基于强夯振动的尾矿坝模型试验研究

发布时间：2018-02-22 20:19

本文关键词： 模型试验数值模拟振动速度和加速度位移液化　出处：《首都经济贸易大学》2015年硕士论文　论文类型：学位论文

【摘要】：尾矿库实际运行过程中,周边采场的爆破振动会对其造成不利影响。以炸药为振源的模型试验在现实中难以实现。论文用强夯振动作为振源,模拟振动对尾矿坝的影响。试验中振动速度和加速度等监测指标是易获得的,但是裂隙、垮塌、液化等宏观破坏现象易观察但却不易监测到真实有效数据。因此论文通过室内、外模型试验和有限元模拟计算,研究振动作用下尾矿坝振动速度、加速度与宏观破坏的相关关系。论文首先进行室内振动台试验,采用控制变量的方法为室外模型试验筛选出对尾矿坝稳定性产生影响的有效变量,从而确定合理的振动强度和尾矿砂湿度等试验参数;在振动台试验的基础上,建立小型的尾矿库室外试验模型,并以强夯振动为振源开展室外振动试验。监测和分析尾矿砂在强夯振动作用下发生稳定性破坏的条件和规律。根据试验获取的材料参数以及振动数据,采用Geo-Studio岩土工程数值仿真软件建立尾矿库数值模型,模拟尾矿坝发生失稳破坏的条件,验证室外试验和数值模拟的结果吻合度,并将室外模型试验结果与数值计算结果进行对比分析。论文得出了强夯振动作用下尾矿砂的液化和相对位移变化规律,并进一步了探究振动作用下尾矿砂发生变形、液化的宏观破坏现象与振动强度、砂体孔隙水压力变化之间的相关关系:(1)尾矿砂含水率存在一个最优范围,使得砂体稳定性达到最佳;(2)适当提高尾矿砂含水率对于增强砂体的稳定性和抗震性是有益的,砂体承受的垂直向振动加速度和瞬时相对位移明显降低,垂直向振动加速度和瞬时相对位移随强夯振动强度增加而增大的趋势减缓。因此浸润线控制对于尾矿库是至关重要的;(3)对于处于半固结或非固结状态非连续介质的松散砂体,适当的强夯振动会加速砂体沉积、排水,有利于松散砂体的密实、固结。但过高强度的强夯振动会对尾矿砂的稳定性造成不利影响;(4)强夯振动作用下,当尾矿砂孔隙水压力超过3.09k Pa时,尾矿砂体即可能发生液化;(5)模型含水率低于13%时,尾矿砂瞬时相对位移峰值与垂直向振动加速度的关系可以表示为:Y =-0.016 +;模型含水率高于13%时,尾矿砂瞬时相对位移峰值与垂直向振动加速度的关系可以表示为:Y=0.011+26.932()。通过强夯振动作用下的尾矿坝安全稳定性研究,获得了振动作用下尾矿坝失稳破坏规律,为政府部门开展尾矿库安全生产监督管理工作以及矿山生产企业安全生产具有指导意义。
[Abstract]:In the actual operation of tailings reservoir, the blasting vibration of the surrounding stope will have a negative effect on it. The model test with explosive as the vibration source is difficult to realize in reality. The dynamic compaction vibration is used as the vibration source in this paper. The effect of simulated vibration on tailings dam. The vibration velocity and acceleration are easy to obtain, but the macroscopic damage phenomena such as crack, collapse and liquefaction are easy to observe but not easy to monitor the real and effective data. The relationship between vibration velocity, acceleration and macroscopic failure of tailings dam under vibration is studied by external model test and finite element simulation. The method of controlling variables is used to screen out the effective variables that affect the stability of tailings dam for outdoor model test, so as to determine reasonable test parameters, such as vibration intensity and moisture of tailings, etc. On the basis of shaking table test, The outdoor test model of small tailings reservoir was established. Using dynamic compaction vibration as vibration source, outdoor vibration tests are carried out. Conditions and rules of stability failure of tailings under dynamic compaction vibration are monitored and analyzed. The numerical model of tailings dam is established by using Geo-Studio geotechnical engineering numerical simulation software, and the condition of instability and failure of tailings dam is simulated, and the results of outdoor test and numerical simulation are verified. The results of outdoor model test and numerical calculation are compared and analyzed. The liquefaction and relative displacement of tailings under dynamic compaction vibration are obtained, and the deformation of tailings under vibration is further explored. The relationship between macroscopic failure phenomenon of liquefaction and vibration strength, pore water pressure variation of sand body has an optimal range of water content of tailings. It is beneficial to enhance the stability and seismic resistance of the sand body by properly increasing the moisture content of the tailings. The vertical vibration acceleration and the instantaneous relative displacement of the sand body are obviously reduced. The vertical vibration acceleration and instantaneous relative displacement decrease with the increase of dynamic compaction vibration strength. Therefore, the soakage line control is very important for tailings reservoir. Proper dynamic compaction vibration will accelerate the deposition and drainage of sand body, which is beneficial to the compaction and consolidation of loose sand body. However, the high intensity dynamic compaction vibration will adversely affect the stability of tailings under the action of dynamic compaction vibration. When the pore water pressure of tailings exceeds 3.09 KPA and the water content of tailings is lower than 13, the relationship between the peak relative displacement of tailings and the vertical vibration acceleration can be expressed as: 1 / Y ~ (-0.016). When the water content of the model is higher than 13, the relation between the peak relative displacement of tailings and the vertical vibration acceleration can be expressed as: (1) Y 0.011 26.932. The safety and stability of tailings dam under dynamic compaction are studied. The unstable failure law of tailings dam under vibration is obtained, which is of guiding significance for government departments to carry out the work of safety production supervision and management of tailings reservoir and the safety production of mine production enterprises.
【学位授予单位】：首都经济贸易大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD926.4

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