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Copyright of Earthquake (1000-3274) is the property of Editorial Office of Earthquake Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Earthquake (1000-3274) is the property of Editorial Office of Earthquake Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rockfall in limestone mines is a common geohazard in the Changdu area of eastern Tibet and one of the leading geo-safety issues that mining enterprises and railway projects are faced with. We carried out a detailed geohazard survey using the methods of general geology, structural geology, and geohazard geology. We found the rockfall development pattern, characterized rock mass structural planes, discussed the collapse's mechanism, and established its failure mode. The results show that rockfall sites in the study area show a linear spreading along the fold and thrust zone. Five groups of steep-dip structural planes have developed in the rock body, including the longitudinal joint (S1), the transverse joint (S2), the X-type conjugate shear joints (S3 and S4), and the interlayer shear joint (S5). Paired with regional folds and hedging faults, these structural planes cut the rock mass into broken blocks. The collapses are the product of coupled internal and external dynamic geological processes. The sedimentary foundation of the rockfalls in the Qamdo area is the limestone from the upper Triassic Bolila Formation (T3b) formed in the intracontinental rift basin. The strongly folded orogeny triggered by the Cenozoic (Cz) India-Eurasia collision laid down the tectonic framework in the region, which is the essential condition for rockfall development. The strong Neotectonic movement since the Quaternary (Q), frequent hot and humid climate alternations with abundant rainfall since the Late Pleistocene (Q3), everyday human activities, and other internal and external dynamic coupling effects are the main triggering factors of the rockfall disaster. Three failure modes of rockfall are identified, namely toppling, falling, and sliding. The research results have specific guiding significance for rockfall prevention and control in the karst area and the railway construction in the Sichuan-Tibet area. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Geodesy & Geodynamics (1671-5942) is the property of Editorial Board Journal of Geodesy & Geodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Geomechanics is the property of Journal of Geomechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: At present, the application of new materials and new energy in vanous fields continues to deepen, and rare metal deposits have ushered in a worldwide upsurge of research and exploration. The Keketuohai rare metal deposit is the earliest developed deposit for rare metal mineral in China. However, the thermal infrared ( TIR) characteristics of minerals and rocks from this deposit have not been studied, which restricts remote sensing geological survey and relevant studies. OBJECTIVES: To analyze the characteristics of thermal infrared spectra of minerals and rock assemblages from the Keketuohai deposit, and provide the basic data for rare metal exploration. METHODS: A portable thermal infrared spectrometer was used to measure the spectrum data of typical minerals and rock assemblages of Keketuohai No. 3 vein. Data was analyzed using techtonics/ structural geology ( TSG) and related databases. RESULTS: Typical rare metal minerals like spodumene, lepidolite, beryl and tourmaline can be separated with TIR. Compared with lepidolite, there was a new diagnosed peak for the TIR spectrum of lepidolite - bearing pegmatite. The spectrum peaks of spodumene - bearing pegmatite and tourmaline - bearing pegmatite were significantly shorter than those of spodumene and tourmaline. However, the spectrum peaks of beryl - bearing pegmatite were shorter than the peaks of beryl. CONCLUSIONS: A database of thermal infrared spectroscopy characteristics of typical minerals and rocks in the Keketuohai has been established, and the thermal infrared spectroscopy characteristics of spodumene and lepidolite, ore - bearing pegmatites and surrounding rocks in rare metal deposits have been summarized in this study. Basic data support for the identification of rare metal minerals using thermal infrared spectroscopy and the exploration of granite pegmatite deposits has also been provided. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Brittle structures are formed in the shallow crust and record the deformation process of shallow crust structures. How to precisely define the age of shallow crustal deformation is one of the hoispots and difficulties in structural geology research. Brittle structural deformation occurs in a lower temperature and pressure environment, which results in a faster rock strain rate and a relatively weaker metamorphism and metasomatism. As a result, it is difficult to form syntectonic new minerals similar to the measurable age of ductile deformation, which makes precise dating of brink- structures become a difficult problem in the field of earth science. In recent years, the calcite U-Pb dating technology has made important progress, and the calcite U-Pb dating from brittle structural deformation can accurately date the age of structural deformation. The research progress of the calcite LA-(MC-) ICP- MS U-Pb dating technique in recent years was summarized-the characteristics of the syntcctonic calcite vein, the theoretical basis of U-Pb isotope dating of calcite. the LA-(MC-) ICP-MS UP-b dating technique of calcite and its examples of application were systematically introduced. Furthermore« pointing out the key problems and technical difficulties of this method at present depends on the geological significance of calcite UPb age and the success rate of age determination. Identifying syntcctonic calcite veins in the field- dividing different stages of calcite and determining primary and secondary domains, can accurately reveal the geological significance of its age; besides, the accuracy of dating results can be improved by delineating the optimal target area to be measured-choosing reasonable common lead correction method and searching for ideal calcite reference materials. [ABSTRACT FROM AUTHOR]

The physical simulation experiment has been developed rapidly and applied widely. Based on analysis of development course of physical simulation experiments in recent years, taking the NW trending faults in Huangdao area as an example, a geological model was established by combining a large amount of geological data in this area in order to get a further study of physical simulation experiment in structural geology. The experimental result from semi-quantitatively to quantitatively indicated that the structural evolutions of the study area had mainly experienced several periods with strong activity: Late Jurassic Epoch, Late Cretaceous, Paleogene, and Quaternary. Meanwhile, the forming mechanism was mainly controlled by NW-SE extensional stress field, and the main activity of fault system was about Late Cretaceous, which provides strong evidences for the previous study of dynamic evolution, Some new understandings of dynamical evolution mechanisms in Huangdao area have been also suggested. [ABSTRACT FROM AUTHOR]

Goaf is one of threats in mines.A 3D laser-scan detection technology was used to detect and obtain the point cloud of its complex-shape effectively,and a goaf triangulation model was built. Goaf triangulation model and section can provide the basis for the design of adjacent stope and the safety analysis of the structures around it. Due to goaf complex shape,how to generate section outline and close model’s fracture surface was the key research on arbitrarydirectional section generation.A new generation algorithm of arbitrary-directional section for complex goaf triangulation model was studied and realized. It has functions including several interactive modes for selecting arbitrary section plane,intersection judgment and extracting intersection line based on simplified intersection criterions,generating section outline based on adjacent judgment of intersection line,and closing model’s fracture surface which combined with ears-cut,interpolation and triangulation between closed lines.Practical application shows that sections are generated efficiently,section outlines are generated precisely,and model’s fracture surfaces are closed well. [ABSTRACT FROM AUTHOR]

Five coals and three additives were used to investigate the influence of coal structural characteristics and additives on the performance of activated carbon prepared under the same conditions. The specific surface area, pore size distribution, iodine number were used to characterize the activated carbon.The results show that the changes in microcrystalline height and width of carbonized coals are mainly attributed to the different structural characteristics of the five raw coals.The microcrystalline structure of Taixi coal is most suitable in activation stage, and the activated carbon produced from Taixi anthracite with low ash and moderate volatile matter has the most porous micropore and the best adsorption capacity of CO2.Among the three additives, the effect of NH4Cl+KNO3 is the most significant, by which the specific surface area of the activated carbon is 1 093 m2/g, the micropore volume is 0.415 m L/g and the adsorption capacity of CO2 is 2.41 mmol/g（ 0.1 MPa, 25 ℃）. [ABSTRACT FROM AUTHOR]

In order to effectively extract the precursor information of containing macroscopic structural coal body in destabilizing failure, the authors have carried out the experimental research on the failure characteristics and charge signal law of intact coal samples and coal samples with a prefabricated large different-dip crack under uniaxial compression. The results show that with the decrease of pre-crack angle( the angle between the crack and the axial direction), the peak stress of coal samples decreases gradually, and the time reaching the peak stress de-creases, and the coal samples change from the tensile splitting failure to shear slip failure. At the same time, the new wing cracks are transformed from the wing cracks of the vertical pre-crack surface to the wing cracks of the parallel pre-crack surface. The pre-crack coal samples are more prone to rupture due to the existence of macroscopic cracks, and there are significant charge signals before the stress peak. Therefore, the precursory information of pre-crack coal samples is more easily captured than that of intact coal samples.With the pre-crack angle changing from 60° to 45° to 30°, the time of the first high-value charge signal in coal samples cracking process appears gradually advances,respectively 68.5% σc and 65.5%T,60.5% σc and 47.0%T,37.5% σc and 30.0% T( T for the whole destruction time of coal samples), and the amplitude of charge signal after the peak stress failure stage decreases gradually, as well as the mutation points in the charge accumulation curve increase and the first mutation point is advanced. The existence of pre-crack can affect the charge laws of coal samples by changing the deformation fracture process and the form of coal samples. Therefore, the charge signal related characteristics of pre-crack coal samples can be applied to detect the macroscopic geological structures and infer the occurrence of joints or faults of coal or rock mass reasonably. The study may provide new methods and approaches for the prediction of coal and rock dynamic disasters. [ABSTRACT FROM AUTHOR]

The mechanism of force chain formation and its evolution laws in the non-continuous structure system of top coal and overlying strata are the important foundation for the calculation of support loading, the optimization of coal mining technology and the control of mine pressure. By photoelastic experiment of particles under biaxially loading and bilaterally flowing conditions, the distribution of force chains in top coal and overlying strata of fully mechanized caving mining is captured and force chain network structure is studied by topology. The study shows that the distribution of force chain in overlying strata and top coal is uniform in the initial state. After mining, the arched chain is formed near the drawing opening, and extends towards the front and upper part of the working face as the working face advances. Three main configurations of force chains in overburden strata and top-coal are identified, namely, chain, loop and chain-loop coupling respectively, which are distributed in front of the working face, undisturbed overlying strata and mining disturbed overlying strata. Besides, these configurations can be described by Betti number. Through the analysis of the distribution characteristics of the force chains in mining field, the paper reveals the forming mechanism of the supporting pressure in front of the working face and the mechanical essence of the loading action of the working face. Based on the statistical analysis of force chain strength, force chain azimuth and contact force frequency, the force chains in top coal and overlying strata display statistical features as follows; strong chain distribution of undisturbed areas in the upper overburden is relatively uniform, whereas in the mining disturbed area strong force chains develop along the arch line;In front of the working face, the vertical force chain is the majority all the time. [ABSTRACT FROM AUTHOR]

With the method of physical simulation, theoretical analysis and field measurement, in the case of different overburden structures, this study investigates the law of overlying strata movement, relationship between support and surrounding rock under the load transfer of thick loose aquifer and integrated grouting reinforcement technology for wind oxidation zone. The results show that when there is only a key stratum in stope overlying strata,with the process of coal mining,in unconsolidated aquifer load transfer function, overlying strata large range collapse sink acting on the support below,and support force is bigger, and it is easy to occur support crushing accidents. When stope overlying strata has two key strata, its collapse to high key stratum form a ‘ voussoir beam ’ structure, the structure can make the transfer of aquifer overlying alluvium pressure shift away from stope support, and it improves the hydraulic support force status. Based on this,it takes 1512(3) working face of Gubei Mine as an example, according to the geological conditions of loose aquifer single key stratum, the method of J type horizontal wing branch hole is applied to reinforce the wind oxidation zone,aim to artificially build a high key stratum, this slows down the stress behavior when the working face is pressed,and the working face achieves the goal of safe mining, which verifies the rationality of the research results. [ABSTRACT FROM AUTHOR]

The problem of roadway support in deep coal mining or hard roof can be solved by special surrounding rock pressure release of stagger layout roadway. In this paper, the surrounding rock characteristic of gob-side roadways with or without coal pillar were analysed. Then the movement of main roof which has large impact on the stability of surrounding rock of gob-side roadway was discussed. The mechanical mechanism of pressure releasing and deformation yielding of surrounding rock structure system was studied by mechanical analysis and laboratory experiment. Results shows that the stagger layout enables roadway to be away from the stress concentration zone which transfers the pressure and avoids the problem of high ground stress. The gangue pillar structure cushions the dynamic load of falling roof and undertakes the weight of key block. The roof made up by gangue gives enough space for hard roof’ s movement which in another way protects the roadway. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Heilongjiang University of Science & Technology is the property of Journal of Heilongjiang University of Science & Technology Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To study the influence of isolated coal face mining on rock burst or strong tremor, the structure characteristics of thick-hard strata above 10305 isolated face were analyzed in this paper, and the seismic activity and burst risk were also monitored and analyzed. The results show that the strata structure above 10305 isolated face is an unsymmetrical isolated "T" structure, with the main key strata fractured on the short-arm side and non-fractured on the long-arm side, that is, the long-arm main key strata will fractrure and move in large-scale after face mining, and the risk of strong tremor or rock burst is relatively high. In addition, the inferior key strata can only form "O" fracturing structures, and the super-thick main key strata will form layered "O-X" structures, while the fracturing and movement of main and inferior key strata are the main sources of seismic activities. According to seismic monitoring, seismic events manily located on the long-arm side of "T" structure, especially the strong tremors occurred almost within the super-thick main key strata above 10305 and 10306. Moreover, the stong tremors present high ratios of S-wave to P-wave energy, which means they are mainly the results of shear fracturing or slip movement of main and inferior key strata. The burst risks caused by unsymmetrical "T" structure were evaluated by volocity gradient inversion, and the evaluation results are satisfactory. The big-diameter pressure-relief boreholes in coal seam and pre-blastings in main roof were implemented respectively in advance, and the burst effects of strong tremors were greatly reduced. [ABSTRACT FROM AUTHOR]

The characteristics of late tectonic activities were studied in this paper through the field geological investigation in Wuhu area. Combining with the analysis of the regional tectonic evolution, the authors propose that the later tectonic activities which had important influence on the Paleozoic strata are divided into compressive nappe structure at Indo-China period and extensional structure at Yanshan and Himalayan period. Furthermore, the study reveals the tectonic migration regularity and that the shale gas preservation of Paleozoic strata in Wuhu area was less affected by the thrust nappe tectonics of Indo-Chinese movement, while dominated by the extension tectonics of Yanshan and Himalayan movement. This cognition about the influence of late tectonic activities should be considered in the exploration of shale gas. [ABSTRACT FROM AUTHOR]

Aiming at fault diagnosis of diesel engine cylinder liner wear, the diesel cylinder block surface vibration monitoring in actual vehicle is conducted, and the diesel cylinder block surface vibration signals in different conditions are analyzed by using empirical mode decomposition (EMD). However, EMD sometimes cannot extract intrinsic mode functions(IMFs) accurately because of the mode mixing. Due to this problem, an improved local wave analysis method based on ensemble empirical mode decomposition(EEMD) is introduced, which is used to alleviate the problem of mode mixing, and the instantaneous frequency and the energy distribution of signals can be extracted by Hilbert boundary-spectrum. The measured results indicate that EEMD method is feasible and effective in fault diagnosis of diesel engine cylinder liner wear. [ABSTRACT FROM AUTHOR]

Bolt pretension has an important part in roadway support, but the study on strengthening characteristics of anchorage body with pre-stressed bolts still has many problems. Mechanics characteristics of detached anchorage body was researched by using RMT-150C testing machine, which was fabricated by wax-sand, pretension bolts and plainstrain restrain device. The results indicate that strength enhancement factor of peak strength, residual strength are positive correlation with rock strength and pretension of bolts. Strength enhancement factor is gradually increasing with pretension when rock strength is constant, and the residual strength enhancement factor of pretention of is greater than that of peak. There are corresponding relationship with stress-strain curve and bolts loads. Congruent relationship exists between stress-strain curve and bolt load. Before surrender point, bolt load increases slowly; however which increases rapidly after surrender point. Bolt load increases gradually on post-peak points, and constantly descends on flow phase. The higher strength of rock is, the lower increase rate of bolts loads are with the same pretension. The increase rate smaller is, the higher pretension is with the same rock. The loss of pretension in failure stage is much more of soft rock than that of hard rock. The strengthening effect in soft rock is obvious than that of in hard rock. Site practice shows that surrounding rock deformation can be decreased effectively with high bolt pretension. [ABSTRACT FROM AUTHOR]

On the basis of the existing support theories and actual support conditions, synergetic support was put forward by introducing the relevant synergetic principle to roadway support design. Synergetic support is to study the systemic synergy which includes supporting system, surrounding rock system, environment system and other subsystems, in order to make the roadway rapidly reach a balanceable and stable system from the non-equilibrium ultimately. Its purpose is to maximize the physical and mechanical performance of supporting members, effectively control the deformation of surrounding rock to achieve the synergetic supporting effect of 1 + 1>2. The synergetic supporting technique of rock bolts and anchor cables is mainly to study the prestressed synergy between them and the synergetic effect with other supporting parameters and supporting structures, in order to make rock bolts and anchor cables achieve maximum individual effect and bring about synergetic supporting effect. The results show that high strength rock bolts must be combined with high prestress and the prestress of rock bolts and anchor cables should match each other reasonably. Preloading above 40 kN on rock bolts and 140-160 kN to anchor cables will better the synergy. Preloading more than 60 kN on rock bolts to further enhance the active supporting character of rock bolts, at this time the preload of anchor cables must be 180-200 kN in order to better the synergy. [ABSTRACT FROM AUTHOR]

In this paper, a new method of fault diagnosis based on X and Y direction of the piston rod axis orbit is proposed firstly. The five graphs and six parameters were defined to reflect the operation state of the piston rod. Via this method, the traditional means limitation of only monitoring the single vertical displacement is solved. It has been verified the effectiveness of the piston rod axis orbit method by a set of simulation data and a fault instance. The method can analyze the direction and degree of the reciprocating compressor support ring wear, and provide an early warning of the piston components and piston rod running state. The established theory provides a theoretical basis for early warning and quantifying the fault diagnosis expert system rule by defining feature parameters. [ABSTRACT FROM AUTHOR]

The common character of thrust structure and gravity sliding is that there has a detachment plane with low strength and high shearing strain, which separates the upper wall and footwall which with different mechanical property and strain characteristic. The role of nappe structure for coal and gas outburst is thought 2 ways: 1 the compression during nappe structure formation makes the coal structure destroyed, some time is whole layer included, and other is at structural plane. So the soft coal is extensively developed ; 2 the compressive stress environment and strata thicken effect make a good condition for gas storage. Low-angle main slide fracture (most is reverse fault or overthrust fault) always forms a better gas closed system and it controls gas storage. Structural with compression character derived by nappe structure form gas closed system, too. So the mechanisms of action of nappe structure to coal and gas outburst is that creating the material foundation: large quantity gas and soft coal for coal and gas outburst. [ABSTRACT FROM AUTHOR]

Based on the theories of continuum mechanics and block dynamics, the present study primarily analyzed the tectonic stress field of the main shock faults in the Wenchuan Ms 8.0 earthquake happened on May 12, 2008. It discussed the interactions between block-block, block-fault, and fault-fault. The results showed that the strain energy migrates along with the fault propagation. The displacement filed, stress field and the distribution of total strain energy, and the mechanism of the process of the earthquake is explored quantitatively. The results also showed that the Wenchuan Ms 8.0 earthquake changed the tectonic stress field. There is energy concentrated area along the Wenchuan-Maoxian fault after the earthquake, so there should have energy release. [ABSTRACT FROM AUTHOR]