探地雷达探测地下管线的研究     

战玉宝  张利民  尤春安 《岩土力学》2004,25(Z1):133-136

在大量的城市地下施工过程中,地下管线的保护越来越受到重视,掌握施工区地下管线的敷设又是确保地下管线安全的前提。本文结合工程实例介绍了探地雷达的基本原理以及资料处理方法,并分析了探地雷达在探测管线分布中的应用效果。  相似文献   

Factors affecting the groundwater chemistry in a highly urbanized coastal area in Hong Kong: an example from the Mid-Levels area   总被引：1，自引：0，他引：1  

Chi-man Leung  Jiu J. Jiao  John Malpas  Wing-tat Chan  Yan-xin Wang 《Environmental Geology》2005,48(4-5):480-495

Coastal areas of Hong Kong Island are one of the most extensively urbanized areas in the world. Groundwater samples in natural slopes and developed spaces in the regions centered by the Mid-Levels area, Hong Kong Island, were collected and analyzed to investigate the natural and anthropogenic processes affecting the groundwater chemistry. The results presented may be of value to other coastal areas in the world for the identification of possible groundwater contamination sources. Groundwater samples in the natural slopes were in low total dissolved solid (TDS) (<100 mg/l), indicating that the waters were in the early evolutionary stage. Using chloride as a normalizing factor, the “non-marine” components of different major ions in the samples were calculated. The correlation analysis indicated the occurrence of weathering of plagioclase feldspars in the natural slopes. However, the breakdown of biotite and K-feldspar seems to be limited by short groundwater residence time and high resistance to weathering. The high variety in hydrochemical facies may suggest the presence of extremely heterogeneous subsurface geological conditions. In the developed spaces, groundwater samples exhibited a high range of TDS (~100–5300 mg/l) and were mainly dominated by Na–Cl and Na–Ca–Cl water types. Besides water-rock interactions, the groundwater chemistry was significantly affected by leakage from service pipes and the dissolution of concrete materials. Some chemicals were used as signatures to identify the leakage from various service pipes. The area generally suffered from widespread, but small amount of leakages, and no obvious leakage was discovered. The strong correlations among major cations and chloride suggested that even a small amount of leakage from salty flushing water pipes can significantly affect the groundwater chemistry. Groundwater is found to be highly aggressive toward concrete as supported by three commonly used aggressiveness indices. Additional Ca²⁺ may be released to groundwater by corrosion of subsurface concrete materials such as building foundations and basements. The strength of those subsurface engineering structures may be weakened. Besides, excess Ca²⁺ may deposit in the dewatering systems in the area, which may affect their performance in lowering high water tables. The findings regarding leakage from service pipes will be useful for various government organizations such as the Water Supplies Department and Drainage Services Department. Discussion of the behavior of Ca²⁺ is instructional to foundation and slope dewatering designs in the area.  相似文献   

The Kharamai kimberlite field, Siberia: modification of the lithospheric mantle by the Siberian Trap event   总被引：1，自引：0，他引：1  

W.L. Griffin  L.M. Natapov  S.Y. O''Reilly  E. van Achterbergh  A.F. Cherenkova  V.G. Cherenkov 《Lithos》2005,81(1-4):167-187

The kimberlites of the Kharamai field intruded through the Siberian Traps shortly after their eruption in Permo-Triassic time. The composition and thermal state of the subcontinental lithospheric mantle (SCLM) beneath the Kharamai field in lower Triassic time have been reconstructed using major- and trace-element analyses of 345 Cr-pyrope garnet xenocrysts from six of the kimberlites, supplemented by a small suite of mantle-derived peridotite xenoliths. The data define a geotherm lying near a 38 mW/m² conductive model to a depth of ca 170 km, where the base of the depleted lithosphere is defined by a marked increase in melt-related metasomatism and by an inflected geotherm. Compared to the SCLM sampled by Devonian (pre-Trap) kimberlites in the same and adjacent terranes, the Kharamai SCLM in Triassic time was warmer and was cooling from a previous thermal high. It was also thinner than the SCLM beneath the Daldyn and Alakit kimberlite fields, and had been strongly metasomatised. The metasomatism lowered the mean Fo content of olivine (from ≥Fo₉₃ to Fo₉₂), greatly reduced the proportion of subcalcic harzburgites, and increased the proportion of fertile lherzolites, especially in the depth range of 80–130 km. The overall pattern of metasomatism is similar to that observed in the SCLM sampled by the Group I kimberlites of the SW Kaapvaal Craton, and inferred to be related to the Karoo thermal event. These observations suggest that events such as the eruption of the Karoo basalts and Siberian Traps change the composition of the SCLM, but do not necessarily destroy it, at distances of several hundred kilometres from the main eruption centres.  相似文献   

密排大口径排水管道顶管施工技术          下载免费PDF全文

绪新  杨生彬  王冬海 《探矿工程》2005,32(6):21-23

以天津市程林庄路二期改造——崂山道排水工程为例，介绍了密排大口径管道顶管施工方案的选择及工作坑支护施工、顶管施工过程中遇到的一些问题和技术难点，并给出了相应的处理措施。  相似文献   

Geology of the Gahcho Kué kimberlite pipes, NWT, Canada: root to diatreme magmatic transition zones     

C.M. Hetman  B.H. Scott Smith  J.L. Paul  F. Winter 《Lithos》2004,76(1-4):51-74

The Cambrian Gahcho Kué kimberlite cluster includes four main pipes that have been emplaced into the Archaean basement granitoids of the Slave Craton. Each of the steep-sided pipes were formed by the intrusion of several distinct phases of kimberlite in which the textures vary from hypabyssal kimberlite (HK) to diatreme-facies tuffisitic kimberlite breccia (TKB). The TKB displays many diagnostic features including abundant unaltered country rock xenoliths, pelletal lapilli, serpentinised olivines and a matrix composed of microlitic phlogopite and serpentine without carbonate. The HK contains common fresh olivine set in a groundmass composed of monticellite, phlogopite, perovskite, serpentine and carbonate. A number of separate phases of kimberlite display a magmatic textural gradation from TKB to HK, which is characterised by a decrease in the proportion of pelletal lapilli and country rock xenoliths and an increase in groundmass crystallinity, proportion of fresh olivine and the degree of xenolith digestion.

The pipe shapes and infills of the Gahcho Kué kimberlites are similar to those of the classic South African pipes, particularly those of the Kimberley area. Similar intrusive magmatic emplacement processes are proposed in which the diatreme-zone results from the degassing, after breakthrough, of the intruding magma column. The transition zones represent ‘frozen’ degassing fronts. The style of emplacement of the Gahcho Kué kimberlites is very different from that of many other pipes in Canada such as at Lac de Gras, Fort à la Corne or Attawapiskat.  相似文献   

金伯利岩和钾镁煌斑岩的磁性特征与航空磁测普查效果     

张昌达 《地质科技情报》1993,(Z1)

讨论了国内外用磁法普查金伯利岩的问题。与现代质子磁力仪的精度相适应,金伯利岩按磁性分为四类:实际无磁性的、弱磁性的、磁性的、强磁性的。大多数金伯利岩和钾镁煌斑岩是弱磁性的或磁性的。金伯利岩管的磁性无论在平面上和沿深度都是不均匀的。航空磁测普查金伯利岩和钾镁煌斑岩取得良好效果的3个条件中,最重要的是围岩磁性干扰水平低。  相似文献   

在金伯利岩中新发现的几种矿物及其意义   总被引：9，自引：1，他引：9       下载免费PDF全文

赵磊  路凤香  任迎新  郑建平  张宏福 《岩石矿物学杂志》1993,12(3):284-288

新近发现华北地台金伯利岩中存在自然铁、自然铜、自然锡、硅铁石、二硅铁矿、未命名的Si、Fe、Ti互化物及含铬黑镁铁钛矿等前人未曾报导过的矿物。据初步研究,它们与处于强还原环境的地幔深层流体有关。这些矿物的发现,首次为软流层中的流体交代作用提供了实物证据。  相似文献   

新疆库鲁克塔格某地角砾云母橄榄岩主要特征的初步研究     

黄存焕  刘树宝  宋松山 《新疆地质》1989,(2)

该角砾云母橄榄岩处于塔里木地台库鲁克塔格断隆.为晋宁期侵入岩,同位素年龄900Ma.围岩同位素年龄为2019—2150—2305Ma.该角砾云母橄榄岩与已知含金刚石金伯利岩在岩石、矿物成分.化学成分、结构、构造、微量元素地球化学特征、稀土元素丰度及分配模式,成岩温度.压力、氧逸度等方面均有惊人的一致性.  相似文献   

山东金伯利岩中新发现的柱红石亚族矿物──K-Cr柱红石──上地幔含大阳离子Cr、Ti、Fe氧化物矿物研究之二     

周湖云  陆琦 《矿物学报》1994,(3)

在山东蒙阴金伯利宕的副矿物蒙山矿中，首次发现了成分为柱红石类的新矿物相。对其成分进行探针分析，其一般晶体化学式可写为：A1.499～1.787B1.548～2,317C5.675～6.354O16。其中，A＝K、Ba、Na、La；B＝Cr、Fe、Mg、V；C＝Ti、Zr、Nb等，平均计算化学式为：（K1.256Ba0.241Na0.085La0.046）1.628（Cr1.817Fe0.321Mg0.085V0.093）1.816（Ti6.015Zr0.075Nb0.039）6.119O16．理想化学式K2Cr2Ti6O16；相当于Redledgeite（BaCr2Ti6O16）[1]的K端元，且与南非OrangeFree州StarMine及NewEland新发现的K－Ba－Vtitanates（钛酸盐）[2，3]具有成分上的可比性。为使柱红石亚族矿物的命名系统化，本文采用主要大阳离子（K、Ba）与变价元素（Fe、Cr、V）为端元组分的命名原则，将新种命名为K－Cr柱红石。根据国外资料对柱红石亚族矿物Redlcdgeite的成分修正[1,4]建议将其原中文译名“硅镁铝钛矿”[5,6]更正为“Ba－Cr柱红石”。新种与蒙阴近年来发现的沂蒙矿、蒙山矿一起，组成了含大阳离子及硅酸盐不相容元素的复杂钛铬铁氧化物组合，皆以K、Cr为特征，从而与南非以Ba为主，含V的这类矿物形成区域对比。  相似文献   

辽南瓦房店地区金伯利岩航磁垂向梯度异常特征及找矿意义     

贾志业 《地质与勘探》2023,59(3):617-626

航磁垂向梯度数据较航磁ΔT数据优势明显,可以有效识别地磁场的微弱变化。辽南瓦房店地区40%的金伯利岩体具有明显的梯度异常显示,可验证航磁垂向梯度技术在金刚石找矿中的有效性。本文通过分析瓦房店地区获取的大比例尺航磁垂向梯度资料,研究航磁垂向梯度异常特征与已知金伯利岩体产状的关系,发现岩体多位于NEE向孤立梯度异常中,岩体走向与异常走向基本一致,异常形态多表现为拉长的椭圆状,长轴走向多为NEE向,异常梯度值一般不大于150 nT/km,异常规模通常比地表出露范围大,对岩体的分布范围反映清晰。区内地质背景相似的NEE向航磁梯度异常对今后的金刚石矿勘查部署具有重要的指导意义,建议结合其他地质资料优选重点异常,布置大比例地面磁法、电法等地球物理方法查明引起异常的原因并评价其找矿前景。  相似文献