爆破荷载作用下岩体振动特征的数值模拟

根据福建牛头山水电站地基岩体爆破开挖监测,运用离散元方法模拟了节理岩体距爆源不同距离处质点的振动速度和频率的变化特征,由此确定岩体质点最大振动速度和振动主频随爆源距离的衰减规律,并得到了距爆源一定距离处质点最大振动速度和振动主频与爆破药量的关系。数值模拟与现场实测的结果表明,用离散元软件UDEC计算得到的岩体振动特征和衰减规律与现场监测结果是基本符合的,误差在工程应用的允许范围之内,因此UDEC用于对岩体动态响应的数值模拟是适合的。     

深厚淤泥爆破挤淤震动效应测试与控制技术

结合工程实例,对深厚淤泥爆破挤淤震动效应进行测试和分析,线性拟合得出震动速度随距离衰减规律,并从控制单段最大药量、选择合理微差时间、调整震动波传播方向3个方面对地震效应控制技术开展了试验研究。试验结果表明,这些措施可以有效地控制地震效应。控制单段起爆药量是最根本因素;在相同装药量的情况下,按照大于200 ms的微差时间进行控制,最大震动速度可减小20 %～30 %,药包中心连线方向的震速比垂直于中心连线方向的震速低15 %～25 %。试验结果可为类似工程提供借鉴。     

非线性回归法求解爆破振动速度衰减公式参数

准确分析场地爆破振动衰减规律是爆破工程设计的基本依据。通过考察爆破振动速度衰减公式中参数的线性回归方法和非线性回归方法,提出了线性残差平方和与非线性（亦即标准残差平方和）的概念,给出了求解衰减公式参数的非线性回归法,并详述了该方法的实现过程。结合工程实例,以标准残差平方和作为爆破振动实测数据与衰减公式拟合值偏差大小的判断依据,分析了线性和非线性回归分析方法得到的萨道夫斯基公式和其修正公式的标准残差平方和。分析结果表明,非线性回归分析方法的准确度明显高于线性回归分析方法;分别采用线性回归和非线性回归方法得到的萨道夫斯基公式和其修正公式的标准残差平方和非常接近,因此,采用两种形式的公式拟合爆破振动衰减规律都是可行的。     

溪洛渡水电站出线竖井爆破振动效应研究

对溪洛渡水电站左岸出线竖井开挖爆破的振动速度进行了现场测试。运用萨道夫斯基公式对测试数据进行回归分析,得到了竖井爆破掘进中地震波传播衰减公式。利用该式预测距离井底高程差为18.2～24.5 m处范围内测点的振动速度,并与实测数据进行对比。结果显示,竖井爆破振动的传播存在高程放大效应,水平振速放大系数约为1.49～2.24,垂直振速放大系数约为1.78～2.73;通过考虑高程效应对萨道夫斯基公式进行了修正,得到考虑高程因子的衰减公式,线性关系显著,对存在高程放大效应的爆破振动预测具有借鉴意义。运用动力有限元分析方法对竖井结构在爆炸冲击波荷载作用下的结构响应进行数值模拟,数值模拟结果与现场测试结果的对比表明,当相对高差不大时,两者整体趋势比较吻合,距离井底0～15 m,振动速度快速衰减,振动速度峰值衰减幅度超过总体幅度的60%;距离井底超过30 m,衰减不超过总幅度的10%。采用岩石-混凝土强度破坏准则对竖井构筑物在爆炸冲击荷载作用下的稳定性进行了强度校核,为竖井后续施工安全提供了参考。     

采矿爆破振动波在岩溶区的传播影响因素分析

为研究不同情况下爆破振动强度衰变规律和振动对岩溶塌陷的影响,为当地矿山合理开采及减少地面塌陷灾害的发生提供可靠依据,对湖南水口山铅锌矿区进行现场爆破振动测试,并利用古丹铅锌矿实测数据作对比分析;试验矿区共布设4条测线,接收8组爆破振动数据。采用萨道夫斯基修正公式对采集的数据进行计算,以爆破产生的振动波频率及振动速度作为测试指标,对实测数据进行提取、处理,确定爆破振动波的频率及其在介质中的传播速度及地震波引发的质点振动峰值振速。试验结果表明:采矿活动是岩溶地面塌陷的主要影响因素;爆破振动波的频率衰减强度与其在岩土体中的传播距离和断层有关,振动波的传播速度受到岩土体性质、岩层结构特征、岩层走向等因素的影响。      

隧道开挖施工的爆破振动监测与控制技术

以万松岭隧道工程开挖为研究对象,对隧道工程开挖施工爆破地震波的振动监测方法及控制技术进行了研究。通过对爆破振动监测结果的回归分析,建立了隧道工程开挖爆破振动传播的数学模型;确立了其传播衰减规律。结合工程实际,提出了修正后的爆破地震波衰减经验数学公式;经对比分析,所得爆破地震波衰减规律公式预测的质点振动速度具有较高的精度。同时,结合该隧道工程开挖爆破施工,从选择合理爆破时差、最大装药量、微差起爆、掘进进尺、预裂爆破等5个方面提出了爆破振动控制技术措施使该隧道开挖施工爆破中的地面振动速度值控制在了安全范围以内,从而确保了施工段地面建筑群的安全和该隧道工程开挖爆破作业的安全。其研究对指导隧道工程开挖爆破施工和保证地面建筑物安全起到了重要作用。     

上下交叉隧道爆破振动控制技术研究

钻爆法是隧道开挖中一种主要的施工方法,爆破开挖不可避免会对围岩产生扰动。以新建走马岗隧道上穿东深供水走马岗引水隧洞工程为背景,开展上下交叉隧道爆破振动控制技术研究。选取与交叉段岩性一致的爆破施工开挖区域进行爆破振动监测,得到了现场爆破施工方案条件下走马岗隧道爆破振动规律。对实测数据进行回归分析,计算得出走马岗地区爆破质点峰值振动速度（PPV）的Sadovsk公式,反演得到控制爆破振动的最大掏槽药量及安全距离,制定出交叉段施工的安全控制范围以及相应的爆破方案。通过数值模拟进行了验证并付于交叉段现场施工。现场监测数据表明,提出的振速控制标准及爆破方案符合安全要求,保证了在建隧道的顺利开挖以及既有隧道的安全运行。研究成果可为类似工程爆破开挖及振动控制提供参考。     

爆破振动参数在地质灾害鉴定中的运用

本文论述爆破振动参数在地质灾害鉴定中的运用。指出在作爆破振动地质灾害鉴定时,除对建筑物的设计、建筑材料、建筑史、用途、结构、内外环境、地基基础、变形特征进行详细的了解记录外,还必须了解其爆破源点与被鉴定对象之间的地质环境,确定其与地形地质条件有关的系数K,衰减指数α,鉴定对象的最大振幅对应的频率、速度、爆破点的位置及炸药用量,计算振动的安全距离与剖面图上两者之间距离进行比较,为鉴定提出合理的证据。     

花岗岩循环爆破振动衰减规律与损伤演化机理试验

为了研究岩石在循环爆破作用下的动力学响应,本文对黑云母花岗岩试块进行了小型爆破试验,利用加速度传感器和声波测试仪,分别对循环爆破荷载下质点振动衰减规律与累积损伤演化机理进行了探析,并对不同装药量下花岗岩试块的裂纹扩展与断裂形态进行了比较。结果表明:萨道夫斯基公式对室内花岗岩试块的爆破振动衰减规律具有较好的适用性,拟合相关参数都处于0.90以上;花岗岩的爆破损伤随着爆破次数的增加而增加,且损伤值随着距爆心距离（爆心距）的增加而降低,近区损伤值迅速降低,降幅约为1.46/m,而中区和远区损伤值降低相对缓慢,约为0.57/m和0.13/m;花岗岩的破坏程度和装药量有较高的关联度,当药量较低时,岩块致裂所需要的爆破次数就越大;随着药量增加到一定程度,岩块在低爆破次数下就会发生破坏;此外,还发现随着装药量的增加,试块爆后破裂的块数呈现增加趋势,如较低药量时试样破裂成2块,较高药量下破裂成3~4块。     

单自由面爆破振动特征的炮孔堵塞长度效应

单自由面爆破条件下作用在岩体上的最有效破坏力小,而阻碍岩体破坏的作用力很大,使炮孔堵塞长度对爆破振动有较大影响。因此,研究单自由面爆破振动特征的炮孔堵塞长度效应有重要意义。进行了小规模的不同堵塞长度的单自由面爆破试验,并模拟了其爆破过程。研究表明,近距范围内爆破振动速度迅速衰减,中远距离爆破振动速度衰减趋缓;随着堵塞长度的增加,场地系数K不断增加,衰减指数? 总体呈上升趋势;数值模拟振动速度值与实测值误差在15%以内;爆破后不同堵塞长度模型的堵塞物底部空腔半径基本相等,约为装药半径的3倍;试验最优堵塞长度为15～20 cm,相同条件下无堵塞爆破对孔口有效应力场影响较大、对孔底有效应力场影响较小     

Artificial neural network or empirical criteria? A comparative approach in evaluating maximum charge per delay in surface mining — Sungun copper mine

Ground vibration due to blasting causes damages in the existence of the surface structures nearby the mine. The study of vibration control plays an important role in minimizing environmental effects of blasting in mines. Ground vibration regulations primarily rely on the peak particle velocity (PPV, mm/s). Prediction of maximum charge weight per delay (Q, kg) by distance from blasting face up to vibration monitoring point as well as allowable PPV was proposed in order to perform under control blasting and therefore avoiding damages on structures nearby the mine. Various empirical predictor equations have proposed to determine the PPV and maximum charge per delay. Maximum charge per delay is calculated by using PPV predictors indirectly or Q predictor directly. This paper presents the results of ground vibration measurement induced by bench blasting in Sungun copper mine in Iran. The scope of this study is to evaluate the capability of two different methods in order to predict maximum charge per delay. A comparison between two ways of investigations including empirical equations and artificial neural network (ANN) are presented. It has been shown that the applicability of ANN method is more promising than any under study empirical equations.     

花岗岩地区地铁隧道爆破振动传播规律研究

青岛为典型花岗岩地区,地铁隧道开挖采用钻爆法。本文首先采用现场实测与统计分析的方法分析了青岛地铁3号线3个工点的隧道爆破监测数据,较为系统地研究了钻爆法施工条件下地表及邻近构筑物的最大振速、主频分布与爆破参数的相关关系,采用线性回归法拟合出包含上述因素的经验公式。采用数值模拟手段,模拟爆破条件下地表及临近建筑物的振动的响应,并将模拟结果与实测数据进行对比,研究主要结论如下:(1)最大振速随比例距离基本呈指数的形式衰减,随着比例距离的增加,最大振速值逐渐减小; (2)爆破引起的振动主频随比例距离分布较为随机,无法建立两者之间的数学模型,主频多在20～70Hz范围内; (3)建筑物内部中三矢量方向上的最大振速均随着楼层的增高呈一定的增加趋势,建筑物外部的地表振速要大于内部质点的速度。     

近距离交叉隧洞爆破对既有隧道的振动影响

结合南山下隧洞下穿温福客运专线钱仓山隧道工程,实时监测近距离交叉隧洞爆破施工对既有隧道的振动影响。实测结果表明,（1）迎爆面位置影响既有隧道断面的爆破振动速度分布;震源距离测点大于30 m时,距离是爆破振动的主要影响因素;震源距离测点小于30 m时,主要影响因素则为装药量与距离。（2）岩体越坚硬完整,爆破振动波传播衰减越慢。采用导洞先行预留光面爆破、导洞爆破掏槽眼和周边眼及底板眼分开起爆、控制最大段装药量等措施,可有效地降低爆破振动影响,控制其对钱仓山隧道的影响,对类似工程有借鉴作用。     

直墙半圆拱巷道爆破震动数值分析

为利于判断巷道围岩在爆破荷载作用下的稳定性及巷道内壁混凝土衬砌的安全,采用ANSYS/LS-DYNA分析了巷道钻爆法掘进爆破荷载作用下震动区岩体的动力响应。结果表明,近区岩体内部爆破压力、单元有效应力、质点振动速度随爆心距的衰减规律基本符合萨道夫斯基经验公式,单元有效应力与质点振动速度的衰减规律具有很强的相关性;巷道围岩临空面上的质点振动速度以沿巷道方向的振动速度为主,巷道横截面内垂直临空面方向次之,横截面内沿临空面方向为最小。巷道同一横截面处各质点的振动波形基本相同,拱顶的振动速度峰值比帮部的要大10%左右,拱与帮的连接处振动速度峰值较小。巷道围岩沿巷道方向临空面上质点振动速度衰减规律也基本符合萨道夫斯基公式,以上分析结果对采用钻爆法进行岩巷施工时,控制近区震动区爆破荷载对结构的影响具有一定的指导作用。     

The analysis of ground vibrations induced by bench blasting at Akyol quarry and practical blasting charts

Ground vibrations arising from excavation with blasting is one of the fundamental problems in the mining industry. Therefore, the prediction of ground vibration components plays an important role in the minimization of environmental complaints. In this study, 582 events were recorded during limestone production at a quarry (Akyol Quarry) during a period of time. The blasting parameters of these shots were also carefully recorded. During the statistical analysis of the collected data, three predictor equations proposed by the United States Bureau of Mines (USBM), Ambraseys–Hendron and Langefors–Kihlstrom were used to establish a relationship between peak particle velocity and scaled distance described by these prediction equations. As a result of this analysis, the most powerful relationship was determined and proposed to be used in this site. And also, this equation was used in the derivation of the practical blasting charts specific to this site as a practical way of predicting the peak particle velocity and maximum charge amount per delay for future blasting.     

Environmental impacts of bench blasting at Hisarcik Boron open pit mine in Turkey

This paper presents the results of ground vibration measurements carried out in Hisarcik Boron open pit mine located on the west side of central Anatolia near Kütahya province in Turkey. Within the scope of this study to predict peak particle velocity (PPV) level for this site, ground vibration components were measured for 304 shots during bench blasting. In blasting operations, ANFO (blasting agent), gelatin dynamite (priming), and delay electric detonators (firing) were used as explosives. Parameters of scaled distance (charge quantity per delay and the distance between the source and the station) were recorded carefully and the ground vibration components were measured for all blast events using two different types of vibration monitors (one White Mini-Seis and one Instantel Minimate Plus Model). The absolute distances between shot points and monitor stations were determined using GPS. The equation of square root scaled distance extensively used in the literature was taken into consideration for the prediction of PPV. Then, the data pairs of scaled distance and particle velocity obtained from the 565 event records were analyzed statistically. At the end of statistical evaluation of the data pairs, an empirical relation which gives 50% prediction line with a reasonable correlation coefficient was established between PPV and scaled distance.     

Comparative Study on Calculation Methods of Blasting Vibration Velocity

Due to the extreme complexities in rock blasting and difficulties in theoretical or numerical analysis, and the enormous consumption of explosives in mining and construction operations, empirical or semi-empirical formulae for blasting vibration velocity (BVV) were obtained from observations and measurements in field blast tests and are still widely used all over the world. This paper investigates the fitting degree and characteristics of several calculation methods for BVV based on 34 sets of data samples from 27 projects belonging to 4 types. The results indicate that both the cube-root scaling formula and the square-root scaling formula have relatively good fitting degree, while the multiple regression analysis can give the best fitting outcome if the sample space satisfies certain requirements. Whether the cube-root scaling formula or the square-root scaling formula is chosen to analyze the relationship between BVV and scaled distance depends on the average scaled distance under cubic-root scaling. If the average scaled distance is over 0.1, the cube-root scaling formula should be used; otherwise, the square-root scaling formula should be used. Bigger samples integrated from data samples of different projects but in the same type were then analyzed to get the empirical relations for different types of projects. The correlation coefficients of these relations are quite good, thus these relations can be used for reference in other similar projects. This paper then discusses the physical meanings of parameters in different formulae, sample selection and parameter choice for BVV. It suggests that the current calculation methods for explosive charge, blasting-to-monitoring distance and scaled distance need to be improved. It also concludes that the integrated BVV from velocity components in three-dimensions is more reasonable on a theoretical basis. It can yield good results in predicting the blasting vibration, and should be used as widely as possible.     

岭澳核电站二期工程基岩爆破安全阈值分析

核电站基础爆破开挖过程中必须严格控制岩体爆破损伤深度,确保建基面安全。以广东岭澳核电站二期工程基础爆破开挖为例,通过现场爆破振动监测、岩体声波试验以及数值模拟,综合分析了岩体爆炸振动衰减规律和损伤特征,研究了距爆源一定距离处岩体振动速度与损伤特征的关系,提出了岭澳核电站二期工程岩体爆炸损伤深度的控制方法,确定了相应的安全阈值。分析结果表明,岭澳核电站二期工程基础爆破开挖时,当距爆源30 m处的岩体质点振动速度不超过5 cm/s时,可保证下卧基岩的损伤深度小于2 m,确保建基岩完整性。