爆破动载作用下出矿巷道稳定性研究

发布时间：2018-04-13 06:45

本文选题：爆破震动 + 稳定性　；参考：《江西理工大学》2016年硕士论文

【摘要】：千家坪钒矿采用水平扇形深孔阶段矿房法回采矿石,由于采场爆破施工具有装药量大、次数多、井下空间有限等特点,使爆破震动对邻近巷道围岩造成损伤显现的愈发明显。尤其是现场部分区域边墙已经出现裂缝,顶板已有小块岩石脱落。考虑到掌握爆破震动对巷道围岩的破坏机理,即可通过采取相应控爆措施,达到维护采场稳定的目的。因此,本文结合矿山生产实际,以采场实测震动数据为依据,通过理论分析、回归分析、FLAC~(3D)数值计算等手段,分析深孔爆破震动对邻近巷道围岩稳定性造成的影响,并结合现场生产实际,提出相应的控爆措施。本文主要研究成果如下:(1)首先,通过对生产工艺流程、爆破参数设计与出矿巷道破坏现状的调研,设计并实施+745中段采场爆破震动测试,记录深孔爆破时出矿巷道底板处的震动速度、持续时间、主震频率等参数。其次,通过对实测数据进行回归分析,得到爆破震动波在该区域的衰减规律,为采场爆破参数优化提供依据。最后,采用HHT方法对采场某一实测信号分析,发现其能量主要集中于50Hz以内,且大多分布于10Hz~20Hz的低频带,并与地下建筑物的自振频率接近,极易引起共振,造成事故,应额外注意;同时,也发现信号瞬时能量的分布主要集中于0.2s~0.4s时段,且微差效果体现不明显,建议重新确定最大单段起爆药量和雷管段别,以达到最好降震效果。(2)动载作用下出矿巷道稳定性的数值模拟研究。选取+795中段出矿巷道作为研究对象,根据工程实际建立数值计算模型,以实测垂向震动速度作为动荷载输入波形,分别计算自重状态下与动荷载状态下巷道围岩的应力场、位移场、塑性区与速度场的变化规律。结果显示,虽然爆破震动对巷道围岩(未支护)的位移、应力、塑性区造成的影响较小,但巷道底部较其他区域变化更明显,说明爆破震动对巷道破坏比较有限,且主要集中于底板与墙脚处;通过与锚喷支护后的巷道对比,发现锚喷支护可以进一步降低爆破震动对巷道造成的影响;通过监测巷道四周(除底板)质点的应力场、位移场、速度场随时间的变化规律,发现应力、速度随时间的变化曲线与动荷载输入波形变化大体一致,同时,也发现巷道墙脚处的应力极值变化最大、速度极值变化最大,位移(同一时刻)变化最大,说明爆破震动(仅爆源位于正下方时)对巷道底部影响最大。(3)出矿巷道稳定性监测。通过对爆破作业前后巷道变形的监测,发现其变形处于正常情况,与数值模拟结果比较接近。但在实际中,多次累积爆破后,作业点上方巷道仍会出现一定程度破坏,且在今后频繁的回采作业后,巷道围岩的损伤会进一步累积,进而超过安全阈值,最终导致巷道失稳。因此,巷道掘进后,应该及时对危险区域采取支护措施,并调整爆破作业参数,降低爆破震动对巷道的破坏。
[Abstract]:In Qianjiaping Vanadium Mine, the horizontal fan deep hole stage is used for mining ore. Because the stope blasting construction has the characteristics of large charge, many times and limited underground space, the damage caused by blasting vibration to the surrounding rock of adjacent roadway becomes more and more obvious.In particular, cracks have appeared in the side walls of some areas, and small rocks have fallen off the roof.Considering the failure mechanism of blasting vibration on the surrounding rock of roadway, the aim of maintaining stope stability can be achieved by adopting corresponding blasting control measures.Therefore, based on the actual mine production, based on the measured vibration data of stope, by means of theoretical analysis and regression analysis, this paper analyzes the influence of deep-hole blasting vibration on the stability of surrounding rock in adjacent roadways by means of regression analysis and numerical calculation.Combined with the field production practice, the corresponding explosion control measures are put forward.The main research results of this paper are as follows: firstly, through the investigation of production process, blasting parameter design and roadway damage, the blasting vibration test of 745 middle stope is designed and carried out.The vibration velocity, duration, main shock frequency and so on were recorded during deep hole blasting.Secondly, through regression analysis of measured data, the attenuation law of blasting vibration wave in this area is obtained, which provides the basis for optimization of blasting parameters in stope.Finally, the HHT method is used to analyze a measured signal in the stope. It is found that the energy is mainly concentrated in the 50Hz, and most of the energy is distributed in the low frequency band of the 10Hz~20Hz, which is close to the natural vibration frequency of the underground building, so it is easy to cause resonance and cause accidents.At the same time, it is also found that the distribution of instantaneous energy of the signal is mainly concentrated in the 0.2s~0.4s period, and the effect of slight difference is not obvious. It is suggested that the maximum amount of detonator and detonator section should be redetermined.Numerical simulation study on the stability of roadway under the action of dynamic load is carried out in order to achieve the best effect of earthquake reduction.In this paper, a numerical model is established according to the engineering practice, and the measured vertical vibration velocity is taken as the input waveform of dynamic load to calculate the stress field of roadway surrounding rock under gravity state and dynamic load state, respectively.The variation of displacement field, plastic zone and velocity field.The results show that although blasting vibration has little effect on the displacement, stress and plastic zone of surrounding rock of roadway, the change of roadway bottom is more obvious than that of other regions, which indicates that blasting vibration has limited damage to roadway.By comparing with the roadway after bolting and shotcreting, it is found that the bolting and shotcreting can further reduce the impact of blasting vibration on the roadway, and by monitoring the stress field and displacement field around the roadway (except floor),The variation law of velocity field with time shows that the variation curve of stress and velocity with time is approximately the same as that of dynamic load input waveform. At the same time, it is also found that the maximum change of stress extreme value and velocity extreme value are found at the base of roadway wall.The change of displacement (at the same time) is the biggest, which indicates that blasting vibration (only when the blasting source is directly below) has the greatest influence on the roadway bottom.Through monitoring the tunnel deformation before and after blasting, it is found that the deformation is in normal condition, which is close to the numerical simulation results.However, in practice, after multiple cumulative blasting, the roadway above the working point will still be destroyed to a certain extent, and after frequent mining in the future, the damage of surrounding rock of roadway will accumulate further, and then exceed the safety threshold, which will eventually lead to the roadway instability.Therefore, after tunneling, support measures should be taken in time to the dangerous area, and the blasting operation parameters should be adjusted to reduce the damage caused by blasting vibration to the roadway.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD322.4

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