管幕预支护隧道施工变形特性相似模型试验研究

基于相似理论分析管幕结构模型试验的相似关系,通过试验合理选取和配制了相似模型试验材料,考虑管幕横向连系进行了管幕预支护隧道相似模型试验,研究了不同管幕布置型式、不同管幕间距、不同管间横向连系等情况下,隧道开挖引起管幕结构和地层变形特性。研究结果表明,在当前模型尺寸条件下,"门"字形管幕施工比"口"字形管幕引起地层变形增大28.3%左右,大间距管幕施工引起的地层变形值比小间距增大约10%,不考虑横向连系管幕施工引起地层变形显著增大,其相对于有横向连系工况变形增大约30%。实际工程中建议采用小间距、"口"字形布置的管幕,并加强管幕间的横向连系,可有效控制管幕结构和周边地层的整体变形。

Similar Model Study on Deformation Characteristics of Tunnel with Pipe-Roof Reinforcement during Construction

Based on the similarity theory, the similarity of the model test of tunnel with pipe-roof reinforcement was analyzed, and the similar model test materials were selected reasonably by means of experiment. The similarity model test has been carried out considering the transverse connection of pipe-roof. The deformation characteristics of the structure during tunnel excavation have been studied under different conditions, such as the arrangement of the different types of the pipe roof, the distance between the different pipe roof and the transverse connection between the pipes. The results show that, under the condition of setting model size, the deformation of "gate" shaped pipe roof is about 28.3% higher than that of "mouth" shaped pipe roof, the deformation of pipe roof with large spacing of 40mm increased by about 10% compared with the small spacing of 20mm. And the deformation is increased significantly without considering the transverse connection of pipe-roof, which increases by about 30% compared with the transverse connection condition. The pipe-roof project with small spacing and "mouth" shaped arrangement is preferred in practical engineering. And the transverse connection of pipe roof should be strengthened, which can effectively control the deformation of the whole pipe roof structure and the surrounding ground.