井筒冻结法施工的力学及数值模拟分析

发布时间：2018-11-19 10:26

【摘要】：立井井筒工程是矿井建设主要连锁工程项目之一,是整个矿井建设的咽喉,其设计和施工质量优劣直接关系到矿井建设成败和生产期的正常使用。本文以可可盖矿井立井井筒冻结法施工为背景,对立井井筒力学模型进行弹塑性力学分析;分析冻结前后岩土体力学性质变化;通过F L A C3 D数值模拟软件,采用工程方法折减力学参数,通过数值模拟分析不同冻结孔数量情况下开挖立井井筒井壁变形量及井筒围岩径向应力变化。综合井筒变形量及立井井筒冻结孔施工费用确定冻结孔数量。本文主要工作如下:1)基于弹性力学基本假设,将井筒受力问题简化,分析基于弹性假设井筒围岩受力及位移特点。分析不同冻结厚度条件下井筒围岩应力位移变化趋势,为后文数值模拟分析奠定理论基础。2)通过对井筒附近岩土体进行钻探,获取矿井岩土体水文地质条件资料。其主要探测工作包括:通过钻取岩样,对矿区岩层岩性进行分析;获取不同深度地层温度,分析地层温度随地层深度的变化趋势;通过探测孔探测地层含水情况,采用水平狭长廊道法概算井筒涌水量,为确定冻结法施工法提供依据。3)通过钻取岩样进行相关力学实验,测得各地层岩样冻结前后力学参数,其主要参数包括:抗压强度、抗拉强度、内聚力、内摩擦角和密度等。通过工程处理,将获得岩石力学参数转化为适用于数值模拟实验的力学参数,为后文数值模拟提供参数。4)采用工程折减后的力学参数,计算不同冻结孔条件下冻结厚度变化趋势,建立不同冻结孔数值实验模型,通过数值模拟计算不同冻结厚度条件下井壁偏移量。综合井筒井壁最大偏移量及冻结孔施工费用确定冻结孔数量。5)通过F L A C3 D数值模拟软件进行不同开挖深度下,在含水条件下,井筒井壁的孔压,通过分析,验证采用冻结法施工能有效地防水,降低井壁孔压。
[Abstract]:Vertical shaft engineering is one of the main chain projects of mine construction and the throat of the whole mine construction. The quality of design and construction is directly related to the success or failure of mine construction and the normal use of production period. In this paper, based on the construction of the shaft freezing method in the Cococo cap mine, the elastoplastic mechanics analysis of the opposite shaft mechanics model is carried out, and the changes of the geo-soil physical properties before and after freezing are analyzed. By means of F L A C 3D numerical simulation software, the mechanical parameters are reduced by engineering method. The deformation of shaft wall and the radial stress change of surrounding rock of shaft are analyzed by numerical simulation under the condition of different number of freezing holes. The number of freezing holes is determined by synthesizing the deformation of shaft and the construction cost of freezing hole in vertical shaft. The main work of this paper is as follows: 1) based on the basic assumption of elastic mechanics, the stress problem of wellbore is simplified, and the characteristics of surrounding rock force and displacement based on elastic assumption are analyzed. The variation trend of stress and displacement in surrounding rock of shaft under different freezing thickness is analyzed, which lays a theoretical foundation for numerical simulation analysis. 2) the hydrogeological condition data of rock and soil are obtained by drilling rock and soil around wellbore. Its main exploration work includes: through drilling rock samples, the lithology of mining area is analyzed, the formation temperature of different depth is obtained, and the variation trend of formation temperature is analyzed. The formation water content is detected by detecting holes, and the horizontal narrow corridor method is used to estimate the wellbore water inflow, which provides the basis for determining the freezing construction method. 3) relevant mechanical experiments are carried out by drilling rock samples. The mechanical parameters of rock samples before and after freezing are measured. The main parameters include compressive strength, tensile strength, cohesion force, friction angle and density. Through engineering treatment, the obtained rock mechanics parameters are transformed into mechanical parameters suitable for numerical simulation experiments, which provide parameters for later numerical simulation. 4) the mechanical parameters after engineering reduction are adopted. The variation trend of freezing thickness under different freezing hole conditions is calculated, and the numerical experimental model of different freezing hole is established, and the sidewall migration under different freezing thickness conditions is calculated by numerical simulation. Combined with the maximum deviation of wellbore and the cost of freezing hole construction, the number of freezing hole is determined. 5) under different excavation depth, under the condition of water cut, the pore pressure of shaft wall is analyzed by F L A C 3D numerical simulation software. It is proved that freezing method can effectively prevent water and reduce hole pressure.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD262

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