Characterization of Effective Parameters in Abrasive Waterjet Rock Cutting

The rock cutting performance of an abrasive waterjet is affected by various parameters. In this study, rock cutting tests are conducted with different energy (i.e., water pressure, traverse speed, and abrasive feed rate), geometry (i.e., standoff distance), and material parameters [i.e., uniaxial compressive strength (UCS)]. In particular, experimental tests are carried out at a long standoff distance (up to 60 cm) to consider field application. The effective parameters of the rock cutting process are identified based on the relationships between the cutting performance indices (depth, width, and volume) and parameters. In addition, the cutting efficiency is analyzed with effective parameters as well as different pump types and the number of cutting passes considering the concept of kinetic jet energy. Efficiency analysis reveals that the cutting depth efficiency tends to increase with an increase in the water pressure and traverse speed and with a decrease in the standoff distance and UCS. Cutting volume efficiency strongly depends on standoff distance. High efficiency of cutting volume is obtained at a long standoff distance regardless of the pump type. The efficiency analysis provides a realistic way to optimize parameters for abrasive waterjet rock excavation.     

板峪口组大理岩中的变质流体

山西五台山区板峪口组大理岩的总体矿物组合为透闪石、金云母、白云石、方解石、微斜长石和石英,岩石变质时受缓冲作用控制。口泉主沟内绿帘石脉体中流体的X_(CO_2)为0.08,而围岩白云岩中X_(CO_2)大于0.4,同一地点脉体和围岩中变质溶液具有不同的X_(CO_2)说明溶液成分受缓冲作用控制。绿帘石脉体内溶液成分保持X_(CO_2)=0.8不变则说明溶液成分受渗滤作用控制。围岩内矿物组合为金云母、透闪石、方解石和白云石也说明溶液成分受渗滤作用控制。总的说来,本地区的变质溶液成分是缓冲作用加渗滤作用的综合结果。 本区变质时所通过的流体数量一般不超过岩石体积的1/4。当岩石内有单矿物脉体时,脉体内所通过的流体数量较高。绿帘石脉内所通过的流体大致相当于岩石体积(99％)。     

Effects of Rock Properties on Specific Cutting Energy in Linear Cutting of Sandstones by Picks

Summary. Specific cutting energy (SE) has been widely used to assess the rock cuttability for mechanical excavation purposes. Some prediction models were developed for SE through correlating rock properties with SE values. However, some of the textural and compositional rock parameters i.e. texture coefficient and feldspar, mafic, and felsic mineral contents were not considered. The present study is to investigate the effects of previously ignored rock parameters along with engineering rock properties on SE. Mineralogical and petrographic analyses, rock mechanics, and linear rock cutting tests were performed on sandstone samples taken from sites around Ankara, Turkey. Relationships between SE and rock properties were evaluated using bivariate correlation and linear regression analyses. The tests and subsequent analyses revealed that the texture coefficient and feldspar content of sandstones affected rock cuttability, evidenced by significant correlations between these parameters and SE at a 90% confidence level. Felsic and mafic mineral contents of sandstones did not exhibit any statistically significant correlation against SE. Cementation coefficient, effective porosity, and pore volume had good correlations against SE. Poisson’s ratio, Brazilian tensile strength, Shore scleroscope hardness, Schmidt hammer hardness, dry density, and point load strength index showed very strong linear correlations against SE at confidence levels of 95% and above, all of which were also found suitable to be used in predicting SE individually, depending on the results of regression analysis, ANOVA, Student’s t-tests, and R² values. Poisson’s ratio exhibited the highest correlation with SE and seemed to be the most reliable SE prediction tool in sandstones.     

国外业务水文的管理和投入机制

分析了美国等一些发达国家在水文站网、管理体制和经费投入等方面的情况及特点,以供我国有关部门参考。     

激光剥蚀等离子体质谱分析中激光剥蚀参数对信号响应的影响

探讨了激光剥蚀等离子体质谱固体微区分析中激光剥蚀参数对元素分析信号灵敏度及稳定性的影响。这些参数包括激光功率、脉冲频率、剥蚀孔经、散焦距离、剥蚀方式等。讨论了优化的激光剥蚀等离子体质谱信号采集及数据处理方式。在全质量范围内选用具有代表性的元素作为研究对象,建立了激光剥蚀的一般性特征规律和266nm紫外激光系统的最佳操作条件。在选定的激光剥蚀参数下,大多数被测元素的检出限为22.8~457ng/g,能够满足固体微区分析的要求。     

Influence of Geological Properties and Operational Parameters on TBM Muck Removal Performance for Yinsong Tunnel

Geotechnical and Geological Engineering - Operational parameters of a Tunnel Boring Machine (TBM) under different geological properties have significant influence on muck removal performance. To...     

切削齿型结构对金刚石钻头钻进性能影响的仿真分析

基于有限元分析软件ANSYS/LS-DYNA,建立了孕镶金刚石钻头的三维有限元模型,研究了钻头切削齿结构对钻进性能的影响并进行现场试验验证,提出了一种基于Image-Pro Plus的应力面积分布对比方式。结果表明：同心环齿型钻头在钻进初期沿旋转方向切削齿前缘出现应力集中现象,花齿型钻头未出现明显的应力集中;2种齿型钻头在钻进后期均会不同程度出现内外径边缘靠近水口部位应力集中现象,易导致钻头内外径部位变相磨损;花齿型钻头的钻进效率要优于同心环型钻头,但是钻进寿命有所下降。     

脉冲电镀工艺参数对镀层性能影响的研究

对脉冲电镀原理进行了分析，研究了脉冲电镀工艺参数对Ｎｉ镀层硬度、耐磨性的影响，得出了比较理想的工艺参数，为生产脉冲电镀镍基金刚石制品打下了基础。     

工程监测数据处理及监测对象安全性预测系统

以基坑监测为例利用计算机技术建立工程监测数据处理及安全性预测系统。系统共分二部分,一是信息化及规范化数据处理,即从监测的野外数据库出发通过关联建立一系列计算结果数据库,输出报表及相应的曲线图形;二是预测监测对象的安全性,即通过对各数据库中的特征值的提取,用模糊预测方法预测监测对象的安全性。     

水文信息处理系统研究

水文信息处理系统是在Windows环境下、用Visual Basic 6．0高级语言研制开发的智能水文资料整编软件，引用数据库存储信息，调用Excel输出整编成果。该软件实现了水位、流量、泥沙等要素关系线的自动生成和人工辅助定线，并完成全部整编计算工作，结束了我国水文资料电算整编工作中依靠手工定线整编的历史，解决了计算机定线、推流和成果输出一次完成的技术难题，真正实现了水文资料整编计算机化。     

宁夏降水型地质灾害气象条件等级预警系统

利用1982-2004年宁夏地质灾害与降水资料,在分析引发宁夏干旱区主要地质灾害的气象条件基础上,采用统计学方法分区建模,建立了宁夏降水型地质灾害潜势预报模型。依据该模型,在可视化高级编程语言DELPHl环境下,研究开发了一套自动化程度较高的降水型地质灾害气象条件等级预警系统;该系统可以通过网络,以协调一致的工作平台,将气象与地质等相关部门有机连接,实现了联合开展地质灾害预报及指导订正的业务流程。根据实时的雨情及降雨预报,依据所建的分区预报模型,对宁夏地质灾害的发生概率进行快速评价,实现对灾害发生的空间范围、强度及其分布概率的自动实时预警预报;通过人机交互订正,提供位图和GEOS（文本）2种格式的概率预报结论,同时实现了预报预警服务材料的自动化输出。2004,2005年的业务试运行表明,该预警系统基本能满足业务的需求,为新业务领域的拓展提供了技术支持。     

四川省石鑫大理石矿床特征及矿石工艺性质

石鑫大理石矿床是四川省优质大理石重要的生产基地。矿床主矿体赋存于下二叠统上部地层,主要岩性为结晶灰岩夹白色-浅灰-灰色大理岩。通过地质调查和样品测试分析,系统研究了矿床地质背景、矿床特征和矿石主要工艺性质,结果表明,各项指标达到或优于同类矿石国家标准。矿床开采技术条件较好,矿石加工技术性能优良,具备良好的开发前景。为矿区大理石的合理开采和综合利用提供了科学依据。     

RSM-08瞬态信号记录处理系统软件组成

为配合我所研制的RSM-08瞬态信号记录处理系统的使用,我们开发了若干软件。其中的某些软件引用了“数字信号分析”的一些理论与方法。本文对所实现的声波测时,声波测幅,应力应变分析,微机通讯等各项功能程序的内容,并着重对数据采集与分析程序的结构,算法及编程,作一介绍。     

The Software Content of RSM-08 Data Acquisition and Processing System

For the purpose of in conjunction with the usage of the RSM-08 instantaneous signal processor, which was developed and made by our institute, useful software has been designed. In which the theory and methods of “digital signal analysis” have been applied. To the realized program, such as time measuring and amplitude measuring of acoustic waves, stress-strain analysis and microcomputer communication etc. , have been introduced. Also special stress has been laid on the introduction of the structure, algorithm and programming of data acquisition and processing program.