2012 Vol. 18, No. 1

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NUMERICAL SIMULATION OF IN-SITU STRESS FIELD IN THE AREA OF DEEP-BURIED AND LONGER TUNNEL IN NORTH TANSHAN, XINJIANG
MA Xiu-min, PENG Hua, JIANG Jing-jie, PENG Li-guo
2012, 18(1): 1-10.
Abstract (236) HTML (115) PDF (5334KB)(12)
Abstract:
In this paper, the measured in-situ stress data of the tunnel area, modern focal mechanism solutions of the North Tianshan region, regional geological structural data, as well as physical and mechanical parameters of rock mass were used as boundary and load conditions of the geological model. The three-dimensional numerical simulation was completed on stress field of the north Tianshan tunnel project area. And the rock mass stress distribution law in the whole project area, particular some important parts, was obtained. Stress data was provided for the tunnel project design. Based on the simulation results of the tunnel area stress field, the tunnel stability is analyzed.
DEVELOPMENT LAW AND PREDICTION OF THE LOWER-ORDER FAULTS IN THE WEST OF ZHENWU FAULT ZONE IN GAOYOU SAG
DAI Jun-sheng, ZHANG Ji-biao, FENG Jian-wei, TIAN Teng-fei, MAO Cheng-dong
2012, 18(1): 11-21.
Abstract (219) HTML (94) PDF (4034KB)(13)
Abstract:
On the basis of the application of ant tracking technology in the lower-order faults interpretation and determining the structural stress direction of Funing sedimentary period according to the main fault strike in Zhenwu fault zone, the method of numerical simulation of tectonic stress field was applied to simulate the distribution of structural stress in Funing sedimentary period, and then the development law of the lower-order faults both on the plane and profile were predicted from the perspective of stress, finally, the prediction result was compared to the structural analysis result. The results show that the fault traces are clear and intuitive in the attribute volume obtained by using the ant tracking technology to explain the lower-order faults, the application is more effective than some other seismic attribute technology such as the coherence and variance technique. The minimum principal stress direction was nearly NW333°-SE153° in the west of Zhenwu fault zone in Funing sedimentary period. The development of the lower-order faults were mainly controlled by the minimum principal stress and shear stress, the minimum principal stress control the advantage area of the fault development, the plane shear stress control the planar distribution, the fault were developed with nearly EW strikes in sinistral shear stress area and nearly NE strikes in dextral shear stress area, the profile shear stress control the fault tendency, the fault were developed with N and W tendency in sinistral shear stress area and S and E tendency in dextral shear stress area.
FEATURES OF PRESENT STRUCTURAL STRESS FIELD AND STRUCTURAL PATTERN IN HAIAN DEPRESSION, JIANGSU OILFIELD
WANG Zhang-qing, LI Hua-dong, DU Er-peng
2012, 18(1): 22-31.
Abstract (174) HTML (112) PDF (5177KB)(10)
Abstract:
In this paper, the present structural stress field of T40 reflection layer, the mechanic characteristics and structural active patterns of the second-level fault at the boundary of sub-depression and the third-and forth-level faults within sub-depression in Haian depression were analyzed. The direction of the present maximum principal stress is about NE 70°. The present maximum principal stress is about 50 MPa and the present minimum principal stress is about 30 MPa. By the present structural stress field finite element numerical modeling, we found that the second-level faults at the boundary of sub-depression are characteristic of tensile activity or tensile-shear activity which is in both clockwise and counter-clockwise, and that the activity features vary along the different part of a fault. The third-and forth-level faults within sub-depression have the same activity features as the second-level faults. In addition, some third-and forth-level faults also have compressive or compressive-shearing activity features.
CONTROLLING OF XIAKOU FAULT ON HYDROCARBON ACCUMULATION IN THE SOUTHERN PART OF HUIMIN DEPRESSION
WU Kong-you, ZHAO Zhong-xiang, Cui Shi-ling, LI Ji-yan
2012, 18(1): 32-41.
Abstract (133) HTML (85) PDF (4849KB)(11)
Abstract:
Xiakou fault plays an important role in controlling oil-gas accumulation in Huimin depression. By analyzing the lithologic association on two sides of fault, the mudstone-smearing and fault tightness index, Xiakou fault-sealing is studied quantitatively. The result shows that Xiakou fault sealing varies significantly in different locations. Based on the analysis of the fractured surface form of Xiakou fault, combined with the oil-gas migration simulation experiment, Xiakou fault is determined as the migration path in the south Huimin depression. It is found that Xiakou fault has two dominant migration channels, which contain most of the oil and gas. According to the relationship between faulting stage and hydrocarbon migration period of Xiakou fault, Xiakou fault accounts for the major oil and gas migration pathways in the south of Huimin depression, with the main hydrocarbon source rocks rowing in bulk. The complex closure property of Xiakou fault leads to the uneven oil-gas distribution in the south of Huimin depression.
DONGCHUAN MOVEMENT AND ITS INFLUENCE ON FOLDING STRUCTURES IN DONGCHUAN MINING DISTRICT
LIU Wei-ming, LIU Ji-shun, YIN Li-jun, YANG Li-gong, LIU Wen-heng, DOU Song
2012, 18(1): 42-51.
Abstract (148) HTML (72) PDF (2121KB)(10)
Abstract:
The various understandings about Dongchuan Movement were analyzed. Researches on characteristics of the strata in Kunyang Group, metamorphism, volcano-magma activities, and typical profiles as Tangdan, Luoxue and Tuobuka show that Dongchuan Movement is a large-scale tectonic movement. Dongchuan Movement is SN-trend compressional movement. In Dongchuan mining district, EW-trend fold structures formed in the lower Kunyang subgroup. These EW-trend fold structures were reformed and transformed by later Xiaoheijing Movement and Jinning Movement. The structural features became indistinct and complex. But after a careful study, the 10 larger fold structures were distinguished in Dongchuan mining district.
STUDY ON THE CONTROLLING STRUCTURE OF SALT DEPOSIT IN VIENTIANE PLAIN, LAOS
WANG Shao-hua, DU Jian-jun
2012, 18(1): 52-61.
Abstract (313) HTML (121) PDF (6119KB)(10)
Abstract:
The salt deposits in Vientiane Plain occurrence in Palaeocene Tagong Formation. The main Kalium-bearing minerals are carnallite and a little of sylvinite. During mineralization period, the Tagong Formation and salt deposits were controlled by NW-trending boundary faults and Tagong syncline. After mineralization period, the salt deposits were controlled by fold (salt syncline and salt anticline). The salt deposits formed broad and gentle fold under the horizontal stress. Inside syncline, deposition rate is relatively quickly and the thickness of clastic rocks upper salt seam is relatively large. On anticline, the thickness of clastic rocks upper salt seam is relatively thin. There are large density differences between salt deposits and clastic rocks, and the thickness of clastic rocks in the anticline is different from the one in syncline, so the salt deposits form differential loading. The salt deposits in syncline happened plastic flow towards anticline by larger loading. Thus the salt deposits in anticline become thicker, salt anticline form. The thickness of salt deposits in syncline becomes smaller. Thickness of the salt deposits in anticline is often great; its burial depth is shallow. The strata over anticline are often incomplete. With the salt anticline far development, the potash deposits pierce upper mudstone and expose oneself to relatively freshwater surroundings to suffer corrosion.
QUANTITATIVE CALCULATIONS OF ENVIRONMENTAL DOSE RATE AT DIFFERENT INFLUENCING FACTORS IN LUMINESCENCE DATING
ZHANG Ke-qi
2012, 18(1): 62-71.
Abstract (143) HTML (131) PDF (1370KB)(15)
Abstract:
The environmental dose rate (D) in luminescence dating can be influenced by water content, cosmic ray, factor a, radon escape, etc. A series of detailed quantitative calculations were applied to the sample A1 with given U, Th and K content for D values using different parameter values of water content, cosmic rays, factor a. The calculations show that the greatest influence is up to 50% with the changes of water content, and the influence from cosmic rays is up to 15%. The influence from factor a is relatively smaller because it usually is a given constant value. The radon escape will bring an error no more than 8%.
ELIMINATING THE DISTURBANCE OF VEGETATION INFORMATION BY SPECTRAL MIXTURE ANALYSIS BASED ON ANT COLONY ALGORITHM
XIA Hao-dong, XUE Yun, DENG Hui-juan, LIU Feng-jiao
2012, 18(1): 72-78.
Abstract (119) HTML (58) PDF (2514KB)(4)
Abstract:
In the research of extracting alteration information from remote sensing image, eliminating the disturbance of vegetation from image is important. In this paper, a spectral mixture analysis model is established based on ant colony algorithm, in order to eliminate the disturbance of vegetation. This model is applied to Jidi area in Huangnan City, Qinghai Province. Firstly, the ant-moving rule is defined. Secondly, the model of spectral mixture analysis based on ant colony algorithm is established. In the end, a new image without the disturbance of vegetation is plotted. Comparison of ETM image and result image shows that the disturbance of vegetation can be eliminated by the method.
GEOMORPHOLOGICAL FEATURES IN LUOYANGSHAN AREA, GUANGXI ZHUANG AUTONOMOUS REGION AND ITS RELATIONS WITH THE MAXIMUM EFFECTIVE MOMENT CRITERION
ZHANG Pei-quan, LI Bing-su
2012, 18(1): 79-90.
Abstract (137) HTML (99) PDF (6923KB)(5)
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In this paper, data about the intensity distribution in the meizoseismal area of Lingshan M=6¾ earthquake, geological structure, geomorphologic investigation and fission track dating were used to discuss the geomechanical environment in Lingshan Hill area. In the meizoseismal area, a T-shape Ⅸ+zone coupled NE Zhaixu Fault and NNW Sizhou Fault. Researches on tectonics and geomorphology showed uplifting of Luoyangshan Hill. The data of fission track dating supported this geomorphologic phenomenon. A new channel in front of Luoyangshan Hill (Gaodong) appeared in the west of the old channel. Distribution of earthquakes showed that a lot of low magnitude earthquakes concentratedly occurred in the southeast of the cross zone of NE Zhaixu and NNW Sizhou faults. All above were controlled by the Maximum Effective Moment Criterion (MEMC).
THE MODERATE-TERM PREDICTION FOR Mw 9.0 EARTHQUAKE IN JAPAN AND ITS SCIENTIFIC BACKGROUND
XU Dao-yi, DENG Zhi-hui, CHU Quan-Zhi, XU Hao-ming, TAO Jing-ling
2012, 18(1): 91-96.
Abstract (188) HTML (97) PDF (744KB)(2)
Abstract:
In this paper, the author summarized the moderate-term prediction about the super-great earthquake occurred in the sea off the east coast of Honshu, Japan on March 11, 2011, and discussed the predicting criteria. The predicted areas were defined to south Japan and other two areas. The predicted earthquake magnitude was 8.0 to 8.3. The moderate-term prediction was based on the tectonic system controlled by Qinhai-Tibet-Yunnan-Burma-Indonesian eta-type tectonic series. The comparison of prediction result to the occurrence of Mw 9.0 earthquake in Japan indicates that the prediction is basically correct.