Double-face intelligent hole position planning method for precision blasting in roadways using a computer-controlled drill jumbo

To solve the uneven burden of same-type holes reducing the blasting efficiency due to the limitation of drilling equipment,we need a double-face program-controlled planning method for hole position parameters used on a computer-controlled drilling jumbo.The cross-section splits into even and uneven areas.It also considers the uneven burden at the hole’s entrance and bottom.In the uneven area,various qualifying factors are made to optimize the hole spacing and maximize the burden uniformity,combined with the features of the area edges and gridbased segmentation methods.The hole position coordinates and angles in the even area are derived using recursion and iteration algorithms.As a case,this method presents all holes in a 4.8 m wide and 3.6 m high cross-section.Compared with the design produced by the drawing method,our planning in the uneven area improved the standard deviation of the hole burden by 40%.The improved hole layout facilitates the evolution of precise,efficient,and intelligent blasting in underground mines.

Propagation and Coalescence of Blast-Induced Cracks in PMMA Material Containing an Empty Circular Hole Under Delayed Ignition Blasting Load by Using the Dynamic Caustic Method

In this paper,dynamic caustic method is applied to analyze the blast-induced crack propagation and distribution of the dynamic stress field around an empty circular hole in polymethyl methacrylate(PMMA)material under delayed ignition blasting loads.The following experimental results are obtained.(1)In directional-fracture-controlled blasting,the dynamic stress intensity factors(DSIFs)and the propagation paths of the blast-induced cracks are obviously influenced by the delayed ignition.(2) The circular hole situated between the two boreholes poses a strong guiding effect on the coelesence of the cracks,causing them to propagate towards each other when cracks are reaching the circular hole area.(3)Blast-induced cracks are not initiated preferentially because of the superimposed effect from the explosive stress waves on the cracking area.(4) By using the scanning electron microscopy(SEM)method,it is verified that the roughness of crack surfaces changes along the crack propagation paths.

Study on the Prediction of Rice Blast Based on the Unbiased GM (1,1) Model

To create a new prediction model, the unbiased GM （1,1） model is optimized by the five-point slide method in this paper. Then, based on the occurrence areas of dce blast in Enshi District during 1995 -2004, the new model and unbiased GM （1, 1 ） model are applied to predict the occurrence areas of rice blast during 2005 -2010. Predicting outcomes show that the prediction accuracy of five-point unbiased sliding optimized GM （1, 1 ） model is higher than the unbiased GM （1,1） model. Finally, combined with the prediction results, the author provides some suggestion for Enshi District in the prevention and control of rice blast in 2010.

Inertisation options for BG method and optimisation using CFD modelling

Spontaneous combustion(sponcom) is one of the issues of concern with the blasting gallery(BG) method of coal mining and has the potential to cause fires, and impact on production and safety, greenhouse gas(GHG) emissions and huge costs involved in controlling the aftermath situations. Some of the research attempts made to prevent and control coal mine fires and spontaneous combustion in thick seams worked with bord and pillar mining methods are presented in this paper. In the study, computational fluid dynamics(CFD) modelling techniques were used to simulate and assess the effects of various mining methods, layouts, designs, and different operational and ventilation parameters on the flow of goaf gases in BG panels. A wide range of parametric studies were conducted to develop proactive strategies to control and prevent ingress of oxygen into the goaf area preventing spontaneous combustion and mine fires.

Distinct element modelling of fracture plan control in continuum and jointed rock mass in presplitting method of surface mining

Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation. Presplitting is one of the most common methods which is used in many open pit mining and surface blast design. The purpose of presplitting is to form a fracture plane across which the radial cracks from the production blast cannot travel. The purpose of this study is to investigate of effect of presplitting on the generation of a smooth wall in continuum and jointed rock mass. The 2D distinct element code was used to simulate the presplitting in a rock slope. The blast load history as a function of time was applied to the inner wall of each blasthole. Important parameters that were considered in the analysis were stress tensor and fracturing pattern. The blast loading magnitude and blasthole spacing and jointing pattern were found to be very significant in the final results.

Modelling of blast-induced damage in tunnels using a hybrid finite-discrete numerical approach

This paper presents the application of a hybrid finite-discrete element method to study blast-induceddamage in circular tunnels. An extensive database of field tests of underground explosions above tunnelsis used for calibrating and validating the proposed numerical method; the numerical results areshown to be in good agreement with published data for large-scale physical experiments. The method isthen used to investigate the influence of rock strength properties on tunnel durability to withstand blastloads. The presented analysis considers blast damage in tunnels excavated through relatively weak（sandstone） and strong （granite） rock materials. It was found that higher rock strength will increase thetunnel resistance to the load on one hand, but decrease attenuation on the other hand. Thus, undercertain conditions, results for weak and strong rock masses are similar. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

DETERMINATION OF MICROCRACK BOUNDARY RESULTING FROM ROCK BLASTING WITH SEISMIC TRAVELTIME TOMOGRAPHY

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钻爆法机械化施工隧道随钻地震波超前地质探测技术研究

为适应我国隧道建设机械化、智能化、无人化发展趋势,围绕钻爆法机械化施工隧道,提出以凿岩台车破岩振动为震源的钻爆法机械化施工隧道随钻地震波超前地质探测技术。针对凿岩台车多震源连续激发带来的地震数据波场混叠、有效信息难以识别问题开展相关研究,提出VMD-SVD-RobustICA三臂混合先导信号分离方法与脉冲反褶积-小波域互相关地震记录重构方法,可实现三臂混合先导信号的分离与有效反射信号的提取。工程实践证明,利用凿岩台车搭载式无线高精度探测装备,该技术可初步实现“边钻边探”,降低预报环节对钻爆法机械化施工隧道正常施工带来的影响。最后,明确该技术目前存在的问题及解决思路。

Numerical study on the fracturing mechanism of shock wave interactions between two adjacent blast holes in deep rock blasting

With the application of electronic detonators, millisecond blasting is regarded as a signifi cant promising approach to improve the rock fragmentation in deep rock blasting. Thus, it is necessary to investigate the fracturing mechanisms of short-delay blasting. In this work, a rectangle model with two circle boreholes is modeled as a particles assembly based on the discrete element method to simulate the shock wave interactions induced by millisecond blasting. The rectangle model has a size of 12 × 6 m (L × W) and two blast holes have the same diameter of 12 cm. The shock waves are simplifi ed as time-varying forces applied at the particles of walls of the two boreholes. Among a series of numerical tests in this study, the spacing between two adjacent boreholes and delay time of millisecond blasting are considered as two primary variables, and the decoupling charge with a coeffi cient of 1.5 is taken into account in each case. The results show that stress superposition is not a key factor for improving rock fragmentation (tensile stress interactions rather than compressive stress superposition could aff ect the generation of cracks), whereas collision actions from isolated particles or particles with weakened constraints play a crucial role in creating the fracture network. The delay time has an infl uence on causing cracks in rock blasting, however, whether it works heavily depends on the distance between the two holes.

高海拔铁路隧道斜井机械化配套与快速施工

为解决高海拔高寒地区斜井施工存在气压低、含氧量低、温差大、严寒干燥等问题,以某高海拔铁路隧道斜井工程为背景,结合围岩等级、断面大小、海拔高度,根据斜井施工机械化配套原则,提出高海拔陡坡长斜井机械化安全快速进洞施工工法,并选配超前支护、钻爆、装运、喷锚支护、衬砌等机械化作业线的成套设备。基于高度机械化的设备配套,提出“快挖、快运、快支”的高效施工技术以及各工序快速衔接工艺。以控制围岩变形为核心,构建一套积极干预加固围岩、注重早期支护并快速闭合的主动支护体系。结果表明:与普通钻爆法施工相比,采用三臂凿岩台车高度机械化配套施工效率高,月最快进尺为180 m,较人工钻爆法施工月进尺为130 m相比提高了近30%,施工质量稳定,作业人员投入少,且拱顶沉降和周边收敛均小于规范要求值,衬砌强度可靠,可实现高海拔小断面隧道“快挖、快支、主动支、快封闭”。

间隔装药的殉爆起爆技术在露天矿山爆破中的应用

为了降低西沟露天石料厂的采石爆破成本,提高经济效益;应用空气袋间隔装药装置技术进行了150 mm炮孔和100 mm炮孔的爆破实验对比,同时进行了露天炮孔孔内反向和正向起爆殉爆试验对比。结果表明:采用炮孔中部空气袋间隔装置的露天矿台阶爆破,电子雷管起爆一端装药之后再利用其爆轰波殉爆起爆另一端装药,孔径大的炮孔比孔径小的炮孔殉爆起爆的爆破效果好;采用殉爆起爆技术后,做到了节能减排和提效;反向起爆爆破法与正向起爆爆破法相比,爆破效果更好。

山区铁路隧道钻爆法施工安全风险演化路径及防控研究

山区铁路隧道钻爆法施工安全风险突出,探索安全风险演化路径并提出安全风险防控措施,对减少安全事故发生意义重大。针对山区铁路隧道钻爆法施工特点,运用文本挖掘分析历史安全事故资料、铁路标准规范资料、现场安全风险评估报告、相关研究文献资料等,结合“4M1E”理论和专家经验识别山区铁路隧道钻爆法施工主要安全风险因素和安全风险事件。采用质性分析法,结合现场调研和专家访谈,提取安全风险因素间、安全风险事件间、安全风险因素及事件间相互关系,构建山区铁路隧道钻爆法施工安全风险演化网络模型。基于风险演化理论、复杂网络理论等,利用度中心性、介数中心性、聚类系数、特征向量中心性、中间中心度等多项指标分析山区铁路隧道钻爆法施工安全风险演化网络节点重要度、边的关键性,从而确定关键链演化路径,并提出安全风险防控措施。研究结果表明:山区铁路隧道钻爆法施工安全风险包括人员、设备、技术、管理、环境5类共41个主要安全风险因素和塌方、突泥涌水等6个主要安全风险事件,确定了安全风险演化网络中8个关键节点、20条关键边和3条关键链,针对关键链风险演化路径提出了安全风险防控措施,为提高山区铁路隧道钻爆法施工安全风险管理水平提供参考。

STRESS AND ENERGY TRANSFER OF WATER COUPLING BLASTING

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In-vitro vs in-vivo Inoculation: Screening for Resistance of Australian Rice Genotypes Against Blast Fungus

To assist with rapid screening for rice blast resistance as a precursor in a breeding program, the susceptibility to rice blast of 13 rice genotypes from Australia was evaluated in May to June 2013 using three distinct inoculation methods（spot, filter paper and standard methods） at seedling, vegetative and reproductive stages. The results revealed that the spot and filter paper inoculation methods were successful in discerning susceptibility to the rice blast disease（P ≤ 0.05）. Disease susceptibility declined significantly from the vegetative to reproductive stages. The standard method was conducted at three different stages for pot plants grown inside the mist house. However, low temperatures did not produce disease symptoms except in a few genotypes. Among the 13 rice genotypes screened, AAT9 expressed a highly resistant response, and AAT4, AAT6, AAT10, AAT11, AAT13, AAT17 and AAT18 expressed resistance at various stages. The results will be useful for selecting elite genotypes for disease tolerance where rice blast is prevalent. In addition, the resistant genotypes can serve as a gene pool used in breeding programmes to develop new resistant genotypes.

基于离散元方法的急倾斜极薄矿脉机械化开采爆破参数仿真优化

急倾斜极薄矿脉留矿法开采爆破空间规整平齐是实现小型采矿机器人高效通行和稳定作业的关键因素。为了提高狭小空间爆破光面控制效果,采用离散元方法和黏结颗粒模型耦合仿真方法,开展了不同炮孔参数条件下急倾斜极薄矿脉爆破模拟,以爆破空间轮廓规整性系数为评价指标,对急倾斜极薄矿脉炮孔布置方式和参数进行了优化。研究结果表明:同等排距和孔距条件下,矩形方式布孔的爆破规整性系数最高,矩形+间隔空孔布孔方式爆破规整性系数次之,之字形炮孔布置方式爆破效果最差;结合爆破经济性指标和采场断面规整性系数综合考虑,对于急倾斜极薄矿脉机械化开采,推荐采用矩形+间隔空孔装药的爆破方式,炮孔排距0.4 m,孔距0.8 m。

倾斜工作面面向断层开采煤柱失稳机制及稳定性控制

以某矿面向断层开采的5302工作面为工程背景,模拟了工作面回采过程中断层及断层周围煤岩体垂直应力、塑性区及断层滑移演化规律,提出了断层煤柱的合理尺寸,并制定了卸压方案。研究结果表明:工作面回采期间断层及断层周围煤岩体受构造应力与采动应力叠加作用下应力高度集中,容易诱发冲击地压;微震、应力在线监测结果对比分析表明,制定的爆破断顶、钻孔卸压技术方案能够有效降低应力集中程度,避免工作面面向断层开采时诱发冲击危险。

新型爆破掘进施工方式与常规爆破施工方式的对比

本文主要分析对比了近些年来工程施工中出现的几种新型掘进施工方法的优缺点,并通过与常规爆破施工方法进行对比,得出了常规爆破施工方法是完全无法被替代的掘进施工方式。本文旨在为爆破掘进施工方法的选择、爆破行业的稳定发展提供可借鉴的经验。

钻爆法施工隧道超挖对于混凝土超耗的定量关系研究

混凝土超耗居高不下是目前钻爆法施工隧道面临的形势和现状,在影响混凝土超耗的诸多因素中,超挖是其主要因素之一。本文通过大量的样本隧道,采用3D激光扫描仪测量设备,对隧道实际超挖进行实测;采用统计分析法、误差极限值法、对比分析法等数据分析方法,分析出隧道超挖的影响因素,计算因此造成的隧道混凝土超耗情况,从而得出隧道实际超挖与现行规范允许超挖的差距对混凝土超耗的影响程度,为隧道施工超挖控制提供借鉴。

基于数值模拟的压入式通风隧道粉尘运移规律研究

为解决隧道钻爆作业施工期产生大量粉尘污染的问题,以四川卡拉水电站左岸交通隧道为研究对象,依据气固两相流理论,运用FLUENT软件构建了隧道粉尘扩散分布模型,对风流场分布特征和粉尘颗粒的运移规律进行模拟计算。结果表明:隧道风流场被划分为3个区域:涡流区、过渡区和稳定区,不同区域风流场特性有很大差异;风筒出口发射的高速气流运动过程中会逐渐扩大接触断面,并形成风幕;气流运动会导致隧道横截面方向粉尘质量浓度左低右高,但最后浓度分布将趋于平均;随着风速的增加,降尘速率增大,但有可能导致二次扬尘。最后,综合实际工程条件和施工要求,选择风速为24 m/s为最优排尘风速。研究成果可为隧道等地下工程通风系统改进和抑尘效果优化提供参考。

大断面隧道掘进爆破分区优化设计研究

某隧道工程地质、水文地质等条件均较复杂,采用原爆破设计施工方案(常规“两步”台阶法)常出现隧道断面超挖、冒顶等情况,严重制约了隧道工程建设,无法满足隧道工程建设目标,需对原设计方案参数进行优化调整。根据隧道断面规格、工程岩性等条件,为控制隧道顶板暴露面积、防止顶板冒落及降低支护成本等,优选“CRD法”“三步台阶”及“两步台阶”作业法,开展隧道爆破分区掘进试验研究,并严格控制隧道顶板周边孔布置间距(400~450 mm)。为降低隧道爆破数码电子雷管使用量,隧道顶部周边孔采用导爆索与32 mm乳化炸药绑扎(胶布缠绕),各炮孔间通过导爆索传爆,取代传统光面爆破参数。现场施工结果表明:Ⅴ级围岩隧道采用“CRD法”施工,顶部超、欠挖量满足技术规范;Ⅳ级围岩隧道采用“三步台阶”施工,炮孔残留率达60%~72%;Ⅲ级围岩隧道采用“两步台阶”施工,炮孔残留率达84%~94%。优化传统光面爆破参数布置,利用导爆索实现顶部周边孔孔间传爆、孔内起爆,可总体降低数码电子雷管使用量,降低爆破成本约18.5%,该技术可为类似隧道工程及地下矿山巷道掘进爆破提供参考。