【作者】 江学良；

【导师】 曹平；

【作者基本信息】 中南大学 ， 岩土工程， 2008， 博士

【摘要】 地下洞室包括各类天然形成的地下空区（溶洞等）、矿山生产过程中形成的地下采空区以及各类人工开挖形成的洞室（如人防洞、隧道等）。地下洞室与边坡的相互影响问题是随着工程建设的开展而出现的。根据地下洞室与边坡存在的先后顺序将地下洞室与边坡的关系分为两种情况,第一种情况是地下洞室先于边坡存在,如地下开采转为露天开采条件下矿山的地下采空区与露天开挖的边坡;另一种情况是边坡先于地下洞室存在,如山区隧道开挖形成的洞口边坡与隧道。地下洞室与边坡的相互影响问题一般可以分为两个方面来研究:一方面是地下洞室的存在对边坡稳定的影响;另一方面是边坡施工对地下洞室稳定性的影响。另外,根据地下洞室与边坡的相对空间位置还会带来另外一个十分重要的问题,即地下洞室顶板的安全厚度问题。顶板的安全厚度关系到地下洞室的安全与正常运营,甚至关系边坡的稳定。本文结合湖南省自然科学基金资助项目“GFRP锚杆加固岩质边坡基本理论与设计方法研究”（07JJ6084）与高等学校博士点学科专项基金项目“复杂岩体边坡最危险滑动面的滑移线分条自动搜索研究”（20060533071）以及贵州宏福实业开发有限总公司“瓮福磷矿穿岩洞矿段地下转露天开采中地下采空区对露天开采的影响研究”等研究课题,对地下洞室与边坡之间的相互影响以及顶板安全厚度进行了深入的研究。主要研究内容与结论如下:建立了边坡下伏地下岩石洞室深埋与浅埋的计算模型,应用弹性力学理论与相同映射函数的复变函数解法推导了边坡下伏浅埋圆形洞室的应力解析解,将深埋洞室视为一个双向受压无限板板孔应力集中问题,得到了边坡下伏深埋圆形洞室的应力解析解,对于复杂形状洞室,采用Christoffel-Schwarz积分确定映射函数或采用近似方法和数值方法来研究。采取弹塑性有限元与强度折减方法,利用自编的有限元程序对瓮福磷矿穿岩洞矿段地下采空区与露天边坡的相互影响进行了研究,模拟露天边坡开挖过程对边坡与地下采空区的影响,得到了各部开挖过程中边坡与采空区的应力、应变与塑性区分布以及边坡的安全系数。对工程上常用来估算地下洞室顶板安全厚度的简支梁与固支梁模型进行了改进,应用结构稳定理论,考虑地下洞室水平应力对安全顶板厚度的影响,分别建立集中力与均布荷载作用下改进的简支梁与固支梁模型。对改进的梁模型考虑岩石本构关系的影响,将岩石视为理想弹塑性材料,建立了改进梁模型的广义弯矩-曲率-轴力关系,并采取假设挠曲线的近似解法得到了最大承载力的广义弯矩-轴力-侧向均布荷载的相关方程。运用裂隙张量理论,将岩体中的裂隙看作初始损伤,对含随机分布裂隙的顶板岩体进行了分析,推求了裂隙岩体的等效变形模量和等效泊松比,研究裂隙密度对地下洞室顶板厚度的影响。应用突变理论建立了地下球形洞室与地下巷道式洞室顶板的突变模型,得到地下洞室顶板失稳破坏的必要条件与充分条件。经过分析可知,地下洞室顶板安全厚度与岩石弹性模量、泊松比、洞室跨度、自重以及板顶荷载与板端水平应力有关。将顶板上车辆荷载视为简谐荷载,研究在车辆简谐荷载作用下顶板的动力响应,得到了在匀速移动的车辆简谐荷载下,考虑基本振型时,共振发生在ω₁=Q_p,动力放大因子将取决于车辆移动的速度。在一般阻尼情况下,动力放大因子取决于阻尼比ξ₁的大小,匀速移动车辆荷载作用下动力响应只有固定于跨中的车辆荷载作用下的动力响应的一半。建立了车队荷载作用下,地下洞室顶板失稳的突变理论模型,得到了顶板失稳破坏的充要条件。将地下洞室顶板视为单向厚板或矩形厚板,在车辆荷载作用下进行了动力学分析,分析了不同边界条件的影响,得到了在车辆振动荷载作用下顶板的动力放大系数。采用FLAC^3D如软件与强度折减理论对地下采空区的顶板厚度与稳定性进行了分析,并且研究了地下采空区的采高与跨度对顶板厚度的影响。针对瓮福磷矿穿岩洞矿段地下转露天开采中的地下采空区与露天边坡,采用SURPAC软件建立了地下采空区的三维地质模型,编制了模型与FLAC^3D的接口程序,将三维模型导入FLAC^3D如计算程序,在边坡与空区设置监测点,研究分析地下采空区与露天边坡之间的相互影响。本文立足于学科前沿,运用最新数学计算方法和手段,对地下洞室与边坡的相互影响进行了深入研究,具有较高的理论和应用价值。更多还原

【Abstract】 Underground cavern include the natural underground vacant areas （for example, karst cave）, underground mined area formed in the mine production progress and artificial cavern because of manual excavation （for example, air defense cave and tunnel）. The research of influence between underground cavern and slope appears along with the development of engineering construction. According to the formed sequence of the underground cavern and slope, the relationship of them can be divided into two conditions. The first condition is that the underground cavern had existed before the slope excavation, such as the mined underground area under the excavation slope in the case of underground mining converted to surface mining. The second condition is the slope had existed before the underground cavern formed, such as the tunnel excavation in mountainous areas. The research of interaction between the underground cavern and slope can be divided into two aspects. The one aspect is the influence of underground cavern on slope, the other aspect is the effect of slope excavation on underground cavern. In addition, the other important problem which is result from the relative tertiary location of underground cavern and slope is the safety roof thickness of underground cavern. The safety roof thickness relates to the safety and normal operation of underground cavern and even determines the stability of slope. In this paper, the author studied deeply the interact between the underground cavern and slope and the safety roof thickness, combining with the three projects: the project supported by HuNan provincial natural science foundation of China " （07JJ6084） , doctoral subject special fund of university in China （20060533071） and the project supported by HongFu company of GuiZhou province "the influence research of underground mined area on surface mining of WenFu phosphate mine". The main contents of the dissertation are summarized as follows:The calculation models were built which were applied to the analysis of deep-buried and shallow-buried rock cavern under the slope, the round shallow-buried cavern’s stress analytic solution was derived by elasticity theory and complex function method, the deep-buried cavern was regarded as a stress concentration problem of biaxial compression infinite plate pole and the analytic solution of stress was gotten. For complex shape rock cavern, the Christoffel-Schwarz integral, approximate method or numerical method were used to analyze the stress and strain.The interact between the underground mined area and the slope in WenFu phosphate mine was researched and analyzed by elasto-plastic finite element method of lowing material’s strength safety factor using my own two-dimensional FEM program, the effect of the underground mined area and the open pit slope was simulated in the slope excavation process and the stress ,the strain , the distribution of plastic zone and the safety factor of the underground area and the slope were gotten by analysis.The model of simply supported beam and the model of clamped-clamped beam which are often applied to estimate the safety roof thickness of the underground cavern were improved by considering the influence of horizontal stress of beam end on safety roof thickness, the improved beam models were built on the condition of concentrated force and uniform load acting on the beam by structural stability theory. The rock was looked on as perfectly elastic-plastic material and the relationship of the generalized moment-curvature-axial force was established and the equation of the generalized moment-axial force-lateral uniform load was built through the approximate solution method in which the beam deflection curve was assumed. For fractured rock mass, the fracture of rock was regarded as initial damage, the roof rock mass with random distribution fracture was researched, the equivalent deformation module and the poisson ratio of fracture rock mass were deduced and the effect of fracture density on the roof thickness was analyzed.The catastrophe models of underground spherical cavity and tunnel were established with catastrophe theory and the necessary and sufficient condition of roof failure was derived. The analysis shows that the underground cavern roof thickness is related to rock elastic modular, poisson ratio, cavern span, roof dead weight, the load acting on the roof and horizontal stress of roof end.The dynamic response of roof on which vehicle load act was researched regarding the vehicle load as harmonic load. The conclusions show the resonance happens whenω₁ = Q_p and the dynamic amplification factor depends on the vehicle velocity , the vibration response is larger while the driving velocity is slower when the vehicle drives on the roof with the same velocity only considering the model’s basic vibration type. On the condition of general damping, the dynamic amplification factor depends on damping ratio （ξ₁） and the dynamic response when the vehicle drive on the roof with the same velocity is only half dynamic response when the vehicle is fixed to the roof mid-span. The catastrophe theory model of roof failure was built when the vehicle platoon acts on the roof and the necessary and sufficient condition of the roof failure was derived. In order to analyze the influence of calculation model, the roof was looked on as unidirectionally or rectangular thick plate model and the roof dynamic response was calculated, the effect of different boundary conditions was analyzed and the dynamic amplification factor was gotten with the vehicle vibration load.The underground mined area’s roof safety thickness and its stability were analyzed by using FLAC^3D method and lowing material’s strength safety factor method, the influence of the underground cavern’s mining height and its span on the slope’s stability was calculated. Taking the underground mined area and surfacing slope in the WenFu mine for example, the 3D geological model of the underground mined area was established with SURPAC software, the interface program of the model to FLAC^3D was written and the displacement and stress monitoring points were set in the underground mined area and the slope, the interaction betweem the underground mined area and open pit slope was researched with introduced 3-D geological model into FLAC^3D calculation program.Stood at the front of science research, the interaction between underground cavern and the slope is studied in the author’s dissertation using newly numerical methods and means in the course of research work. It shows a high theoretical and practical value.更多还原