A hybrid discrete-continuum approach to model hydro-mechanical behaviour of jointed rocks     

Lingli Wei  John A. Hudson 《Engineering Geology》1998,49(3-4):317-325

A hybrid discrete-continuum approach has been presented in this paper to simulate water flow in the near and far fields of deformable fractured rocks. In the near field, the discrete model is used; while in the far field, the equivalent continuum model is employed. The discrete element method (with the static relaxation algorithm) is used in the near field and the boundary integral equation method in the far field. Along the interface of these two domains, both mechanical and hydraulic compatibility conditions are satisfied. Fully coupled hydro-mechanical analysis can be conducted in the combined near and far fields. Application to a dam foundation problem has demonstrated the capability of the developed approach.  相似文献   

腾冲、长白山、五大连池新生代火山岩Sr、Nd、Pb同位素地球化学特征   总被引：5，自引：2，他引：3  

周真恒  姜朝松  李波 《地震研究》1998,21(4):379-387

概括了腾冲、长白山、五大连池新生代火山岩岩石学、岩石化学基本特征,探讨了Ｓｒ、Ｎｄ、Ｐｂ同位素地球化学特征和岩浆源区性质。腾冲火山岩为高钾钙碱性岩系,高８７Ｓｒ／８６Ｓｒ、高２０６Ｐｂ／２０４Ｐｂ、２０８Ｐｂ／２０４Ｐｂ、低１４３Ｎｄ／１４４Ｎｄ,岩浆源区为俯冲带再循环富集地幔。长白山火山岩为超钾钙碱性岩系,低Ｓｒ高８７Ｓｒ／８６Ｓｒ,εＮｄ为－２３—＋２９,Ｐｂ同位素组成变化不大,岩浆源区为俯冲带再循环地幔。五大连池火山岩为超钾碱性岩系,高８７Ｓｒ／８６Ｓｒ、低１４３Ｎｄ／１４４Ｎｄ和２０６Ｐｂ／２０４Ｐｂ、２０８Ｐｂ／２０４Ｐｂ,岩浆源区为地幔内部交代作用所产生的富集地幔。  相似文献   

Average Annual Temperature Changes in the Holocene in China     

BI Fuzhi  YUAN Youshen Peking University  Cheng Ze Yuan  Beijing 《《地质学报》英文版》1998,72(3):321-328

In 1876 Blytt proposed a post-glacial climatic classification, maintaining that the then temperature fluctuated 1- 2℃ higher or lower than that today. Lamb (1969) held that in Europe " the axis of the subtropical high pressure belt was generally displaced north by about 10° latitudes" during the Hypsithermal and that the temperature was three to six times higher than that in the postglacial period.In China, there appear relict beachrocks (living fossils) in tropical tidal zones from the Bohai Bay (40° N) to coastal areas in South China. Many relict tropical marine fossils were discovered, such as Ostrea gigas in Tianjin (which is larger than that found today in Hainan), Placuna placenta in Zhejiang and Spondylus sp. in Fujian. In Hebei, Henan and Zhejiang provinces and Guilin of Guangxi, such tropical fossil animals as Elephas maximus and Rhinoceros sp, were discovered, and in Hebei and Jiangsu provinces such fresh water fossils as Unio douglasiae were found. Their living species are still seen in So  相似文献   

Distribution Patterns of Pentacyclic TriterpenoidHydrocarbons in Low-Mature Source Rocksfrom Eastern China     

HOU Dujie  ZHANG Linye  WANG Tieguan Research Centre for Organic Geochemistry  Jianghan Petroleum Institute  Jingzhou  Hubei Applied Geochemistry Section  Dept. ofGeosciences  China University of Petroleum  Changping  Beijing Geochemistry Research Section  Shengli Petroleum Geological Sciences Institute  Shengli Petroleum Administration Bureau  Dongying  Shandong 《《地质学报》英文版》1998,72(4):399-408

Four typical distribution patterns of pentacyclic triterpenoid hydrocarbons (types A-D) are distinguished in the low-mature source rocks from eastern China. Type A has a relatively high content of pentacyclic triterpenes. It exists in immature sediments and the distribution and abundance of triterpenes vary with the maturity of the sediments. An unknown C30 triterpene (UCT2) has also been detected in very shallow sediments. This compound is very unstable and disappears rapidly with the increase of depth. Type B is characterized by a relatively high amount of 17α(H), 21β(H)-30-homohopane. This kind of distribution pattern is common in coals and terrestrial sediments of low maturity. Type C has a relatively high content of diahopane and neohopane series. The analysis shows that this distribution pattern may have an indirect relationship with the input of higher plants despite its microbial source. There are C30-unconfirmed triterpane (UCT2) and a relatively high content of C35 hopane in type D. The dist  相似文献   

Reform of Carbonate Rock Subsurface by Crustose Lichens and Its Environmental Significance   总被引：5，自引：0，他引：5  

CAO Jianhua  WANG FuxingInstitute of Karst Geology  Chinese Academy of Geological Sciences  Guilin  Guanxi Xiao Pinfang Liu Xinzhu 《《地质学报》英文版》1998,72(1):94-99

Crustose lichens are distributed extensively in karst areas in Southern China. They can be found on the surface of carbonate rocks. Through biophysical and biochemical processes, crustose lichens reform the subsurface of carbonate rocks and in the meanwhile change their physical and chemical properties: (1) the mechanical strength decreases by 17.04° on average (up to 33.2° ); (2) the chemical solution surface area increases from 28.26% to 75.36% (lichen microholes considered only); and (3) the water-holding capacity is greatly improved. Comparative field experiments between biokarst samples underneath crustose lichens and fresh rock samples with the same composition and texture show that the corrosional rate of carbonate rocks of the former is 1.264-1.643 times higher than that of the latter. Crustose lichens are considered as an activator of the surface corrosion of carbonate rocks.  相似文献   

遗传规划在岩石力学中的应用   总被引：1，自引：0，他引：1  

王战权  云庆夏 《物探化探计算技术》1998,20(4):306-311

本文探讨了遗传规划这一新的优化方法在岩石力学参数确定中的应用。由于影响岩石力学性能的各因素之间关系不明确,而遗传规划特别适用于各影响因素之间因果关系不明确的复杂非线性问题。它为预测岩石力学性能提供了一条新的技术途径。通过例子,说明该方法的实用性。  相似文献   

估算岩石断裂面粗糙度的一种分形模型   总被引：3，自引：0，他引：3  

徐志斌  谢和平 《煤田地质与勘探》1998,26(1):10-12,9

提出了一种更为简单的估算岩石断裂面粗糙度值的分形模型,可用来模拟岩石断裂面剖面线。断裂面愈粗糙,其分维值也愈大,并建立了分维值与ＪＲＣ值之间的经验方程。  相似文献   

塔里木盆地北部古生界密集段分布型式与海平面变化的关系   总被引：4，自引：1，他引：3  

樊太亮 《地球学报》1998,19(3):308-314

塔里木盆地北部震旦纪－古生代层序地层格架中,发育着６个可作为生油层的大型密集段或复合密集段。密集段在层序格架中有４种叠置型式,即进积组合,退积组合,加积组合和上超组合。不同的叠置型对应于不同的海平面变化过程。相应地,密集段的发育规模及时空展布有着明显的差别,其中,在退积层序组合和进积层序组合中,密集段垂向上相互叠置,侧向上彼此邻接,构成层数与厚度复杂多变的复合密集段,是盆地中的主力生油层。  相似文献   

论德尔尼黄铁矿型铜钴矿床的地质特征及其与塞浦路斯铜矿的区别   总被引：2，自引：0，他引：2  

段国莲 《化工矿产地质》1998,(4)

通过对德尔尼铜钴矿床与塞浦路斯铜矿的对比,进一步明确了德尔尼铜钴矿床为与印支期黑云花岗岩有成因联系的岩浆热液矿床。矿区的超基性岩或超基性火山角砾岩都是不含矿的,与矿床无成因联系;底辟上升侵位也不存在。将德尔尼铜钴矿床作为火山岩块状硫化物矿床系列中的最基性端员缺乏依据。  相似文献   

青海某地第三纪红色碎屑岩层中发现金矿物   总被引：1，自引：0，他引：1  

马生明  王俊祥 《黄金地质》1998,4(2):58-61

第三纪红色碎屑岩层在青海分布广泛。长期以来,由于它特征的地理地质条件,在这一层位中寻找金属矿床的工作不受重视,至今未见在该层位中发现金属矿（化）的文献报导。但在一些地区的第三纪红色碎屑岩层中有化探金异常。在某地Ａｕ异常浓集区所进行的化探查证工作初步揭示了Ａｕ异常的形成是由于次生富集作用引起的,并在水系重砂样品中首次发现金矿物颗粒,从而为地质工作者重新认识这个金属矿的“不毛之地”提供了确凿证据。  相似文献