夏季新建码头混凝土面层裂缝的原因分析     

张大鹏  李明 《海岸工程》2009,28(1):27-29

针对夏季施工的码头混凝土面层产生的连续裂缝,分析了裂缝产生的原因,并提出以后的施工作业中应注意的问题,以防止类似现象再次发生。  相似文献   

Pressure dependence of permeability: a model for cracked rocks     

P. Gavrilenko  Y. Gueguen 《Geophysical Journal International》1989,98(1):159-172

  相似文献   

花山谜窟景区2号、35号洞窟稳定性分析研究     

王宏伟  孙风贤 《上海国土资源》2007,(4):14-20

花山谜窟景区2号、35号洞窟位于安徽省黄山市的新安江畔,其所处的地质环境条件复杂,洞窟区岩石力学的强度差异大,洞窟顶板裂隙较发育,顶板渗水较严重,加之,洞窟内部分支撑柱的间距过大,洞窟开发过程中忽略了对洞窟地质环境的保护等,引发了片状剥落、块状坠落、新生裂缝(顶板及支撑柱)三类洞窟变形失稳问题,这三类问题不仅破坏了洞窟内的地质环境,同时,也给洞窟的科学保护带来了隐患。为此,对洞窟稳定性问题产生的条件进行分析研究,并在此基础上提出了加强洞窟地质环境保护的对策。  相似文献   

Jurassic septarian concretions from NW Scotland record interdependent bacterial, physical and chemical processes of marine mudrock diagenesis   总被引：3，自引：0，他引：3  

JAMES P. HENDRY  MICHAEL J. PEARSON†  NIGEL H. TREWIN‡  ANTHONY E. FALLICK§ 《Sedimentology》2006,53(3):537-565

Septarian concretions in the Staffin Shales Formation (Kimmeridgian, Isle of Skye) allow controls on concretion rheology and septarian cracking to be investigated. Stratabound concretions consist of anhedral ferroan calcite microspar enclosing clay and minor pyrite. Intergranular volumes range from 77% to 88%, and calcite δ¹³C and δ¹⁸O values in most concretion bodies range from ?10·0‰ to ?17·3‰ and +0·3‰ to ?0·6‰ respectively, consistent with rapid and pervasive cementation in marine pore fluids. Septarian rupture occurred during incipient cementation, with a sediment volume reduction of up to 43%. Crack‐lining brown fibrous calcite records pore fluid re‐oxygenation during a depositional hiatus, followed by increasing Fe content and δ¹³C related to bacterial methanogenesis. Brown colouration results from an included gel‐like polar organic fraction that probably represents bacterially degraded biomass. A new hypothesis for concretion growth and septarian cracking argues that quasi‐rigid ‘proto‐concretions’ formed via binding of flocculated clays by bacterial extracellular polysaccharide substances (EPS). This provided rheological and chemical conditions for tensional failure, subcritical crack growth, volume contraction, calcite nucleation, and incorporation of degraded products into crack‐lining cements. Bacterial decay of EPS and syneresis of host muds provided internal stresses to initiate rupture at shallow burial. Development of septarian (shrinkage) cracks in muds is envisaged to require pervasive in situ bacterial colonization, and to depend on rates of carbonate precipitation versus EPS degradation and syneresis. Subsequent modification of septarian concretions included envelopment by siderite and calcite microspar, hydraulic fracturing associated with Cretaceous shallow burial or Palaeogene uplift; and cementation by strongly ferroan, yellow sparry calcite that records meteoric water invasion of the host mudrocks. An abundance of fatty acids in these spars indicates aqueous transport of organic breakdown products, and δ¹³C data suggest a predominantly methanogenic bicarbonate source. However, the wide δ¹⁸O range for petrographically identical cement (?1·3‰ to ?15·6‰) is difficult to explain.  相似文献   

水晶中裂隙成因及其鉴定意义     

迟广成赵爱林  林维峰 《岩矿测试》2005,24(4):317-318

从结晶学入手,分析了天然水晶中愈合裂隙的成因和合成水晶形成愈合裂隙的可能性,比较了天然水晶和合成水晶裂隙的特征,认为愈合裂隙可以作为天然水晶鉴定的标志型特征。  相似文献   

Scattering of elastic waves by a 2-D crack using the Indirect Boundary Element Method (IBEM)   总被引：1，自引：0，他引：1  

Ursula Iturrarán-Viveros  Rossana Vai  Francisco J. Sánchez-Sesma 《Geophysical Journal International》2005,162(3):927-934

  相似文献   

采场工作面顶板突水的渗流场分析   总被引：1，自引：0，他引：1  

张后全  杨天鸿  赵德深  李连崇  唐春安 《煤田地质与勘探》2004,32(5):17-20

应用东北大学岩石破裂与失稳研究中心(CRISR)自主开发的F-RFPA2D渗流与应力耦合分析系统,对煤层顶板随着开采的逐步进行,采动裂隙逐渐向上发展并最终与含水层连通,进而发生顶板突水的全过程进行了数值模拟,直观地显示了煤层顶板的变形、破坏过程以及渗流场在整个岩体的运移过程及其突水前后渗流场的变化情况,从而较好地揭示了顶板突水过程。   相似文献   

Effects of lithology and land use on storm run-off in east luxembourg     

Martin R. Hendriks 《水文研究》1993,7(2):213-226

For a large part of the year, the forested catchments in the Keuper formation of east Luxembourg produce more direct run-off on a storm basis than paired cultivated catchments. The occurrence of shrinkage cracks, their pronounced opening and closing, and the occurrence of natural pipes in the forested environment play a major role in explaining this phenomenon. The effect of land use on storm run-off is studied in relation to that found for lithology in the same area.  相似文献   

Detecting Voronoi (area-of-influence) polygons     

David G. Evans  Steven M. Jones 《Mathematical Geology》1987,19(6):523-537

Voronoi, or area-of-influence, polygons are convex, space-filling polygons constructed around a set of points (Voronoi centers) such that each polygon contains all points closer to its Voronoi center than to the center of any other polygon. The relationship of Voronoi centers to edges of Voronoi polygons is used to test whether any convex tessellation consists of Voronoi polygons. This test amounts to finding Voronoi centers that best fit the given tessellation. Voronoi centers are found by solving two systems of linear equations. These equations represent (1) conditions on the slope of polygon edges relative to the slope of lines through Voronoi centers, and (2) conditions on the distance from edges to Voronoi centers. Least squares and constrained least-squares solutions are used to solve the two systems. Different methods of solution can provide insight as to how a tessellation varies from Voronoi polygons. A goodness-of-fit statistic is derived and examined by testing randomly generated convex tessellations. Some polygonal ice cracks provide an example of naturally occurring polygons that are approximated closely by Voronoi polygons.  相似文献   

Wave propagation through fluid-filled inclusions of various shapes: interpretation of extensive-dilatancy anisotropy   总被引：1，自引：0，他引：1  

Stuart Crampin 《Geophysical Journal International》1991,104(3):611-623

  相似文献