What Causes Cracks in Rock Blasting?

In blasting, a few or many cracks are driven from the borehole into the rock. But what causes the cracks? The most common theory of breakage consists of two stages; first the shock wave causes radial cracks to form around the hole then the gases penetrate into the cracks, and widen them and make them longer. Another theory presented by Brinkmann suggests that the back damage is primarily controlled by shock and that the gas penetration is the mechanism controlling breakout of the burden. He did his experimental work using blasthole liners. Recent research at SveBeFo has examined this matter further. In a quarry a number of benching holes have been blasted simultaneously. In some of these holes tubular Swellex bolts were inflated and decoupled charges put inside the tubes without stemming. Other holes were identically charged but without the lining. Finally some holes were also stemmed. After blasting the cracks in the remaining rock were studied. There was no difference in crack lengths between holes charged normally (no stemming) and holes where the charges were inside the bolts. On the other hand when stemming was used, the crack lengths increased for some explosives but remained the same for an emulsion explosive. In another set up blasted granite blocks were charged in the same way as above. Then we could also measure the bore hole pressure. The pressure gauge consists of a small carbon resistor inside a steel cylinder. It is called LHM (Location-fixed Hydrodynamic Measuring cup) and is placed at the bottom of the hole. A smaller exit hole from the bottom is drilled for the cables. The paper presents the technique and the results obtained from both the quarry blasting and the blasting of the blocks.     

堡子梁隧道顶部古滑坡地质灾害整治工艺方法

堡子梁隧道顶部古滑坡地质灾害整采用迈式主浆锚杆、迈式注浆泵以及相应的施工工艺和深孔压浆技术，获得了较好的工程治理效果。     

非均匀介质中微侧向测井仪器的三维有限元数值分析

在这篇文章中，分析了一个具有井眼的非均匀介质中似稳电流场的边值问题。采用了三维有限元的直接解法求解三维似稳电流场；给出了微侧向测井仪器的电极表面电流分布、假几何因子以及８英寸井眼的泥饼校正曲线；求出了在具有倾斜地层条件下，微侧向测井仪器对界面的响应。数值结果与发表的文献非常吻合，从而证明了这种方法的正确性。因此，它为新的仪器研制和微侧向测井解释提供了可靠的数据和理论依据。     

Relationship between coral growth rate and sea surface temperature in the northern part of South China Sea during the past 100 a

To research the relationship between coral growth rate and sea surface temperatnre (T_ss), 5 cores of livingPorites lutea were collected from the Xisha Islands and the southern Hainan Island waters and measured. The results of the study show that there is an obviously positive correlation between the coral growth rates and theTss records from the northern part of South China Sea. The annual growth rates of the five samples ofPorites lutea during the past 100 a are in the range of 7—15 mm/a, and their mean value is 11 mm/a. The correlation coefficients between the coral growth rates and the T_ss records from the waters during 1961—1993 are in the range of 0.77—0.89. As a result, a thermometer of the coral growth rate is established. A hindcasting T_ss, in the waters from 1993 to 1961 has been obtained with an error of about 0.12—0.17°C. Based upon the calculated result, the rising rate of T_ss in the northern part of South China Sea during the past 100 a is 0.20°C. which is higher than that of the air temperature in China (0.09°C/100 a), but lower than that of the global temperature and that of T_ss in the tropical western Pacific Ocean. Project supported by the National Nutural Science Foundation of China and the Multidesciplinary Oceanographic Expedition Team of Chinese Academy of Sciences to the Nansha Islands.     

溃屈型滑坡滑面强度特征及在稳定性预测中的意义——李家峡水电站初期蓄水水库滑坡预测成功原因分析

溃屈型滑坡由于滑动破坏方式的不同，滑面的物质组成有明显的差异。按照物质组成的特征对滑面强度参数进行分段试验、取值，是作好此类滑坡稳定性预测的重要环节。以李家峡水库Ⅱ号滑坡为研究实例，介绍了作者们在滑坡预测成功方面所取得的研究成果。     

广西拉么铜锌矿床矿物学特征及其地质意义

广西拉么铜锌矿床矿物学特征及其地质意义李明琴税哲夫聂爱国张杰（贵州工业大学资源工程系，贵阳５５０００３）关键词黄铜矿闪锌矿矿物学特征铜锌矿床广西拉么广西拉么铜锌矿床位于黔桂边界广西南丹县境内，在大地构造上位于江南地轴西南缘、南丹河池轴缘凹陷带中。矿床...     

地球动力学过程中的波动现象及其在地震预报中的应用

讨论了地球内部的波动现象与构造及地震间的关系。引进了４类广义构造波。它们是：表现为地球不同年代的综合构造运动结果的超长周期构造波；由地震活动性迁移，即所谓地震活动波所反映的长周期（不同类型与不同速度的，周期从几年到几十年）构造波；由地震前兆三阶段发展过程反映出的中等周期（从几月到几年）构造波；以及由地下水位、地倾斜、重力、地震波、电磁辐射、地声等的变化所记录的短周期（从几分到几天）构造波。地震活动波又有３类，可分别用广义瑞利型构造波、广义洛夫型构造波及广义导波型构造波来解释。最后，研讨了地球内部波动现象在地震研究中的应用，包括它们在地震危险性分析与地震区划、地震预报以及地震成因研究中的应用。     

用重力压密原理评价大型滑坡滑面强度参数

大型滑坡泥质滑动面强度参数的正确选取，是作好稳定性评价的重要环节。本文从滑坡形成初期时滑带土的结构特征，滑面的应力状态出发，提出了用重力压密原理研究滑带土的物理力学性质，并用实例介绍了研究步骤和评价效果，为大型滑坡动面强度参数评价提出了新的途径。     

“一带一路”沿线国家投资悖论的形成机理研究

投资与贸易合作是“一带一路”倡议实施的重点。投资者往往会选择低风险且具有高收益潜力的国家或地区进行高投资,然而中国企业对“一带一路”沿线国家的投资却存在高风险与高投资并存的投资悖论现象。本文遴选2013—2018年“一带一路”沿线吸纳中国对外直接投资金额较高且存在较高投资风险的国家,解析这些国家的时空特点,探究投资悖论的形成机理。研究发现：（1）从空间视角看,投资悖论国家大多数为中国的周边邻国。从“一带一路”的空间走向看,海上丝绸之路沿线国家分布较多;从分布密度看,东南亚地区是投资悖论国家分布的集中区。（2）从时间视角看,高风险高投资在时间上具有延续性,6年间有13个国家出现两次以上的投资悖论现象。按投资悖论出现的频次,将“一带一路”沿线国家分为高频国家、中频国家和低频国家。（3）从形成机理看,地缘区位、能源资源、地缘政治、地缘经济和人文社会这五个因素分别从不同的方面作用于投资悖论的产生。     

西北干旱区乡村性评价及驱动机制研究——以甘肃武威为例

基于武威市1949~2013年65 a的社会经济统计数据,以县域为基本单元构建乡村性指标体系,通过测算各县区乡村性指数和分异指数来分析乡村性的时间演变和空间分异,并从社会经济和技术经济两个维度探讨了乡村性演变的影响因素。结果表明：① 1949~2013年间武威市各县区乡村性指数总体呈减弱趋势,但减弱幅度和速度存在差异。② 各县区乡村性分异指数呈波动增长趋势,2000年以后乡村性分异指数急剧增长,表明各县区乡村性差异越来越大。③ 社会经济和技术经济是影响乡村性变动的两大动因,各因素的发展致使城乡差距缩小、乡村性水平减弱、城乡一体化发展趋势明显。