复杂条件下花岗岩残积土隧道支护结构力学特性研究

发布时间：2019-05-05 13:41

【摘要】：在我国湖南、江西、浙江等地区,特别是闽南地区,分布着大量花岗岩残积土,而花岗岩残积土具有遇水易崩解特性,因此在开挖花岗岩残积土隧道时要特别注意其围岩稳定性。本文基于国家自然科学基金项目“花岗岩残积土隧道开挖围岩崩解特性及其控制研究”,以福建省沙县高砂镇端西隧道为依托背景,采用室内相似模型试验和数值模拟方法,并结合现场拱顶监测数据,对花岗岩残积土隧道支护结构力学特性进行了研究,本文主要研究成果如下:(1)通过大量的调研、分析和相似比计算,选用配合比W/P=0.71、水泥掺量为4%、缓凝剂掺量为0.1%的水泥石膏作为衬砌的材料。经理论计算,隧道模型衬砌厚度为32mm。(2)基于相似比,设计了花岗岩残积土隧道模型,开展不同隧道埋深、围岩软化程度、加设超前锚杆后软化围岩对其影响研究。试验结果表明:随着埋深的不断增加,围岩压力、拱顶和地表沉降都先缓慢增加后急剧增加,说明隧道埋深越大,对其稳定性影响越大。同时发现,增加超前锚杆支护后,随注水量的增加,各监测点累计沉降量明显降低,而围岩周边各监测点的围岩压力却均匀增加,可见采用超前锚杆对其进行预支护是可行的。(3)结合依托工程,基于FLAC3D软件建立隧道洞口模型,在拱顶以下6.74m处,通过预设四组围岩初始孔隙水压力来软化围岩,并结合现场拱顶监测数据,探讨了围岩软化对花岗岩残积土隧道支护结构的影响。结果表明围岩软化对隧道的开挖十分不利,因此,开挖隧道前应及时处理。
[Abstract]:In Hunan, Jiangxi, Zhejiang and other areas of China, especially in southern Fujian, a large number of granite residual soil is distributed, and granite residual soil has the characteristics of easily disintegrating with water. Therefore, it is necessary to pay special attention to the stability of surrounding rock in excavation of granite residual soil tunnel. Based on the project of National Natural Science Foundation of China "study on collapse characteristics and Control of surrounding Rock excavation of Granite residual soil Tunnel", based on the background of Gaosha Town West Tunnel in Shaxian County, Fujian Province, the similar model test and numerical simulation method are adopted in the laboratory. In this paper, the mechanical properties of granite residual soil tunnel support structure are studied. The main research results are as follows: (1) through a lot of investigation, analysis and similarity ratio calculation, the mixture ratio of W _ (?) P ~ (?) (0.71) is selected, and the main results of this paper are as follows: (1) Cement gypsum with 4% cement and 0.1% retarder is used as lining material. Through theoretical calculation, the thickness of tunnel model lining is 32mm. (2) based on the similarity ratio, the granite residual soil tunnel model is designed. Different tunnel depth and softening degree of surrounding rock are carried out, and the influence of softening surrounding rock after setting advance anchor bar is studied. The experimental results show that with the increasing of buried depth, the pressure of surrounding rock, the settlement of arch roof and ground surface increase slowly at first and then increase sharply, indicating that the greater the buried depth of the tunnel is, the greater the influence on the stability of the tunnel is. At the same time, it is found that, with the increase of water injection, the cumulative settlement of each monitoring point decreases obviously, while the surrounding rock pressure of the monitoring points around the surrounding rock increases evenly with the increase of the advance bolting support. It can be seen that it is feasible to use the advance anchor bolt to pre-support it. (3) based on the project, the tunnel opening model is established based on the FLAC3D software, and the surrounding rock is softened by presetting the initial pore water pressure of four groups of surrounding rocks at 6.74 m below the arch roof. The influence of softening of surrounding rock on the retaining structure of granite residual soil tunnel is discussed based on the monitoring data of arch roof in the field. The results show that the softening of surrounding rock is very disadvantageous to the excavation of tunnel, so it should be dealt with in time before the tunnel is excavated.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U455.7

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