拼装式增强结构加固盾构纵缝力学特性试验

Experimental Study on Mechanical Behavior of Shield Segmental Joints Strengthened by Assembly Reinforced Structures

摘要:

内部加固技术是控制盾构衬砌环及局部接缝变形的有效方法，常用的加固技术多为在隧道内部添加钢板等结构，但具有加固后遮挡衬砌表面、不利于观察衬砌病害等缺陷。鉴于此，提出了一种拼装式增强结构，并对安装与未安装拼装式增强结构的盾构纵缝开展正、负弯矩试验研究。试验结果表明：拼装式增强结构对正、负弯矩承载的纵缝均具有一定的加固作用，在纵缝张开后，拼装式增强结构与螺栓共同承载，可限制接缝张开、提升接缝承载能力。但拼装式增强结构对纵缝在负弯矩荷载作用下的加固作用有限，不如正弯矩承载时明显，主要原因是该结构安装于接缝内弧面，对接缝内弧面的张开可以有效控制，对接缝外弧面的张开限制作用较小。另外，拼装式增强结构与管片连接位置周边的混凝土出现了破坏，该连接位置对于拼装式增强结构加固效果的发挥极为关键，需进一步优化。

Abstract:

The internal reinforcement technology is an effective method to control the deformation of shield segmental linings and local joints. The commonly used reinforcement technology is to add steel plates or other structures in a tunnel， but it has the defects of covering the lining surface after reinforcement， which is not conducive to the observation of lining diseases. Assembled reinforced structures were proposed in this paper， and positive and negative bending tests were conducted to study the mechanical properties of the segmental joints with and without the assembled reinforced structures. The experimental results show that the assembled reinforced structures have a certain reinforcement effect on the segmental joints bearing positive and negative bending moments. After the joints open， the assembled reinforced structures bear the load together with the bolts， limit the opening of the joints， and improve the bearing capacity of the joints. However， the reinforcement effect of the assembled reinforced structure on the joint bearing negative bending moment is limited and less obvious than that on the joint bearing positive bending moment. The main reason for this is that the structure is installed on the inner arc surface of the joint， which can effectively control the opening of the inner arc surface of the joint， but the opening restriction effect of the outer arc surface of the joint is small. In addition， the concrete around the connection positions between the assembled reinforced structures and the segments are damaged. The connection is critical for the reinforcement effect of the assembled reinforced structures， which， thus， needs to be further optimized.