基于数值模拟和模型试验的尾矿库地震动力响应特征研究

发布时间：2018-03-15 17:46

本文选题：岩土工程　切入点：数值模拟　出处：《昆明理工大学》2015年博士论文　论文类型：学位论文

【摘要】：近年来,不断加剧的矿业开发活动造成尾矿库数量快速增长,由于疏忽管理和维护,部分尾矿库存在安全隐患。国内外的尾矿库灾难不仅造成了重大人员伤亡和财产损失,同时也给库区下游带来了沉重的环境灾难。地震是诱发尾矿库事故的重要原因之一,对地震作用下尾矿库稳定性的研究具有重要意义。既有的研究主要关注于采用不同分析方法,计算不同条件下的尾矿坝静力和动力稳定性安全系数,对尾矿库动力响应规律的研究还不系统。因此,本文以个旧象冲尾矿库为研究对象,采用数值模拟和模型试验相结合的方法,系统的研究了尾矿库的地震动力响应特征。论文完成的主要工作和取得的研究成果如下：1、基于库区地表水文工程地质资料,通过分析岩层产状、泉点及地表径流特征,对场区建库的适宜性进行评价,从而提出了一种基于地质调查资料实现对场地评价的工程地质分析方法。分析结果表明：(1)冲沟呈等间距发育表明岩层抗侵蚀能力具有“均质各向同性”特征,区内存在控制性断裂构造的可能性较小。(2)岩性分布规律表明库区岩层是一套完整的沉积序列,区内绝大多数岩层北倾,产出状态较为稳定。(3)泉点具有数量多、密度大、流量小、空间分布随机的显著特征,冲沟流量大小与监测点上方汇水面积以及松散堆积物厚度正相关,表明库区地下水主要为孔隙水。(4)岩层的完整性和隔水性有利于尾矿库的建设和运营安全。2、利用场地动力学参数与深度的关系对场地地层进行概化,实现了大型复杂场地动力计算的简化数值模拟。基于数值模拟,首先研究了尾矿库静力位移场和应力场特征,并探讨了尾矿介质参数和筑坝工艺对尾矿库静力稳定性的影响,研究得出以下结论：(1)自重条件下尾矿库变形以沉降为主,堆积坝坝顶变形最为显著,尾矿坝具有沿某圆弧滑动面向下游失稳的趋势。(2)地基岩层应力分布呈近似水平层状,堆积坝坝顶存在拉应力区。(3)尾矿介质参数变化对尾矿库应力场和位移场分布特征没有明显影响,但是参数改变会引起位移和应力大小的变化。(4)静位移与尾矿弹性模量负相关,分级尾矿筑坝有利于坝体稳定性。3、基于数值模拟,系统的研究了地震作用下尾矿库的位移、应力及加速度特征,探讨了不同尾矿参数对尾矿库动力响应的影响。主要结论如下：(1)动位移随时步不断变化并且无明显规律,尾矿坝向临空面变形趋势明显。(2)动位移与尾矿弹性模量负相关,尾矿库纵向地震动力响应更为敏感。(3)从不同时步尾矿库最大位移值方向、大小及Y向永久位移大小上看,分级尾矿筑坝有利于坝体的稳定性。(4)动应力以压应力为主,拉应力主要存在于库区边缘和库内分水岭山脊等尾矿堆积厚度比较小的区域；尾矿介质参数和筑坝工艺与尾矿库的主应力和剪应力分布特征没有明显的相关性。(5)动力响应存在“介质突变效应”,尾矿库中部区域放大水平低于两侧库岸和库尾,尾矿和地基岩层参数差别越大,“介质突变效应”越显著。(6)动力响应具有临空放大效应,在堆积坝下游1/2坡高处动力放大水平较高,说明尾矿坝具有和边坡类似的动力响应特征。(7)动力响应存在“介质刚度效应”,随着尾矿弹性模量的增大,加速度放大水平提高。(8)动力响应存在“高程效应”,随高程的增加,响应水平提高,但由于多效应叠加,放大系数与高程并不严格正相关。4、构建涵盖场地、周围山体的大型尾矿库物理模型,依托大型振动台进行了尾矿库地震动力响应模型试验研究,结论如下：(1)尾矿库对输入地震波波形类别响应迟钝,但对地震波加速度峰值响应敏感,存在“加速度峰值”效应；相同地震波,输入峰值加速度越低,放大水平越高。(2)动力响应存在“介质刚度效应”,随着尾矿含水率的提高,监测点峰值位移及其平均值会提高,而加速度放大系数会降低；即介质越“软”,放大程度越低。(3)动力响应存在“介质突变效应”,当堆积坝介质刚度较低时,尾矿库与山体或模型边界接触部位放大水平较高,该效应会随着介质刚度降低被放大。(4)动力响应存在“高程效应”,放大水平与高程正相关,但由于多效应叠加的影响,堆积坝坝顶并不是地震放大水平最高的区域。5、通过对比数值模拟和模型试验的结果,对地震作用下尾矿库动力响应的一般规律进行了总结；利用剪切振动梁模型和能量守恒原理对尾矿库地震动力响应特征的力学机理进行了初步讨论,数值模拟和模型试验结果表现出较好的一致性。研究成果对尾矿库抗震设计和抗震措施研究以及揭示大型构筑物的地震动力响应规律具有重要意义。
[Abstract]:In recent years, mining activity continued to increase due to the rapid growth in the number of tailings, due to the negligence of management and maintenance, part of the tailings safety hazards. The domestic and foreign tailings disaster not only caused great casualties and property losses, and brought a heavy environmental disaster but also to the downstream region. The earthquake is one of the important causes of tailings Library of accidents, it is important to study the stability of tailings dam under earthquake. The existing research mainly focus on using different analytical methods, calculated under different conditions of static and dynamic stability of tailings dam safety coefficient, study on the dynamic responses of the tailings is not the system. Therefore, based on the old tailings as Chong library as the research object, using the method of numerical simulation and model experiment of combining the systematic study of the characteristics of seismic response of the tailings. The main work of this dissertation And the results are as follows: 1. The reservoir surface hydrological engineering geological data based on, through the analysis of terrane, springs and runoff characteristics, to assess the suitability of the construction area, and puts forward an analysis method based on the evaluation of site engineering geology of the geological survey data. The analysis results show that: (1) the gullies are equidistant development indicates that the anti erosion ability of "isotropic" feature, there is little possibility to control the fracture structure in the area. (2) showed that the distribution of reservoir rock lithology is a complete sedimentary sequence, in the vast majority of strata leans to the north, (output state is more stable. 3) spring has the quantity, density, flow rate, distribution characteristics of random space, gully flow and monitoring points above the catchment area and the thickness of loose deposits show that the groundwater mainly positive correlation Pore water. (4) integrity of rock and water is beneficial to the construction and operation safety of.2 tailings, the generalization of the stratum relationship using parameters and depth field dynamics, the simplified numerical calculation of large and complex dynamic simulation. Based on numerical simulation, firstly studies the static displacement of tailings field and stress field characteristics, and discusses the influence of medium parameters and process of tailings dam of tailings static stability, the research draws the following conclusions: (1) the weight of tailings under the condition of deformation dominated by subsidence and deformation of dam crest is the most significant accumulation of tailings dam has a circular sliding along the downstream for instability of the trend. (2) the foundation rock stress distribution is approximately horizontal layered, dam crest is the tensile stress zone. (3) the change of medium parameters on tailings tailings should not significantly affect the stress field and displacement field distribution, but the parameters change Will cause the change of stress and displacement size. (4) negative static displacement and elastic modulus of tailings, grade of tailing dam is conducive to the stability of the dam.3, based on numerical simulation, the system of tailings dam displacement under earthquake, stress and acceleration characteristics, discusses the influence of different parameters on the dynamic response of the tailings tailings the main conclusions are as follows: (1) the displacement at any time step change and no obvious rule, the tailings dam toward surface deformation trend is obvious. (2) the dynamic displacement and elastic modulus of the tailings tailings are negatively related to longitudinal seismic response is more sensitive. (3) and the maximum displacement of the tailings never step value direction. The size and Y to permanent displacement size and grade of tailing dam stability for dam. (4) the dynamic stress in the compressive stress, tensile stress mainly exists in the reservoir area and pool edge ridge tail ore thickness is relatively small Regional; tailings medium parameter and tailings dam construction and the principal stress and shear stress have no obvious correlation between the distribution characteristics. (5) the dynamic response of the existence of "medium mutation effect", the tailings level is lower than the central region on both sides of the bank and the amplified library, tailings and bedrock layer parameters to the greater difference, "the medium effect is more significant. The mutation (6) dynamic response has a free amplification effect, in the downstream of the 1/2 dam slope height dynamic amplification level is higher, and that of tailings dam has a similar slope dynamic response characteristics. (7) the dynamic response of" medium stiffness effect ", with the increase of tailings and the elastic modulus of horizontal acceleration amplification to improve the dynamic response. (8)" Gao Cheng effect ", with Gao Cheng's increased response level, but due to effect of superposition, amplification and Gao Cheng are not strictly positive correlation.4, build a covered field, the large tail of the surrounding hills The ore reservoir physical model, based on the large vibration of tailings dam seismic dynamic response test, the model results are as follows: (1) slow response to the input seismic wave tailings category, but sensitive to seismic peak acceleration, the existence of "acceleration" effect; the same seismic waves, the lower the input peak acceleration, amplification the higher the level. (2) the dynamic response of "medium stiffness effect", with the increase of moisture content of tailings, the peak displacement of monitoring points and its average value will increase, and the acceleration amplification coefficient will decrease; the medium is "soft", the lower the degree of amplification. (3) the dynamic response of "medium mutation effect" when the dam, medium stiffness is low, the tailings and mountain or boundary contact site amplification level is higher, the effect will be amplified with medium stiffness decreased. (4) the dynamic response of the existence of "altitude effect", the level of amplification Positive correlation with elevation, but due to the influence of multi effect, and the.5 is not the accumulation of dam crest seismic amplification of the highest level, through the comparison of the numerical simulation and model test results, the general regularity of dynamic response of tailings under earthquake are summarized; the shear vibration of the beam model and the principle of energy conservation mechanism of tailings reservoir seismic response characteristics are discussed. The numerical simulation and model test results well. The research results have important significance to the design and study of seismic and aseismic measures of tailings to reveal the laws of seismic dynamic response of large structures.

【学位授予单位】：昆明理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TD926.4;TD32

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