【作者】 朱杰；

【导师】 孙树林；

【作者基本信息】 河海大学 ， 地质工程， 2006， 硕士

【摘要】 在矿山开采,交通运输和水利水电等建设工程中,大量存在着节理岩体边坡,其稳定性对工程实施有至关重要的影响。节理岩体边坡的稳定性跟边坡中的不连续面的关系密切,如节理、裂隙、断层以及软弱夹层等,这些结构面纵横切割,使得岩体的性质与完整岩石大相径庭,因此,必须对节理岩体边坡的变形破坏机制和稳定性分析作深入的研究。 块体理论作为分析节理岩体边坡的重要方法,已经在工程界得到广泛的应用。随着研究的深入,其理论和方法也不断的发展和拓宽。本文在工程地质调查的基础上使用块体理论,并结合概率模型,正交敏感性分析,可靠度计算和数值模拟建立了节理岩体边坡稳定性分析的计算方法,并应用于南京北极阁风貌区岩体边坡的稳定评价,研究成果具有较大的理论和实用价值。本文的主要成果如下: (1)结合南京北极阁岩体边坡的具体工程情况,采用块体理论确定其开挖面上的关键块体,对于找出的关键块体计算其节理交切概率和裂隙锥不稳定参数,从而得到失稳概率P(B),用失稳概率评价关键块体的破坏可能性,确定较易失稳的关键块体即危险块体。 (2)利用正交试验设计,对于失稳概率较高的危险块体进行影响因素的敏感性分析,将不同因素的敏感性分级排列,对影响效果显著的因素给予重视。 (3)对确定的危险块体,采用蒙特卡罗法,全面考虑结构面几何参数和力学强度的随机性,计算不同大小块体的破坏概率,并拟合破坏概率与分界边长的函数关系。将节理迹长的分布用于分析块体的形成机率,计算不同大小块体的形成概率,得出块体形成概率的密度函数。对块体大小进行分区,计算不同区间的块体破坏概率和形成概率,得到联合概率分布,来评价不同区间块体的稳定性,从而确定最易产生破坏的块体区间,为工程设计提供依据。 (4)运用FLAC-3D模拟边坡开挖过程中的应力应变关系,讨论开挖卸载后软弱层和断层带形成的块体对边坡稳定的影响,从位移,应力场和系统不平衡力等方面来研究边坡的块体稳定性,充实了块体理论研究关键块体的不足,更全面的深入的对边坡稳定性进行分析和评价。更多还原

【Abstract】 In construction projects,such as mining engineering,communications and transport engineering,hydroelectricity and water conservancy engineering,rock mass slopes exist in bulk.The stability of them has an vital influence on project implementation,which is also hand in glove with discontinuity surface, for example,joints,fissure,fault and weak interbed etc.These discontinuity intersect vertically and horizontally ,which makes great difference in property between it and integrated rock.On that account,we should do deepgoing research on deformation failure mechanism and stability analysis for rock mass slopes.As a significant method for rock mass slope analysis,Block Theory has been used far and wide in engineering field.With embedded study,its theory and method has been broadened and developed continuously.On the basis of project geological investigation, the paper adopts Block Theory together with probability model,orthogonall sensitivity anslysis,reliability calculation of block and numerical simulation to establish computation method for stability analysis of rock mass slope.lt has been applied in the stability evaluation of rock mass slope of BeiJiGe scene zone in NanJing,the result of which contains great theory and practical value.The main achievement for this paper as follows:(1) Combined with concrete project situation of BeiJiGe rock mass slope,the paper makes use of Block Theory to determine the key block on excavation surface.and reckons the joint combination probability and the JP instability parameter for the key block,so the block failure likelihood P(B) is abtained.Then we could apply P(B) into accessing failure probability and decide which key block is the dangerous block(2) Orthogonal experiment design is used to analyze influential factor’s sensitivity for dangerous block,and array sensitivity of distinct factors gradedly.The project should pay more attension to the factor of obvious effect.(3) With regard to determined dangerous block,the paper makes use of Monte-Carlo method to calculate failure probability of block of different sizes, considering the random distribution of geometry parameters and mechanics intensity of block globally,and fit the function relationship between failure probability and dividing side length.After putting distribution of joint trace length forward to analyze the formation probability,we could reckon formation probability for block of different size,and achieve density function of formation probability.Block is subregionedaccording to size,and failure and formation probability in distinct region is calculated,so the association probability distribution is abtained to evaluation block stability of different region.Then the easy-failure block region is achieved to offer reference to project design.(4) The stress-strain relationship during slope excavation is simulated by FLAC-3D,and the affection for slope stability of the block formed by weak layer and fault is discussed after excavation.This paper does research on the block stability of slope in terms of displacement,stress field and systemic imbalance force,and enrichs the deficiency research on key block by Block Theory,and evaluates slope stability globally and deeply.更多还原