【作者】 岩小明；

【导师】 李夕兵； 陈祥云；

【作者基本信息】 中南大学 ， 资源与环境经济学， 2013， 博士

【摘要】 摘要：本文针对目前露天矿边坡开挖过程中力求达到安全性和经济性相统一的工程实践问题,开展了基于可靠度理论的露天矿边坡经济风险分析问题的研究。面对露天矿边坡工程存在不确定性和随机性的客观事实,在深入分析露天矿边坡自身特点的基础上,以可靠度理论为主线,构建了露天矿边坡经济风险分析的步骤和程序。文中对露天矿边坡的经济风险分析中的四个关键问题,即边坡破坏模式识别、边坡目标可靠度的确定、边坡随机变量概率分布的推断和可靠度计算方法的选择,有针对性的展开研究。并以城门山二期露天矿扩建工程南帮边坡作为工程实例,进行了以可靠度理论为基础的最佳边坡设计方案的优化。所取得主要结论和研究成果如下：(1)基于距离判别分析理论,并结合露天矿边坡失稳的特点,选取了岩石单轴抗压强度、结构面倾角、结构面与边坡面的位置关系、地下水条件、岩体结构类型、内聚力、内摩擦角、边坡高度、边坡角等9个因素作为判别露天矿边坡潜在破坏模式的指标,建立了露天矿边坡潜在破坏模式识别的距离判别分析模型。以21个典型露天矿边坡的信息作为学习样本进行训练,建立相应的判别函数进行识别,并以回代估计法对该模型进行检验。研究结果表明,经过学习后的模型误判率为0.05,具有较高的判别能力。将建立后的模型应用于大冶铁矿、南芬铁矿和城门山铜矿的露天矿边坡实例的失稳模式判别,为露天矿边坡潜在破坏模式识别提供了一种新方法。(2)按照工程可靠度统一标准的要求,充分考虑我国露天矿山开采技术的现状和发展趋势,并结合非煤露天矿边坡工程技术规范情况,确定了露天矿边坡服务年限和三个安全等级。在此基础上,综合整理了国内外有关露天矿边坡可接受的破坏概率,并参考现行的建筑、水利、公路、铁路、港口等5个领域的可靠度统一设计标准中关于目标可靠度制定情况,综合确定了露天矿总体边坡在Ⅰ级安全级别下第一类破坏(破坏前具有征兆性)的可接受风险概率为1×10一,对应的目标可靠指标为3.1,进一步给出了露天矿总体边坡可靠性分析的基本依据和标准。将该标准应用于城门山铜矿二期扩建工程露天矿边坡的可靠性分析,确定该露天矿总体边坡属于Ⅰ级安全级别下的第一类破坏,给出了可接受的风险概率。(3)针对露天矿边坡岩土参数容量是小样本的情况,提出了推断边坡抗剪强度参数概率模型的正态信息扩散法。考虑到一般情况下岩石抗剪强度参数样本量较小,以岩石单轴和三轴压缩试验数据为基本信息,根据排列组合理论构建小样本容量下的抗剪强度参数信息库。并利用稳健回归估计方法得到粘结力c和内摩擦角φ的样本数据。最后基于正态信息扩散原理,推断获得这两个强度参数的概率分布函数,并采用精度较高的K-S检验法进行检验。研究结果表明,基于正态信息扩散原理得到的抗剪强度参数的概率分布更加接近参数的实际分布规律,所得结果均优于传统拟合检验法。(4)针对露天矿边坡极限状态方程存在抗滑力以及滑动力两个连续随机变量和多个随机变量的不同情况,分别给出了基于信息扩散原理的边坡破坏概率计算公式。同时,以安全系数构造的极限状态方程为基础,推导了随机变量期望和标准差的信息扩散表达式,给出了露天矿边坡破坏概率和可靠度指标的计算方法。(5)以江西城门山铜矿二期扩建工程为工程背景,构造了其南帮露天矿边坡的经济风险分析模型。以具体矿岩的单轴和三轴压缩试验数据为基本信息,构建小样本容量下的抗剪强度参数信息库。并以简化Bishop分析法获得露天矿边坡的安全系数和最危险滑动面。在分析了露天矿边坡剥岩减少费用、破坏概率和潜在滑坡体体积随边坡角递增的变化规律基础上,得到了经济风险收益最大的最佳优化方案。更多还原

【Abstract】 ABSTRACT:In the excavation process of open-pit slope, the aim of engineering practice is to achieve an unity between security and economy. In order to solve this problem, the study on open-pit slope economic risk analysis based on reliability theory was conducted in this paper. In the face of objective fact that there are some uncertainty and randomness existed in open-pit slope project, based on the depth analysis of open pit slope characteristics, with reliability theory as the main line, the analysis steps and procedures of open-pit slope economic risk were constructed. Four key problems, including failure mode recognization of slope, slope target reliability determination, deduction of slope random variable probability distribution and selection of reliability calculation method, were studied pertinently. The main contents and conclusive results are as follows:(1) The identification of open-pit slope potential failure mode is one of the most basin works to study the unstability and failue of slope. Based on the theory of distance discriminant analysis and combined with the characteristics of open-pit slope instability, nine factors, including the uniaxial compressive strength of rock, structural plane angle, the position of structural plane slope plane, groundwater conditions, types of rock mass structure, cohesion, internal friction angle, slope height, slope angle, were selected to build a distance discriminant analysis model to identify the potential failure mode of open-pit slope. Linear discriminant fuctions were obtained through training of21sets information of typical open-pit slopes. The resubstitution method was used to varify the identification ability of this model. The research results show that, the misjudge rate of the model is0.05and the discriminant ability is higher. This model was applied to the instability mode discrimination of three open-pit slopes. This paper provided a new method to identify the potential failure mode for open pit slope.(2) According to the requirements of engineering reliability unified standard, and considering the current situation and development trend of China’s open pit mining technology, and combining with the slope engineering technical specifications of non-coal open-pit mine, the service life and three security levels of open-pit slope was determined. On this basis, the study of acceptance damage probability of open-pit slope at home and abroad were collected and analyzed, and the target reliability in five current reliability unified design standards, including building, hydraulic, highway, railway and port, were also referenced, the acceptance damage probability for the first failure model (with symptomatic before failure) of open-pit overall slope under I security level was determined as1×10-3and the corresponding index of target reliability is3.1. The basic standard and criterion of open pit mine slope reliability analysis was also given and was applied in the open-pit mine reliability design in second phase expansion project of Chengmenshan Copper Mine.(3) Based on normal information diffusion principle, a probability model deduction method of shear strength parameters with small sample size is presented in this paper. Considering the sample size of rock shear strength parameters is small in general, the testing data of rock uniaxial and triaxial compression were regarded as basic information, and information base of shear strength parameters with small size was constructed according to the permutation and combination theory. And the sample data of cohesive force c and internal friction angle φ were also obtained using robust regression estimation method. Finally, based on the normal information diffusion theory, the probability distribution functions of c and cp were deducted. K-S test method was used to compare the results of traditional fitting-test method and presented method. The results show that, the probability distribution of shear strength parameters based on normal information diffusion principle is more close to the actual probability distribution. Whether in terms of test value and the cumulative probability, the results of presented method are better than the traditional fitting-test method.(4) According to the different situation of open pit mine slope limit state equation has two continuous random variables:anti slide force and sliding force and multi-random variables, the computational formula of failure probability based on information diffusion principle was obtained. At the same time, the limit state equation is constructed based on the safety factor, information diffusion equations of random variable expectation and standard deviation were given. The calculation method of failure probability and reliability index of open-pit slope was also obtained.(5) The second phase expansion project of Chengmenshan Copper Mineas was considered as the engineering background, the economic risk analysis model of south open pit slope was constructed. The information base of shear strength parameters with small size was constructed by using the testing data of rock uniaxial and triaxial compression. The slope safety factor and the most dangerous sliding surface can be obtained by using the simplified Bishop method. With the increaseing of slope angle, the change rule of the reducing cost of stripping rock, failure probability and potential landslide volume were analyzed. At last, the best optimization solution of south open pit slope with the maximum economic risk benefit was obtained.更多还原