Attenuation of rock blasting induced ground vibration in rock-soil interface

Blasting has been widely used in mining and construction industries for rock breaking.This paper presents the results of a series of field tests conducted to investigate the ground wave propagation through mixed geological media.The tests were conducted at a site in the northwestern part of Singapore composed of residual soil and granitic rock.The field test aims to provide measurement data to better understand the stress wave propagation in soil/rock and along their interface.Triaxial accelerometers were used for the free field vibration monitoring.The measured results are presented and discussed,and empirical formulae for predicting peak particle velocity (PPV) attenuation along the ground surface and in soil/rock were derived from the measured data.Also,the ground vibration attenuation across the soil-rock interface was carefully examined,and it was found that the PPV of ground vibration was decreased by 37.2% when it travels from rock to soil in the vertical direction.

Effects of additives on the phase transformation, occurrence state, and the interface of the Ti component in Ti-bearing blast furnace slag

The influences of additives on the phase transformation, occurrence state, and the interface of the Ti component in Ti-bearing blast furnace slag were investigated. After oxidation, most of the Ti component in the slag was enriched into the perovskite phase, which served as the Ti-rich phase during the crystallization process. The phase transformation, occurrence state, and the interface of the Ti component were observed to be affected by the addition of different types of agents. During the oxidation process, titanaugite and Ti-rich diopside phases gradually transformed into non-Ti phases（anorthite： CaMgSi2O6 and CaAl2Si2O8） in the form of dendrites or columns, which were observed to be distributed at the surface of the perovskite phase. Several more cracks appeared along the grain boundaries of the perovskite phase after the addition of P2O5, facilitating the liberation of the perovskite phase. Composite additives combining both an acid and a base, such as CaO ＋ CaF2 or P2O5 ＋ CaF2, were used. We observed that the disadvantages of using single additives were successfully overcome.

序列同源性分析软件Blast的WEB界面构建及其应用

基于局域网 (Intranet)内的PC/Linux服务器 ,构建了序列同源性分析软件Blast的WEB界面 .局域网内的所有计算机均可通过WEB方式访问该服务器进行公共数据库和自建数据库的查询 ,具有保密、高效、免费的优点 ,能够满足实验室和研究院所的大规模。

邯钢新区汽运铁水“一罐制”技术特点

从运输方式、铁水运输车、界面布置、运输流程、运行罐数管理、新技术的支持及安全管控等方面,阐述了邯钢新区汽运铁水“一罐制”技术的应用状况。实践表明:在1号高炉日产量8600/d的情况下,在线铁水运输车数量为9台,铁水罐数量为10~12个,铁水罐周转率平均达到6.0次/d左右,铁水温降减小到95℃左右;铁水运输车铁水装入偏差控制在+0.5t以内,炼钢直兑比例可达到99.5%,炼钢平均提高人炉铁水温度60~70℃。认为汽运铁水“一罐制”技术具有布局紧凑、投资低、生产效率高、铁水罐周转率高、铁水温降低及节能环保等特点,有着较好的应用前景。

Application of Air-cooled Blast Furnace Slag Aggregates as Replacement of Natural Aggregates in Cement-based Materials：A Study on Water Absorption Property

The influence of air-cooled blast furnace slag aggregates as replacement of natural aggregates on the water absorption of concrete and mortar was studied, and the mechanism was analyzed. The interface between aggregate and matrix in concrete was analyzed by using a micro-hardness tester, a laser confocal microscope and a scanning electron microscope with backscattered electron image mode. The pore structure of mortar matrixes under different curing conditions was investigated by mercury intrusion porosimetry. The results showed that when natural aggregates were replaced with air-cooled blast furnace slag aggregates in mortar or concrete, the content of the capillary pore in the mortar matrix was reduced and the interfacial structure between aggregate and matrix was improved, resulting in the lower water absorption of mortar or concrete. Compared to the concrete made with crushed limestone and natural river sand, the initial absorption coefficient, the secondary absorption coefficient and the water absorption capacity through the surface for 7 d of the concrete made from crushed air-cooled blast furnace slag and air-cooled blast furnace slag sand were reduced by 48.9%, 52.8%, and 46.5%, respectively.

Numerical Analysis of Blast Furnace Performance Under Charging Iron-Bearing Burdens With High Reducibility

The reducibility of iron-bearing burdens was emphasized for improving the operation efficiency of blast furnace. The blast furnace operation of charging the burdens with high reducibility has been numerically evaluated using a multi-fluid blast furnace model. The effects of reaction rate constants and diffusion coefficients were investigated separately or simultaneously for clarifying the variations of furnace state. According to the model simulation results, in the upper zone, the indirect reduction of the burdens proceeds at a faster rate and the shaft efficiency is enhanced with the improvement under the conditions of interface reaction and intra-particle diffusion. In the lower zone, direct reduction in molten slag is restrained. As a consequence, CO utilization of top gas is enhanced and the ratio of direct reduction is decreased. It is possible to achieve higher energy efficiency of the blast furnace, and this is represented by the improvement in productivity and the decrease in consumption of reducing agent. The use of high-reducibility burdens contributes to a better performance of blast furnace. More efforts are necessary to develop and apply highreducibility sinter and carbon composite agglomerates for practical application at a blast furnace.

动静载下全长砂浆锚固玻璃钢锚杆受力及失效特征分析

针对爆破动载作用下玻璃钢锚杆的损伤失效问题,利用FLAC3D软件建立全长砂浆锚固玻璃钢锚杆数值计算模型,研究了预紧力静载和爆破动载下锚杆杆体、杆体与砂浆界面、砂浆与围岩界面的受力及失效特征,同时分析了动载强度、围岩及砂浆强度对锚杆受力的影响规律,并与现有试验结果对比,验证了研究结果的可靠性。研究结果表明:全长砂浆锚固玻璃钢锚杆最大轴向应力随动载强度的增大呈线性增大而随围岩或砂浆强度的增大而减小,且轴向应力分布较金属锚杆更为集中;两个界面剪应力均是沿杆体轴向迅速增大至峰值后快速减小为0,之后黏结性能相对较弱的界面先发生脱黏破坏,脱黏位置剪应力下降至残余黏结强度,同时剪应力峰值向孔底转移;玻璃钢锚杆剪应力分布较金属锚杆更集中,峰值位置更加突出;动载强度越大,破坏界面的脱黏长度和剪应力分布范围越大,而未破坏界面的剪应力峰值位置也会向孔底转移;围岩强度越大或砂浆强度越小,剪切破坏越倾向于发生在杆体−砂浆界面,反之,则越倾向于发生在砂浆−围岩界面。

新疆大石峡水利枢纽混凝土碱-硅酸反应抑制研究

新疆大石峡水利枢纽混凝土选用的骨料存在碱活性,可能导致工程产生碱骨料破坏问题,本文研究了当地粉煤灰和矿粉对碱-硅酸反应(ASR)的影响,并采用XRD和SEM-EDS测试分析了水化产物和界面过渡区的形态。结果表明:粉煤灰掺量≥20%(质量分数)或矿粉掺量≥40%(质量分数)都能显著抑制碱-硅酸反应;在纯水泥样品界面过渡区可以观察到无定形相,在含有粉煤灰或矿粉的样品中未观察到无定形相,这意味着碱-硅酸反应发生在纯水泥样品中;添加粉煤灰或矿粉降低了界面过渡区物相的Ca/Si摩尔比,抑制了碱-硅酸反应。

我国隧道智能建造技术发展与展望

阐述隧道智能建造的总体目标与技术路径,对目前盾构/TBM法和钻爆法隧道应用的一系列智能建造技术进行介绍。结合行业前沿,对隧道智能建造面临的主要问题和发展前景进行论述与展望。研究显示:1)隧道建造由机械化升级到智能化是社会发展的必然趋势。2)隧道智能建造发展大致可以划分为初级和高级2个阶段,初级阶段隧道建造仅在个别场景、简单作业方面实现智能装备作业,高级阶段是指实现了隧道建造多场景、多工序智能感知、决策、互联与协同。3)智能预制生产线+现场智能化装配+数字化管控将成为隧道智能建造的发展趋势。4)智能建造将为隧道行业注入新活力,促进行业升级。

Performance of soft-hard-soft （SHS） cement based composite subjected to blast loading with consideration of interface properties

This paper presents a combined experimental and numerical study on the damage and performance of a soft-hard-soft （SHS） multi-layer cement based composite subjected to blast loading which can be used for protective structures and infrastructures to resist extreme loadings, and the composite consists of three layers of construction materials including asphalt concrete （AC） on the top, high strength concrete （HSC） in the middle, and engineered cementitious composites （ECC） at the bottom. To better characterize the material properties under dynamic loading, interface properties of the composite were investigated through direct shear test and also used to validate the interface model. Strain rate effects of the asphalt concrete were also studied and both compressive and tensile dynamic increase factor （DIF） curves were improved based on split Hopkinson pressure bar （SHPB） test. A full-scale field blast test investigated the blast behavior of the composite materials. The numerical model was established by taking into account the strain rate effect of all concrete materials. Furthermore, the interface properties were also considered into the model. The numerical simulation using nonlinear finite element Both the numerical and field blast test indicated that the software LS-DYNA agrees closely with the experimental data SHS composite exhibited high resistance against blast loading

铀矿爆破增渗改造的爆生气体返排规律研究

为了分析爆破后裂隙内气体的返排规律,基于气液两相流规律,借助相场方法对两相流界面进行追踪,模拟了驱替压差、裂隙开度和接触角等对裂隙内气体返排过程中水气界面形态和位置的时空演化规律;通过响应面法,分析了各影响因素的显著性,最终建立了气体返排效果评价流程。研究表明,单因素分析裂隙内气体返排效率同驱替压差、裂隙开度成正比。通过多因素分析,以气体排出速率作为评价指标,建立了CO_(2)气体返排效果评价流程。该研究内容对低渗砂岩型铀矿的爆破增渗后气体返排工艺具有一定的理论参考和现场指导意义。

白象山铁矿一步骤下向孔预控界面爆破试验研究

针对地下矿山一步骤回采采场轮廓和超欠挖控制难题,以白象山铁矿为工程背景,基于采场边界控制原理,在井下开展下向孔预控界面爆破试验。试验结果表明,采场预控界面爆破技术是提升采场轮廓控制质量的有效手段,可以形成清晰的半壁孔,整体上将采场边界不平整度控制在15 cm以内。结合不同区域矿岩特性的差异,提出了推荐预控界面爆破参数,对于类似条件采场控制具有指导借鉴作用。

大型高炉集成技术及装备的应用实践

高炉大型化是炼铁发展的趋势,在大型高炉建设中研发、集成了一系列技术先进、成熟可靠、节能降耗、高效长寿、绿色低碳的集成技术及装备,重点对新型铁钢界面技术、炉顶均压煤气回收技术、高炉长寿综合技术、高炉顶燃式热风炉技术、全干法布袋除尘技术、现代化出铁场综合技术、高富氧大喷煤技术等主要技术和装备进行详细阐述并予以应用实践。将该系列技术成功应用到山钢日照公司5100 m^(3)高炉上,高炉投产后主要技术经济指标均达到了国内领先水平,并推广应用到莱芜分公司3800 m^(3)高炉和邯钢老区搬迁3700 m^(3)高炉中,为实现高炉“高效、优质、低耗、长寿、环保”的目标打下了坚实的基础。

矿渣对界面过渡区微力学性质的影响

采用纳米压痕技术测试了矿渣取代水泥的质量分数分别为0%,30%,50%,80%时的混凝土中实际界面过渡区及邻近区域的纳米压痕硬度和弹性模量分布以了解矿渣对混凝土界面过渡区微力学性质的影响。试验结果表明:矿渣掺量为30%时,距集料表面25μm以内区域的弹性模量、纳米压痕硬度明显低于距集料表面25μm以外的区域,而当矿渣掺量达到50%时,弹性模量和纳米压痕硬度沿界面的变化不显著;随矿渣取代水泥质量分数的增加,基体与界面过渡区之间压痕硬度、弹性模量的差值降低,从而使界面过渡区得到强化。

基于Matlab GUI的爆破粉尘可视化软件设计与实现

目前关于爆破粉尘可视化的研究报道较少。在分析城市拆除爆破粉尘的基础上对高斯模型进行修正构建了改进型高斯扩散模型,采用Matlab GUI工具箱对所构建模型进行了可视化软件设计。软件可以用来计算粉尘源强,并能够精确绘制该粉尘源强条件下爆破粉尘浓度分布三维图及其二维图。采用Matlab GUI工具箱所绘制的二维和三维图形能够直观、形象的反应任意时间点任意坐标精度以及一定范围内的爆破工程粉尘的扩散状态。

改良喷砂表面处理提高钛牙种植体骨结合的界面生物力学研究

目的 :研究改良喷砂表面处理对钛牙种植体骨界面剪切强度的影响 ,从界面生物力学角度证实改良喷砂表面处理在钛牙种植体中应用的可行性和应用价值。方法 :将光滑表面钛种植体与改良喷砂表面种植体随机植入狗股骨内侧髁 ,分别于植入后 2、4、12周取材 ,Instron电子拉伸试验机检测种植体骨界面的剪切强度。扫描电镜与 X-射线能谱分析仪观察植入 12周拔出的种植体表面 ,并进行元素分析。结果 :改良喷砂表面组骨界面剪切强度明显高于光滑表面组 ,约高出 4倍 ,且植入 2周即已获得超出光滑表面组 12周所能达到的最大强度。植入 12周后拔出的改良喷砂表面种植体表面经扫描电镜观察与 X-射线谱分析 ,提示种植体表面大部分被覆骨组织 ,粗糙表面的二级窝洞内充满骨样组织。结论 :改良喷砂表面处理所获得的粗糙表面可以大大地提高牙种植体骨界面的结合强度。

土石交界地层隧道爆破振动控制技术研究

以空树河铁路隧道土石交界地层条件为研究背景,分析隧道地层地质条件和应力分布情况,并开展了隧道爆破方案设计和振动监测设计。分析结果表明:①当土石交界面为水平分布时,中下台阶具有较为明显的应力集中现象;土石交界面倾斜的情况下,内力呈现不对称分布,该类地层会造成隧道结构轴力和安全系数突变,但基本不影响弯矩。②当土石分界面位于掌子面时,振动波对混凝土钢拱架影响较为明显,顶拱部位振动速度最大可达7.97.9 cm/s,拱腰位置最小0.1-1.2 cm/s,受拉破坏的区域最大深度为顶拱以下2.6 m,分布于土石交界地层以上。③土石分界面位于顶拱以上时,土石分界面振动速度高达11.5 cm/s,大于其他开挖区;当振波穿过土石界限后振速衰减变快,受拉破坏最大深度为1.12 m。通过精细爆破设计、信息化施工、合理设置爆破参数和预加固措施,采用三台阶施工法有效控制土石交界地层隧道的爆破振害。

同轴电极固液界面放电的碎石模式

为了提高高压脉冲碎石效率,开展了同轴电极固液界面碎石实验研究。采用高电压脉冲放电原理,设计了同轴电极平面布置在固体介质表面,利用液体绝缘的高电压脉冲放电碎石实验装置,开展了不同液相绝缘介质中不同固相介质条件下的高电压脉冲碎石实验。经过对记录的电压电流波形进行比较分析,抽取了可能的区分不同放电模式的参数特征。结果表明:液体介质击穿时延比相应环境下固体介质击穿时延大,且击穿时延与液体介质的导电粒子含量负相关;液体介质击穿电阻变化系数比其环境下固体介质击穿电阻变化系数大至少一个数量级。根据分析得出击穿时延与击穿过程电阻变化系数可以作为判别放电模式的参数特征。

高炉矿渣改善固井水泥界面胶结性能研究

基于对双界面封固系统的认识和对高炉矿渣物化特性的分析，研制了用于模拟圃井界面胶结的试验装置，利用胶结强度模拟试验等方法评价了高炉矿渣水泥体系的性能。结果表明，矿渣和激活剂加量范围分别为25％～35％和3．5％～4．5％时能明显提高水泥第一界面的胶结强度，且受养护温度的影响较大；矿渣水泥在于心、水湿和有滤饼3种界面条件下的第二界面胶结性能都优于基浆，第二界面胶结强度远小于第一界面，体系性能满足现场固井要求。试验证实了模拟装置的可行性，高炉矿渣独特的水化特点、良好的界面亲和性及与水泥间的颗粒级配为解决固井工程中的界面胶结问题提供了实际可行的解决方案和必要的理论依据。

弹丸高速斜侵彻入水流场显示的初步研究

为认识弹丸高速斜侵彻入水的气/水界面变形破碎、入水空泡和水中冲击波传播,利用可变发射角立式二级轻气炮发射高速弹丸,结合高速激光阴影和纹影流场显示,给出了高速弹丸斜侵彻入水流场的演化图像。结果表明:当弹丸速度在350 m/s附近时,弹丸尾部气流会越过弹丸头部产生冲击波,因为时间短且水惯性大,冲击波在气/水界面反射但不会影响弹丸姿态和气/水界面。弹丸斜侵彻在水中产生冲击波系,气/水界面发生形变和破碎("碎片云"),水中产生冲击波系和空化气泡区,难以识别气泡和"碎片云"的边界,不同头部构型弹丸会影响气泡和"碎片云"体积大小以及水下弹道稳定性。弹丸速度为1.8 km/s时,碎片云体积大于水下空泡体积,但流场结构和350 m/s情形相似。采用立式二级轻气炮和流场显示系统,为研究高速弹丸斜侵彻入水现象提供了新的途径。