钢管混凝土加固盾构隧道管片接头受力性能试验研究

管片接头是盾构隧道结构的薄弱部位，对结构的综合性能起着控制作用。为了研究其受力性能，开展了8个足尺管片接头试件在正、负弯矩作用下的静力试验，其中4个试件采用钢管混凝土加固，另外4个为对比试件(2个采用传统钢板加固，2个未加固)，得到了正、负弯矩作用下不同试件的破坏模式；在用钢量相近的条件下，对钢管混凝土加固和传统钢板加固进行了比较，考察了钢管混凝土截面高度对加固效果的影响。研究表明：正、负弯矩作用下，钢管混凝土加固均能显著提升管片接头的受力性能；正弯矩作用下，钢管混凝土的加固效果全面优于传统钢板加固效果；负弯矩作用下，钢管混凝土加固试件的接头张开量在化学锚栓断裂之前明显小于传统钢板加固试件的；钢管混凝土的截面高度从45mm增至60mm，加固效果并未进一步提升。

Experimental study on mechanical performance of tunnel segment joints strengthened using concrete-filled steel tubes

Segment joints are the weak parts of shield tunnel structure, and play a controlling role on the overall performance of the structure. This paper presented an experimental study on eight full-scale segment joints, including four joints strengthened by concrete-filled steel tubes (CFSTs), two joints strengthened by traditional steel plates (TSPs), and two unstrengthened joints served as control specimens. The failure modes of different specimens under the action of positive or negative bending moment were revealed, the strengthening effect of the specimens strengthened using CFSTs and that of the specimens strengthened by TSPs were compared under the condition of similar steel content in both cases, and the influence of the sectional height of CFSTs on the strengthening effect was examined. The test results show that the mechanical behavior of the segmental joints subjected to sagging or hogging moment can be significantly improved by using CFSTs. In the sagging moment case, the strengthening effect related to CFSTs is overall superior to that pertaining to TSPs, while in the hogging moment case, the joint opening of the specimens strengthened using CFSTs is remarkably smaller than that of the specimen strengthened by TSPs before the fracture of anchor bolts. With the increase of the sectional height of CFSTs from 45mm to 60mm, the strengthening effect does not further improve.