层状围岩管片衬砌配合陶粒与锚杆的联合支护技术研究

Combined support technology of segment linings with compressible crushed stone and anchor bolts in layed rock

深部层状围岩中修建盾构隧道,管片衬砌易受偏压作用,对结构安全构成挑战。提出一种管片衬砌配合陶粒可压缩层与锚杆的联合支护技术,采用大比例尺相似模型试验针对联合支护技术的支护效果进行研究,进行了可压缩层配合不同长度和间距的锚杆支护效果对比研究,从管片衬砌内力、变形角度分析了联合支护效果,从可压缩层的压缩变形路径和移动特征角度分析了联合支护机理。研究结构表明：联合支护技术一定程度上改变了管片的内力分布形式,降低了围岩偏压作用,削减管片衬砌内力和形变量;锚杆的施作可以有效减小层状围岩变形,陶粒压缩层可以有效吸收围岩变形;联合支护中锚杆的长度和间距存在一个最优值,超过该最优值,锚杆的加固效果不再明显增加;联合支护的作用机理由两部分构成：陶粒压缩层的让压作用与锚杆加固作用。研究结果对层状围岩中修建盾构隧道的支护结构型式设计具有一定参考价值。

The segment lining is susceptible to unsymmetrical pressure when a shield tunnel is constructed in deep layered rock. A new support technology of segment linings combined with compressible ceramic and anchor bolts is proposed. In order to study the effect of the support technology, similar model tests are carried out to study the support effect of segment linings with compressible ceramic and anchor bolts with different lengths and spacings. The internal force and deformation of the segment linings are analyzed, and the mechanism of the combined support is revealed from the deformation path of compressible ceramic. The results show that the combined support technology can change the internal force distribution of the segment linings to some extent and can also reduce the biased pressure of the surrounding rock. The application of the bolts can effectively reduce the deformation of the layered rock, and the compressible ceramic can effectively absorb the deformation. There are optimum values of the length and the spacing of the bolts in the combined support, and beyond the values, the reinforcement effect of the bolts will not increase obviously. The mechanism of the combined support consists of two parts： the yielding effect of the compressible ceramic and the reinforcement effect of the bolts. The results of this study have certain reference value for the support design of the shield tunnels in layered rock.