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61.
《China Geology》2020,3(2):339-344
Considering the geological hazards attributed to the highway slope, using a common simple model cannot accurately assess the stability of the slope. First, principal component analysis (PCA) was conducted to extract the principal components of six factors (namely, bulk density, cohesion, internal friction angle, slope angle, slope height, and pore water pressure ratio) affecting the slope stability. Second, four principal components were adopted as input variables of the support vector machine (SVM) model optimized by genetic algorithm (GA). The output variable was slope stability. Lastly, the assessing model of highway slope stability based on PCA-GA-SVM is established. The maximal absolute error of the model is 0.0921 and the maximal relative error is 9.21% by comparing the assessment value and the practical value of the test sample. The above studies are conducive to enrich the assessing model of highway slope stability and provide some reference for highway slope engineering treatment. 相似文献
62.
《China Geology》2020,3(4):575-590
The sequence stratigraphic framework of Shanxi Formation in the northeast Zhoukou Depression was established based on detailed sequence stratigraphical and sedimentological analysis by utilizing the logging and core data of six wells drilled in the eastern tectonic unit of Zhoukou Depression. It was divided into three third-order sequences, namely SQs1, SQs2, and SQs3 from bottom to top. Each sequence can be divided into a transgressive system tract (TST) and a highstand system tract (HST). Furthermore, four sequence boundaries and three maximum flooding surfaces were identified, and they are the bottom interface SBs and maximum flooding surface mfss1 of SQs1, the bottom interface SBs1 and maximum flooding surface mfss2 of SQs2, the bottom interface SBs3 and maximum flooding surface mfss3 of SQs3, and the top interface SBx from bottom to top. Carbonate tidal flat –clastic tidal flat sedimentary system developed in Shanxi Formation in the northeast Zhoukou Depression (also referred to as the study area) under the control of regression. Meanwhile, four sedimentary microfacies were identified in the sedimentary system, which are lime-mud flats, sand flats, mixed flats, and mud flats. The transgression in the study area occurred from the southeast to the northwest. Therefore, the northwestern part is the seaward side, and the southeastern part is the landward side. As revealed by relevant drilling data, SQs1 of the Shanxi Formation is characterized by the development of limestone and carbonaceous mudstone, with limestone, dark mudstone, and carbonaceous mudstone mainly developing. Meanwhile, lime-mud flats were mainly deposited in it. During the periods of SQs2 and SQs3, the sedimentary environment of the study area changed from the carbonate tidal flats to clastic tidal flats as the coastline migrated towards the sea. In these periods, sand flats mainly developed near the maximum flooding surfaces and were relatively continuous in the eastern and southern parts of the transgressive system tract; mixed flats were relatively continuous in the western and northern parts of the transgressive system tract as well as the eastern and southern parts of the highstand system tract; mud flats widely developed in the highstand system tract. Peat flats mainly developed in the period of HSTs2, with coal seams relatively developing in the southeastern part of the study area as revealed by drilling data. The peat flats in SQs2 are favorable hydrocarbon source layers, the lime-mud flats in SQs1 and sand flats formed in the transgression periods of SQs2 and SQs3 constitute favorable hydrocarbon reservoirs, and the mud flats form in the transgressions periods serve as favorable cap rocks. Therefore, the study area features a reservoir-cap assemblage for self-generating and self-storing of hydrocarbon, and the southeastern part of the study area can be taken as a favorable exploration area. 相似文献
63.
《China Geology》2020,3(2):230-246
The Dongyang gold deposit is a newly discovered epithermal deposit in Fujian Province, Southeast China, along the Circum-Pacific metallogenic belt. Herewith, the authors present mineralogical, scanning electron microscope, and laser ablation inductively coupled clasma mass spectrometry analysis to reveal the relations between Au and Te, As, S, Fe, etc., and discuss the gold precipitation process. The pyrites in this deposit are Fe-deficient, and are enriched in Te and As. The authors infer that As was mainly in form of As-complexes, and Te-Au-Ag inclusions/solid solution also exsits in the Py I. Along with the depletion of Te and As, they were less active chemically in the Py II, and Au may be incorporated into As-rich and Fe-deficient surface sites by chemisorption onto As-rich growth surfaces. Because of the incorporation of new fluid, Te and As became the most active chemically in the Py III, which was the main elements precipitation stage, and As dominantly substituted for S in the lattice of pyrite, due to the more reducing condition. The authors propose Au was in form of invisible gold, and the incorporation of gold can be considered as post-pyrite event, while the Au-bearing minerals were result of post incorporation of gold in arsenian pyrite. 相似文献
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Johan Spross Lars Olsson Håkan Stille 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2018,12(3):183-189
The Swedish Geotechnical Society has adopted a general methodology for risk management in geotechnical engineering projects to reduce the costs related to negative outcomes of geotechnical risks. This technical note highlights the main features of the methodology and strives to inspire the international geotechnical community to apply sensible risk management methods. In the authors’ opinion, a successful geotechnical risk management needs to be structured, be tailored to the project, and permeate the engineers’ everyday work. Then, sufficient quality can be achieved in the project with larger probability. 相似文献
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自从20世纪80年代PDC复合片研发成功以来,PDC钻头由于其钻进性能强和耐磨性能好,在世界许多国家的石油钻井和地质勘探中得到了广泛应用,取得了很好的效果。但是,如何进一步提高其在钻探工程中的技术经济指标是一个很迫切的问题。俄罗斯博士Скоромных В. В.教授等对此进行多年研究,提出了稳态破碎岩石方式的思想,即在轴载和扭矩切力形成的合力R与切削面成垂直角度条件下,切入深度h不变时形成的一种碎岩方式。并在此基础上提出了一些设计PDC钻头方面的建议。 相似文献
70.
针对石油钻井工程与矿产地质钻探工程中使用的部分专业术语在理解和应用上存在的差异进行梳理,为了方便各项技术工作的融合、沟通交流和资料的收集与验收,希望相关专业术语在定义和使用上进一步规范和统一,以便于对今后非常规油气地质岩心钻探工作的开展能有所帮助。 相似文献