含水率对昔格达地层隧道围岩稳定性影响及控制技术研究

发布时间：2019-07-04 14:03

【摘要】：在四川攀西地区特有的“昔格达”地层多属于粉沙质泥岩,强风化岩石,遇水即会崩解溶化成泥浆状态,灰褐色的泥质粉砂岩中夹有钙质粉砂岩,强度风化,极为松软,围岩不能自稳,抗压强度极低,为极不稳定的泥砂岩。昔格达地层交通建设的实践表明,在建设过程中会诱发规模较大的滑坡、崩塌、渗水、软化、流变、隧道围岩变形坍塌破坏等各类灾害。目前穿越昔格达地区面临的工程地质问题日益突出,很多方面技术不成熟,直接影响铁路和公路建设的正常进行,不能满足当前交通建设快速发展的需要。本文以新建成昆铁路米易至攀枝花段扩能工程为工程依托,采用现场调研及查阅资料、理论分析、数值模拟、室内土工实验等手段结合的方法进行研究,针对昔格达地层遇水崩解软化的的特殊工程性质,通过室内土工试验研究了含水率对昔格达地层围岩物理力学性质的影响规律,并结合国内学者研究成果对5种昔格达地层土样的围岩进行了进一步的围岩分级。本文引入强度折减法作为昔格达地层隧道围岩稳定性的评价方法,以隧道特征点的位移是否突变作为隧道的失稳判据,结合数值模拟,研究了含水率对昔格达地层隧道围岩稳定性影响,给出了评价昔格达地层隧道围岩稳定性定量的评价方法。最后,对目前控制围岩稳定性的常用施工工法在昔格达地层中的适用性进行了分析,根据设计、施工单位反馈的信息,重点研究了结合锁脚锚杆的三台阶短台阶法和三台阶超短台阶法控制昔格达地层围岩稳定性的效果。
文内图片：
图片说明：图２－１昔格达地层浅灰色页岩遇水前后形态对比图逡逑
[Abstract]:Most of the "Xigda" strata in Panxi area of Sichuan Province belong to silty mudstone, and the strongly weathered rock dissolves and dissolves into mud state when water is encountered. Calcareous siltstone is sandwiched in the grayish-brown argillaceous siltstone, which is very soft, the surrounding rock can not stabilize itself, and the compressive strength is very low. The practice of traffic construction in Xigeda strata shows that large scale landslides, collapses, seepage, softened, Rheological, deformation and collapse of tunnel surrounding rock will be induced in the process of construction. At present, the engineering geological problems faced by Xigeda area are becoming more and more prominent, and the technology is not mature in many aspects, which directly affects the normal progress of railway and highway construction and can not meet the needs of the rapid development of current traffic construction. Based on the newly built capacity expansion project of Miyi to Panzhihua section of Kunming Railway, this paper studies the special engineering properties of Xigeda formation when water collapses and softens by means of field investigation and consulting data, theoretical analysis, numerical simulation, indoor geotechnical experiment and so on, and studies the influence of moisture content on the physical and mechanical properties of Xigeda formation surrounding rock through indoor geotechnical test. Combined with the research results of domestic scholars, the surrounding rock of five kinds of Xigeda formation soil samples was further classified. In this paper, the strength reduction method is introduced as the evaluation method of surrounding rock stability of Xigeda strata tunnel, and whether the displacement of tunnel characteristic points is abrupt or not is taken as the instability criterion of tunnel. Combined with numerical simulation, the influence of water content on the stability of surrounding rock of Xigeda formation tunnel is studied, and the quantitative evaluation method of surrounding rock stability of Xigeda strata tunnel is given. Finally, the applicability of the common construction methods to control the stability of surrounding rock in Xigeda strata is analyzed. According to the information of design and construction unit feedback, the effect of three-step short step method and three-step ultra-short step method combined with anchor rod to control the stability of surrounding rock of Xigeda formation is studied.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.49

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