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Ling M.-X.,CAS Guangzhou Institute of Geochemistry | Ling M.-X.,Isotope Laboratory | Li Y.,China Petroleum Pipeline Engineering Corporation | Ding X.,CAS Guangzhou Institute of Geochemistry | And 5 more authors.
Journal of Geology | Year: 2013

The destruction of the North China Craton (NCC) mainly occurred in the Cretaceous and has been attributed to a "top-down" rapid delamination, "bottom-up" long-term thermal/chemical erosions, or hydration by subductionreleased fluids. On the basis of the distribution of one Jurassic and two Early Cretaceous adakite belts and the drifting history of the paleo-Pacific Plate, we propose that three ridge subduction events dominated the large-scale decratonization in the NCC. Both physical erosion and magmatism induced by ridge subduction contributed to the destruction of the NCC; the last ridge subduction, at 130±5 Ma, was the key driving force in the final destruction. We present mineralogical, geochemical, and isotopic data in support of the ridge subduction model: flat subduction of a spreading ridge resulted in stronger physical erosion on the thick lithosphere mantle of the NCC. Consequently, slab melting occurred during ridge subduction, forming adakites with mantle Mg isotope compositions, followed by A-type granites as a result of asthenosphere upwelling. Delaminated lower continental crust was also partially melted after reacting with hydrous magmas, as indicated by eclogite xenoliths, resulting in a zircon age spectrum similar to that of the NCC and some adakitic samples with chemical characteristics similar to those of the Dabie adakites. The final decratonization was triggered by the last ridge subduction, with both physical erosion (flat subduction) and thermal erosion (adakitic and A-type magmatisms). Given that ridge subduction has occurred throughout Earth's history, the associated decratonization processes are presumably a common phenomenon that modified the chemical compositions of the continental crust. © 2013 by The University of Chicago.

Zhang Y.,University of Science and Technology Beijing | Pang X.,University of Science and Technology Beijing | Qu S.,University of Science and Technology Beijing | Li X.,China Petroleum Pipeline Engineering Corporation | And 2 more authors.
International Journal of Greenhouse Gas Control | Year: 2011

Corrosion experiments were performed with X65 pipeline steel under static supercritical carbon dioxide (SC CO2) conditions at 50, 80, 110 and 130°C. The morphology, structure, chemical composition and fracture toughness of CO2 corrosion scales formed on the surface of X65 pipeline steel at various temperatures were investigated by means of Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDS). The corrosion rates were measured using weight-loss method. The fracture toughness of CO2 corrosion scale formed at different temperatures was investigated by means of nanoindentation and Vicker's indentation on a polished cross-section of the CO2 corrosion scale. The results showed that the corrosion rates increased from 50°C to 80°C and then decreased from 80°C to 130°C. As the temperature increased, the fracture toughness of CO2 corrosion scale first decreased and then increased, and the lowest fracture toughness was found at 80°C. The corrosion rate (CR) has a quantitative relationship with the fracture toughness (KIC)CR=(3.25/KIC3/2)-0.908. © 2011 Elsevier Ltd.

Zhang Y.,University of Science and Technology Beijing | Pang X.,University of Science and Technology Beijing | Qu S.,University of Science and Technology Beijing | Li X.,China Petroleum Pipeline Engineering Corporation | And 2 more authors.
Corrosion Science | Year: 2012

The corrosion behaviour of X65 pipeline steel at various temperatures for different immersion time under low CO 2 partial pressure and supercritical CO 2 condition were investigated by weight loss measurements and surface analysis techniques. By comparing the characteristics of CO 2 corrosion product scale formed under experimental conditions and the variation rule of corrosion rate with temperature, the CO 2 corrosion mechanism under low partial pressure and supercritical condition was studied. To explain the big difference of corrosion rate between low CO 2 partial pressure and supercritical CO 2 condition, thermodynamic calculation of the solubility of CO 2 in H 2O were discussed. © 2012 Elsevier Ltd.

Gao F.-P.,CAS Institute of Mechanics | Yan S.-M.,CAS Institute of Mechanics | Yan S.-M.,China Petroleum Pipeline Engineering Corporation | Yang B.,CAS Institute of Mechanics | Luo C.-C.,University of Western Australia
Ocean Engineering | Year: 2011

The steady flow-induced instability of a partially embedded pipeline involves a complex process of pipesoil interaction. In accordance with the hydrodynamic loading and the dimensionless analyses, a series of pipesoil interaction tests have been conducted with an updated pipesoil interaction facility including a loaddisplacement synchronous measurement system, to reveal the underlying pipesoil interaction mechanism. The effects of pipe surface roughness, end-constraint and initial embedment are investigated, respectively. The values of lateral-soil-resistance coefficient for the rough pipes are bigger than those for the smooth pipes. For a fixed value of non-dimensional submerged weight, the values of lateral-soil-resistance coefficient for the anti-rolling pipes are much larger than those for the freely laid pipes. The effects of initial embedment on the ultimate soil resistance get less with the decrease of the submerged weight of the pipe. A comparison is made between the results of the present mechanical-actuator tests and those of the previous water-flume tests, indicating that those results are quite comparable. For the equivalent level of dimensionless submerged weight, the directly laid pipe in currents has higher lateral stability than in waves. © 2010 Elsevier Ltd. All rights reserved.

Wang H.,China Petroleum Pipeline Engineering Corporation
ICPTT 2013: Trenchless Technology - The Best Choice for Underground Pipeline Construction and Renewal, Proceedings of the International Conference on Pipelines and Trenchless Technology | Year: 2013

In connection with the types of geo-hazards constituted by karst effect to pipeline ,this paper elaborates the evaluating calculation methods for the stability of karst top slaband estimation formula for the safe distance between karst cave and pipeline. Put forward are the protection measures for pipeline in karst area, including diverting of karst surface water, interception and blocking of water in pipeline trench, over-crossing form of mouth of karst cave and reinforcement of karst cave. © ASCE 2013.

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