盾构隧道管片接头采用SMA螺栓短期加固的试验研究

发布时间：2018-08-07 21:10

【摘要】：盾构法已广泛应用于地铁隧道中，已建成的地铁隧道可能因各种原因导致管片接头张开，进而引发边缘混凝土压碎、钢螺栓受拉屈服、漏水等严重问题。为此，本文提出了一种盾构隧道管片接头的短期加固方法，即当接头张开量过大时，将预处理过的形状记忆合金（Shape MemoryAlloy，简称SMA）螺栓装入相邻管片的预留孔中并加热，利用SMA的形状记忆效应为管片接头提供一定的闭合回复力，促使接头张开量减小从而为后续长期加固创造有利条件。本文对所提短期加固方法进行了初步研究，主要工作包括以下四个方面：（1）开展了SMA棒的回复力试验，为随后加固试验方案的确定提供了重要基础数据。研究表明：预拉应变5.80%时，本文所用SMA棒的控制回复应力的峰值可达380MPa左右，该回复应力峰值对应的温度约160°C。（2）提出了SMA棒的一种通电加热方法，通过加热试验验证了其有效性，比较了两种表面绝缘电热丝的加热效率。研究表明：第2种表面绝缘电热丝的加热效率明显高于第1种表面绝缘电热丝，，前者可在38min内将本文所用SMA棒加热至160°C。（3）开展了两组足尺盾构隧道管片接头的短期加固试验，验证了本文所提加固方法的可行性。研究表明：该加固方法可使管片接头张开量降低37%~62%，接头挠度减小21%~42%，混凝土受压区边缘应变降低87%~96%，钢螺栓受拉应变减小67%~74%；加固前接头张开量越小，加固效果越显著。（4）初步探讨了本文所提加固方法的工程应用问题，给出了相应的解决方法，表明其实际工程应用是可行的。
[Abstract]:The shield tunneling method has been widely used in subway tunnel, and the completed subway tunnel may cause segment joint to open for various reasons, which may lead to serious problems such as edge concrete crushing, tensile yield of steel bolt, water leakage and so on. In this paper, a short term reinforcement method of shield tunnel segment joint is proposed, that is, when the opening of the joint is too large, the pretreated shape memory alloy (Shape MemoryAlloy,) bolt is put into the reserved hole of adjacent segment and heated. The shape memory effect of SMA is used to provide a certain closed recovery force for the segment joint, which can reduce the opening of the joint and create favorable conditions for the subsequent long-term reinforcement. In this paper, the proposed short-term reinforcement methods are studied. The main work includes the following four aspects: (1) the restoring force test of SMA rod is carried out, which provides important basic data for the determination of the subsequent reinforcement test plan. The results show that when the pretension strain is 5.80, the peak value of the controlled recovery stress of the SMA rod used in this paper can reach about 380MPa, and the temperature corresponding to the peak value of the recovery stress is about 160 掳C. (2) an electric heating method for the SMA rod is proposed. The heating efficiency of two kinds of surface insulated electric heating wire was compared by heating test. The results show that the heating efficiency of the second kind of surface insulated electric heating wire is obviously higher than that of the first kind of surface insulated electric heating wire. The former can heat the SMA rod used in this paper to 160 掳C. (3) two groups of short-term reinforcement tests on the segment joint of full-scale shield tunnel have been carried out, and the feasibility of the proposed reinforcement method has been verified. The results show that this reinforcement method can reduce the opening amount of segment joint by 37% and 62%, decrease the deflection of the joint by 21% and 42%, reduce the strain at the edge of concrete compression zone by 87% and 96%, decrease the tensile strain of steel bolt by 6774%, and decrease the opening amount of joint before reinforcement. The reinforcement effect is more remarkable. (4) the engineering application of the reinforcement method proposed in this paper is discussed, and the corresponding solution is given, which shows that the practical engineering application is feasible.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.43

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