【作者】 汪海波；

【导师】 徐颖；

【作者基本信息】 安徽理工大学 ， 安全技术及工程， 2013， 博士

【摘要】 钻眼爆破法仍是目前煤矿井下巷道施工的主要破岩手段,随着煤炭开采规模的扩大,爆破施工作业时的起爆药量和引发的振动强度也增大,频繁的爆破振动对巷道围岩和支护结构的安全性产生了影响。多年来,国内外对爆破振动的传播规律、危害机制和控制对策等进行了大量的研究工作,取得了丰硕的成果,主要集中在地面工程爆破地震效应对周边临近建筑物的影响、隧道(包括公路、铁路和水工隧道)施工爆破地震效应对相邻隧道和周边围岩的影响以及大型基坑、地下厂房开挖爆破地震效应对围岩的损伤、露天矿山开采爆破振动等方面,而在爆破地震效应对巷道稳定性影响方面的研究很少。在查阅国内外相关研究资料的基础上,本文通过对不同条件下煤矿巷道掘进爆破和工作面过断层岩石深孔松动爆破施工时产生的振动进行测试和分析,并基于Matlab软件应用HHT变换和小波包变换,对煤矿井下爆破振动特性及其对巷道围岩、支护结构的影响等问题进行较为深入的研究。论文的主要研究工作及成果如下：从理论上分析了爆破能量的分布和爆破地震波的形成、传播规律以及影响因素。建立了炮孔不耦合装药爆破试验模型,对不同不耦合介质和不耦系数时模型不同位置处爆破应力波峰值压力和爆破振动速度进行了测试和分析,应力波峰值压力和地震波振速随不耦合系数的增大而减小,且水不耦合时二者的值大于空气不耦合时。根据不同现场爆破施工情况,对其爆破作业引发的振动进行了监测和分析,发现振动速度三个方向分量峰值中水平径向方向(巷道走向方向)最大,得到了相应的爆破振动合速度和各方向分量的衰减规律,分析了其与地面爆破时的差异；巷道掘进爆破时底板岩石的破碎是影响其传播规律的主要原因；振动速度的大小与爆破时的炮孔深度、单孔药量和岩性直接相关。采用HHT变换和小波包变换分别对典型振动信号进行对比分析,得到了不同爆破条件下振动信号的频谱、能量分布特征：软岩巷道掘进爆破振动的主振频率在90～260Hz,而主要能量集中在160-260Hz,振动的持续时间在150ms左右。由于采用微差爆破,振动的瞬时能量出现多个峰值；与质点振动的幅值相对应,瞬时能量最大的是崩落眼装药起爆。深孔松动爆破振动速度只存在一个峰值,主振频率在40-80Hz,振速大于1cm/s的频率分布在45～60Hz,70～100Hz两个范围；而EMD分解表明：主要能量集中在50-100Hz,根据相对能量的大小,整个频率范围内可分成若干个“子频带”。结合现场巷道施工实际情况和岩石物理力学性能测试结果,运用FLAC3D建立了爆破地震波作用下大、小两种巷道计算模型,得到了不同初始地应力、断面尺寸和支护结构条件下开挖后巷道围岩、支护结构的应力和变形特征。结果表明,爆破动载作用下,围岩的应力和位移有所增大,增幅在15%～20%；围岩的应力和变形随初始地应力和巷道断面尺寸的增大而增大,随支护锚杆的长度增加而减小,喷射混凝土的厚度对围岩的应力和变形影响甚微。围岩塑性区的大小同巷道断面和初始地应力最为相关,断面越大、地应力越高,塑性区范围越大；对于高应力状态下,围岩拱顶主要受剪切作用；混凝土喷层的厚度影响着围岩塑性区的发展。混凝土喷层的最大变形出现在拱顶沿巷道走向分布逐渐减小,而最后开挖支护直墙下部拐角处的变形最小；最大弯曲应力是最后开挖支护的截面,受围岩剪应力SXY影响。通过围岩松动范围的声波测试和分析,从另一方面证明了爆破地震效应对软岩巷道围岩的松动范围的影响。对于研究巷道,开挖后围岩松动范围在1.6～1.65m,在爆破地震效应作用下围岩松动范围增大了0.2m左右,约占围岩稳定后松动圈半径的10%。根据爆炸能量和爆破地震波衰减规律、影响因素及其对巷道影响,详细地从爆破能量控制和巷道围岩及支护结构两个方面提出相应的控制对策。更多还原

【Abstract】 The drilling and blasting procedure was still the present main construction method of coalmine, along with the exploitation scale expansion, detonation charge of blasting construction work and the intensity of vibration also increases, the frequent blasting vibration has had influence to security of roadway wall rock and the support structures. For many years, domestic and foreign researchers had did massive research work on the direction law of blasting vibration, the harm mechanism and the control countermeasure and so on, has yielded substantial result, mainly concentrates in the ground project blasting vibration effect influence on the peripheral buildings, blasting vibration effect of tunnel (including road, railroad and hydraulic tunnel) construction to the neighboring tunnel and the wall rock influence, as well as damage caused by excavates blasting vibration effect of large-scale building foundation and underground workshop construction to the wall rock, open-air mine mining blasting vibration and so on, and research of blasting seismic effect on the roadway stability rarely. In the foundation of domestic and foreign correlation research material consults, through vibration monitor on dissimilar conditions of coal mine roadway excavation blasting and deep hole loose blasting, applies the HHT and Wavelet Packet Transform based on the Matlab software, researched questions about vibration characteristic of coal mine construction blasting, it’s influence on roadway wall and support structures and so on. Main researched work and achievements of this paper are as follows:Analysis formation, spread rule and influence factors of blasting energy distribution and blasting seismic wave by theoretically. Establish blast hole decoupling charge blasting model, pressure peak value of blasting stresswave and velocity of blasting vibration on different decouple medium and coefficient were tested and analysised, pressure peak value of blasting stresswave and velocity of blasting vibration decreased along with increasing of decouple coefficient, and both value of water-decouple charge were greater than air-decouple charge.According to the different situation of blasting construction, blasting vibration monitoring and analysis has been carried on, discovered that peak value of horizontal radial direction (roadway moves towards direction) component was the biggest of three direction components in the vibration velocity three, obtained attenuation rule of vibration resultant velocity and its components in all directions, and difference to blasting on ground.Comparative analysis of typical vibration signal by the HHT Transform and Wavelet Packet Transform respectively, obtained frequency spectrum, obtained under the different demolition condition to vibrate the signal the frequency spectrum, energy distribution characteristic of vibration signal under different conditions:master vibration frequency of soft rock roadway excavation in90-260Hz, and the main energy concentrates in160-260Hz, the vibration duration was about150ms. For short-delay blasting, the vibration instantaneous energy appears many peak values, corresponds with the particle vibration peak value, the biggest instantaneous energy was caused by detonated breakage-hole charge. Vibration velocity of deep hole loose blasting only have a peak value, master vibration frequency o in40-80Hz, the frequency of vibration velocity value bigger than1cm/s distributed in two scopes:45-60Hz and70-100Hz; and the EMD decomposition indicated that, main energy concentrates in50-100Hz, according to the relative energy value, the entire frequency range can be divided into three "sub-frequency band", and internal energy value of each frequency band experiences three stages:wave trough→wave crest→new wave trough.According to the roadway construction actual situation and the rock physics mechanics performance test results, two roadway computation models under the blasting dynamic load had established by FLAC3D, obtained stress and deformation characteristic of roadway wall rock and support structure of different initial ground stress, cross section size and support structure conditions under blasting dynamic load. The result indicated that, under blasting dynamic load, stress and displacement of wall rock has increases, increased range in15%～20%; stress and deformation of wall rock increases along with increases of initial ground stress and the roadway section size, reduces along with the increases of support anchor rod length, shotcrete thickness have micro influence to stress and distortion of wall rock. The wall rock plastic area size is most related with the roadway cross section and the initial ground stress, the bigger cross section, the higher ground stress, plastic area scope is bigger; the roadway arch is at the elastic condition, but before has received cutting and tension failure, the side wall is at shearing failure condition, and the floor receives cuts and stretch dual function, certain depth only receives shear action; regarding high ground stress condition, arch of wall rock mainly shear action; thickness of shotcrete affect wall rock plastic area development. The biggest deformation of shotcrete appear in the arch, distribution reduce along the roadway gradually, and the smallest deformation appear in straight wall down corner of latest excavates section; the most flexural stress appear in the latest excavates section, influenced by shearing stress SXY.Loose scope of wall rock tested by sound wave and analyzed, proved influence of blasting vibration effect on wall rock loose scope of soft rock roadway on the other hand. For the researched roadway, the wall rock loose scope in1.6-1.65m after excavates, has increased about0.2m under the blasting vibration effect, it was about10%.According to the decay laws, effect factors and influence of roadways of explosion energy and blasting seismic wave, control plan were given from two aspects of blasting energy control and surrounding rock, supporting structure in detaile.更多还原