2009 Vol. 15, No. 3

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THE MAXIMUM-EFFECTIVE-MOMENT CRITERION DEVELOPING IN PRACTICE
ZHENG Ya-dong, ZHANG Jin-jiang, WANG Tao
2009, 15(3): 209-217.
Abstract (172) HTML (96) PDF (536KB)(19)
Abstract:
Since the Maximum-Effective-Moment Criterion was published, it has been obtaining evidence in nature and the laboratory and supports from geologists home and abroad. Behavior of rock during deformation depends on mechanical property itself, structure levels (including such factors as temperature, pressure, fluid) and strain rate. The lozenge features and conjugate kink zones with obtuse angles in the contractional direction at shallow levels are consistent with the criterion and suggested as deformation at low strain rates and conform that the strain rate plays a more important role than the structure level in deformation. Coexistence of brittle and ductile features implies a tectonic evolution with alternation of high and low strain rates.
ANALYSES ON GRAIN SHAPE AND LIMITED RESPONSE USING GIS
LI Bo, ZHANG Ting-shan, WANG Zhan-lei, DONG Yin-lei
2009, 15(3): 218-225.
Abstract (117) HTML (60) PDF (364KB)(7)
Abstract:
By geographical database management and space objects overlay analysis of GIS, this article makes a use of GIS in the analyses on grain shape and limited response of rocks, bringing about an approach of defining and getting grain parameters of the shape and attributes in GIS environment. In the analysis on particle limited response, two methods were used: TFry and ASPAS. Taking the thin sections of clastic rock from Dafeng-Xinghua exploration blocks in north Jiangsu Basin as research objects, an analysis has been made on the polygon shape and crystal plastic property of grains after vectorization, providing a powerful method for structural geology analysis and application.
INFLUENECE OF FAULT CRUSH BELTS ON THE STABILITY OF TUNNEL ROCK
LUO Li-rui, LIU Zhi-gang
2009, 15(3): 226-232.
Abstract (263) HTML (107) PDF (184KB)(20)
Abstract:
The stability of tunnel rock is vital to tunnel construction. By applying the compounding of tectonic systems and tectonic evolution of geomechanics, an analysis has been made on features of single fault crush belts, compound fault crush belts, conjoining fault crush belts, and their influence on stability of tunnel rock, which were confirmed in the field cases of Xiamen sub-sea tunnel. The results show that conjoining fault crush belts and compound fault crush belts can easily lead to unstability of rock, and other factors of faults, such asweathering and the angle between faults strike and tunnel axis strike, also have obvious influence on stability of tunnel rock. The study can offer significant reference for tunnel construction.
DEFORMATION AND MECHANICAL PROPERTIES OF THE LARGE UNDERGROUND CAVERN SURROUNDING ROCK WITH COMPLEX EXCAVATION
TANG Jun-feng, XU Guo-yuan, TANG Xue-mei, LI Xue-zheng
2009, 15(3): 233-244.
Abstract (149) HTML (57) PDF (576KB)(8)
Abstract:
Complex geological condition and construction procedure are often met while constructing the big underground cavern, so study of stress and deformation of the surrounding rock can not only help us further understand the mechanical properties of rock mass, but also provide reference for support design and construction of big underground cavern. Deformation and stability of the underground cavern mainly focus on the crown of the chamber. Taking the underground power house of the Xiangjiaba hydropower station as an example, and introducing the three-dimension discrete element method (3DEC), the authors has studied the variations of displacement and stress under the complex excavation condition, compared the calculated data with the monitoring results, and proposed that the proper support distance is 5m delay the constructing face.
COUPLED RELATIONSHIP BETWEEN CREATED AND NATURAL FRACTURES AND ITS IMPLICATION TO DEVELOPMENT
WAN Xiao-long, GAO Chun-ning, WANG Yong-kang, ZHANG Zhen-hong, YAN Hai-long, AN Ming-sheng
2009, 15(3): 245-252.
Abstract (239) HTML (124) PDF (318KB)(15)
Abstract:
According to outcrops, formation microscanner logging (FMI), paleomagnetism oriented cores and stress variation difference experiment, a close study has been made on the natural fractures of super-lower permeability reservoirs in the Yanchang Formation of the Ordos basin, and in combination with microseismic monitoring technique, an analysis carried out on the relationships between created fractures and earth stress and natural fractures. The results show a good coupling between created fractures and natural fractures. In northern Shaanxi, the well-developed natural fractures and heterogeneity of rocks lead the created fractures to stretch mainly along the natural fractures. In eastern Gansu, however, the natural fractures are poorly developed and the crushed fractures are controlled by present stress field. Therefore, in well pattern arrangement of super-low permeability reservoirs, our attention should be paid not only to the growth degree of the natural fractures but also to the orientation of natural fractures and their relation with the present stress field.
EXPERIMENTAL RESEARCH ON MECHANICAL PROPERTIES OF LIMESTONE AND SANDSTONE UNDER HIGH TEMPERATURE
QIN Ben-dong, HE Jun, CHEN Lun-jian
2009, 15(3): 253-261.
Abstract (191) HTML (98) PDF (478KB)(8)
Abstract:
The mechanical properties of limestone and sandstone under high temperature were investigated by the experiment device used to heat rock designed by ourselves and servo-control testing machine RMT-150C. The results show that the longitudinal wave velocity of two kinds of rocks gradually reduced with temperature increasing. The complete curve of stress and strain under uniaxial compression went through 4 stages, namely densification, elasticity, yielding and failure. They both displayed brittle fracture after reaching peak strength, with the sandstone rupturing and the limestone showing failure like a bundle of grass. The high temperature weakened their strength. Their peak stresses reduced with temperature increasing. At 700 ℃, the peak strength of limestone decreased by 84.59 %, while that of sandstone only decreased by 22 %. Their peak strain increased with temperature increasing, but differed in details. For limestone, its peak strain increased by 30.57 % at 500 ℃, but almost kept unchanged at the higher temperature, and even shaw a little decrease at 700 ℃.For sandstone, however, the peak strain increased by 80.63 % at 700 ℃, displaying a connection with the variation of microstructure. With temperature increasing, their elastic modulus and deformation modulus decreased. At 700 ℃, limestone decreased by 86.8 % in elastic modulus and by 83.9 % in deformation modulus, while sandstone decreased by 46.94 % in elastic modulus and by 53.06 % in deformation modulus.
APPLICATION OF LATTICE BEAM AND ANCHOR PIPE GROUTING COMPOSITE STRUCTURE TO FRACTURED ROCK SLOPE REINFORCEMENT
JIANG Xue-liang, CAO Ping, YANG Hui, MENG Zhuo-chao
2009, 15(3): 262-269.
Abstract (166) HTML (62) PDF (243KB)(3)
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The lattice beam and anchor pipe grouting composite structure is an effective engineering measure in landslide control. This paper deals with the mechanism of lattice beam and anchor pipe grouting, the principle and procedure of calculation by simplifying the lattice beam as Winkler elastic foundation, and the design of anchor pipe grouting for application to fractured rock slope reinforcement. As a case study, the lattice beam and anchor pipe grouting was used in control of K129 slope of Changzhang highway and brought about a satisfactory result. This method will prove to be useful to the same engineering.
ANALYSIS OF NUMERICAL SIMULATION METHOD FOR PALEO-TECTONIC STRESS FIELD
ZHOU Chun-mei, ZHANG Ze-jun, Li Xian-fu
2009, 15(3): 270-280.
Abstract (174) HTML (81) PDF (496KB)(12)
Abstract:
This paper analyses the numerical simulation method for Paleo-tectonic Stress Field from three aspects, namely tectonic simulation target, building of the tectonic model and tectonic modeling. Taking Chengzhuang coal mine, Jincheng City of Shanxi Province as an example, and based on field investigation on macro- and micro-tectonic features, the authors have established a plane-strain and three-dimension geological model, and obtained the mechanics parameters and fracture criterion of rock and boundary condition of the model. Using the large numerical simulation analysis software such as ANSYS and FLAC, they have determined the magnitude of palaeo-tectonic stress as the boundary condition of model and the loading sequence of palaeo-tectonic stress. The simulation results reveal two stages of large tectonic movement in the study area, the first movement in E-W and then another in N-S. Accordingly, a tectonic stress of 60 MPa was imposed in E-W deirection and 110 MPa in N-S direction. The acting pattern of the stress caused the simultaneous appearance of most shear joints on the earth surface and in the 3# coal rock. These rules not only offer important reference for understanding of deep condition of coal and the gestation condition of move fault in coal, but also have great significance for prediction of coal and gas outburst in stress concentration area of rock mass.
CHARACTERISTICS OF FRACTURES IN THE SANDSTONE RESERVOIRS OF YANCHANG FORMATION IN SOUTHEASTERN ORDOS BASIN
TIAN Ya-ming, SHI Ze-jin, SONG Jiang-hai, WU Xiao-ming, GAO Xiang, ZOU Yong-dong
2009, 15(3): 281-288.
Abstract (197) HTML (88) PDF (439KB)(14)
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The Yichuan-Xunyi area lies on southeast margin of the Ordos Basin. Bore core and slice observation and accounting, along with image logging data analysis, reveal main E-W orthogonal fractures in the studied area. The study of homogenization temperature of fluid inclusions in fractures, sedimentary history, and structural evolution in the studied area indicates that the fractures of the Yanchang Formation was mainly formed at terminal Jurassic- Early Cretaceous. R/S fracture analysis, a useful method for prediction of fracture distribution, has been utilized to identify fractures distribution areas.
CHARACTERISTICS OF THE PALEO-STRESS IN THE SOUTHWESTERN MARGIN OF XUEFENG UPLIFT AND ITS SIGNIFICANCE FOR PETROLEUM GEOLOGY
CUI Min, TANG Liang-jie, WANG Peng-hao, GUO Tong-lou, LU Xing-bin
2009, 15(3): 289-295.
Abstract (104) HTML (85) PDF (266KB)(21)
Abstract:
Based on the geological survey, balanced cross-section analysis and regional tectonic evolution, we take advantage of rock acoustic emission information to restore the maximum paleo-stress in the southwest margin of Xuefeng Uplift, and discuss the relationship between the maximum paleo-stress and hydrocarbon accumulation and damage. The results show that the study area has undergone five key structural reforms of different intensities. In the early Paleozoic and Indosinian cycle, the tectonic movement is weak, and the maximum paleo-stress are 13.3 MPa and 24 MPa respectively, equivalent to the main accumulation period of Majiang ancient reservoir. The high-frequency and high-intensity paleostress correspond to accumulation and damage of Majiang ancient reservoir. The Neopaleozoic structural deformation with the maximum paleo-stress of 92.6 MPa represents the formation of the reservoir. The Yanshan and Himalayan structural movements, with the restored paleo-stress from 23.3 MPa to 74.4 MPa, cover the period of extensive destruction of paleo-reservoir.
ANALYSIS OF THE SEALING PROCESS OF FAULTS IN MEMBER 1 OF SHAHEJIE FORMATION IN THE DONGYING SAG
XIAO Shu-ming, WANG Guo-zhuang, ZHONG Jian-hua, MENG Wei
2009, 15(3): 296-304.
Abstract (161) HTML (63) PDF (191KB)(2)
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The Dongying sag is located in southeastern part of the Jiyang Depression. The study area diaplays a great complexity of fault system in plane and a high diversity of structure in section. Based on a study of sealing process of faults in Member 1 of the Shahejie Formation, the authors have summarized the mechanism and affecting factors of sealing process of faults, and analyzed the method of quantitatively and qualitatively evaluating the sealing process of faults. Finally, a discussion has been made on the effect of compression and geochemistry on the sealing process of faults.
THE CHARACTERISTICS AND AFFECTING FACTORS OF GLUTENITE RESERVOIRS IN NORTHERN YONGXIN AREA OF DONGYING SAG
MENG Wei, ZHONG Jian-hua, WANG Jia-wei
2009, 15(3): 305-314.
Abstract (215) HTML (141) PDF (305KB)(10)
Abstract:
The Dongying sag is located in southeastern part of the Jiyang Depression. A study has been made on main rock types, type of reservoir space, physical characteristics and affecting factors of the glutenite reservoirs in northern Yongxin area in the Dongying sag based on core observation, thin section analysis, physical property analysis, scanning electron microscopy. The results show that the glutenites are of a low compositional maturity and textural maturity, and the reservoir spaces are intergranular corroded hollow, moldic pore and cementing corroded hollow. The dominant factors affecting physical characteristics of the reservoirs include burying depth, diagenism and sedimentary facies, of which the burying depth serves as a fundamental factor affecting physical properties of the reservoirs.
GEOLOGICAL CHARACTERISTICS OF GAS ON SOUTH LIMB OF GEQUAN COAL MINE
LIU Guo-lin, PAN Mao, XIE Hong, SU Jian-guo
2009, 15(3): 315-320.
Abstract (173) HTML (101) PDF (144KB)(1)
Abstract:
In the Gequan coal mine, such geological structures as folds and faults are extensively developed, and the geological structures are more complex on its south limb than on its north limb. A study of gas geology on the south limb indicates that the geological structures are leading factors bringing about the abnormity in gas effusing. Some suggestions and measures are given for forecasting the abnormal gas effusing.