concrete structure overcasted by steel plate is widely adopted in hydraulic and hydroelectric engineering. If the concrete is poorly poured there will be come-away defect between the steel plate and concrete, which threats the running safety of the project for severity. People have been long attempting to use x-ray,γ-ray and ultrasonic to make detection, but without any effect. At present, it can only use the relatively primitive mallet-striking way to examine the structure. But it often cause unwanted damage to the steel structure out of misjudgement. Whereas, this dissertation proposes to apply Fast Neutron Scattering to detect the cavity defects without any damage so as to resolve this difficult engineering problem, and hence the following research is made:a) Find out the moderation difference of fast neutrons inside the complex interface through the mechanism study of between fast neutrons and steel plate and also fast neutrons and concrete.b) On the basis of abundant laboratory simulation demarcate experiments, determine the spatial configuration of the cavity defect in complex interface, and along with the relation between thermal neutrons density （counting rate） and distributionc) Contrast analysis after defect division and partition realizes digitization image-display of the come-away examination result.d) Take the 4^th volute in Tianshengqiao 1^st Grade Power Station as example, validate the feasibility of digitization image-display as well as neutron non-damage detection of come-away defect inside the steel plate & concrete complex interface in practical application.更多还原