Applied Mechanics and Materials Vols. 368-370

Abstract: This paper focuses on stability analysis of an artificial rock mass slope by a nonlinear finite element method (FEM). For a long time, rock slope stability problem is always an important research issue in the field of geotechnical engineering, which is related to human life and property safety as well as engineering security and efficiency. Therefore, the stability analysis and evaluation on rock slope is of great significance. The static and dynamic stability analysis on the artificial rock mass slope of WuAn power plant in China is carried on respectively in this paper by using the strength reduction method and FLAC3D software. In this analysis, static and dynamic instability criterions are enumerated, and the static and dynamic safety factors are calculated with the developed criterions of the displacement mutation, respectively. The analysis results show that the artificial rock mass slope is basically stable. It indicates that analyzing slope stability with strength reduction method is feasible.

Abstract: It presents a new structure of soil moisture probe which is designed for the solar automatic water-saving irrigation. DC two-probe method is used to measure resistivity of the new probe with different content of graphite under wet and dry conditions. The results show the resistance variation of the composite material with more than 25% graphite content is very small, its suitable for the production of two-pin probe; the conduction of composite material with less than 15% graphite content are greatly affected by the cement, its suited for the production of one-pin probe. The research results can be used as reference for choosing moisture probe according to different soil.

Abstract: This paper explores the design method of several typical mega plane frames, with the variables being the combination of varying amplification coefficient of moment at bottom sections of ground floor columns of the secondary frame on the main beams. The elastic-plastic dynamic analysis program Drain-2d+ of the plane structure is used to carry out the elastic-plastic time-history analysis for each typical mega-frame under the earthquake action. Based on the analysis, the deformation characteristics of the mega-frame, the emerging of the plastic hinge and the weak point of the overall structure under the earthquake action is developed, from which the correct method of obtaining the design value of amplification coefficient of moments at bottom sections of ground floor columns of the secondary frame on the main beams is concluded. The reasonable design values are recommended as the basis to provide some suggestions for the design of the reinforced concrete mega-frame structure.

Abstract: During running period of the Three Gorges reservoir ,failure mechanism of bank slope is one of the important scientific problems of geological disaster mitigation for reservoir bank. GongJiafang bank slope is located in left of Wu Gorge in Three Gorges of the Yangtze River, where damage events appeared in 175 m experimental water storage in 2008 and 175 m normal water storage in 2011.Study shows that, GongJiafang bank slope located in the core of the Heng Shi stream anticline developes two group of tectonic fractures .The first one is unloading fracture of bank slope, whose upper part is in transfixion or intermittent transfixion status,and the second one belongs to shear shear fracture. Bank slope presents cataclastic rock mass structure ,whose water physical properties are poor. The shear strength parameters of bank slope soil reduce after being immersed, a decreas of about 52 % on cohesion, and 30 % on friction. Regional new tectonic stress field control the macroscopic law for failure of GongJiafang bank slope .Especially max2 shear zone in new tectonic stress field is consistent with the first group fracture, which strengthen progress of the unloading fracture developement .Bank slope basically appear unstable failure along with the first group fracture. About 50% unbroken lower part of unloading fracture in GongJiafang bank slope locate in reservoir water level change belt between 145m and 175m.During the reservoir water level rising, stability coefficient of bank slope decreases from 1.31 to 0.88 after being immersed, and it is inevitable for bank slope to fail suddenly. Research results for further exploration on the formation mechanism of bank landslide in the Three Gorges reservoir and its mitigation has positive significance.

Abstract: This paper, setting the karst collapse in Siding lead-zinc mining area as an example, introduces the existing geological problem in this area, and then analyzes the cause of this karst collapse briefly. It states the main countermeasure of this karst collapse engineering from different angles and puts forward the idea that the method of clear block need to be adopted to solve the problem in the mining area, and achieves good results. We hope to provide some reference experience for other similar geological problems.

Abstract: The production forecast is a basic premise in the design of the oil exploration program. Accurate production predictions can provide guidance on the direction of oilfields exploration program adjustments and be able to determine the scale of mining of the oilfields. Because of the varying nature of geological reservoirs, oil field production forecast error is large. Because wavelet neural network is better features of convergence and dealing with complex geological conditions, so it can provide a more accurate prediction than the conventional prediction to heterogeneous reservoir. After the actual reference data are simulated, calculation error is very small, and to prove its production forecast can be used as the reference of the real reservoir exploitation.

Abstract: Simulation analyses of RC short columns are conducted under oblique horizontal seismic action monotonically using ABAQUS software. Concrete damaged plasticity model is used for concrete. Ideal elastic-plastic model is taken for steels. The results show that when the axial compression ratio was relatively low, the capacity of the columns increased with the increasing of load angle, because of the effect of tensile bars. For the relatively high axial compression ratio, the bearing capacity decreased with the increasing of angle, because of the effect of concrete in compression area.

Abstract: In order to solve the technical problem of gob-side entry retaining in inclined coal seam, combined with the practical mining conditions in a certain mine, this paper adopts the discrete element method, applies numerical simulation to analyze inclined coal seam gob-side entry retaining with three different supporting ways, and studies surrounding rock deformation characteristics of gob-side entry retaining. The research results show that the filling body upper boundary for right side can control the roadway surrounding rock deformation better compared with the boundary is used as the hypotenuse; Meanwhile, the pressure of surrounding rock of coal seam gob-side entry retaining is mainly from the impact of the immediate roof natural fall of the upper goaf tilt and the weight of caving coal gangue and coal seam of immediate roof above; According to the surrounding rock deformation characteristics of coal seam remain gateway along goaf, it is determined to use combined supporting method of concrete filling in roadway sides and anchor wire rope supporting inside the roadways, providing the design basis of gob-side entry retaining in coal seam for the similar geological conditions.

Abstract: In order to study the features of permafrost in Daxinganling, based on t he methods of field investigation and borehole drilling, as w ell as theoretic analysis and the effects of frozen soil geological conditions, topography features, frozen soil type and permafrost classification the freeze-thaw depth(m),main physical indicators of the Frost soil, natural water content, plastic limit Liquid limit index were analysis .the thaw settlement and frost heave were studied in this paper.

Abstract: According to sand-body genetic types, single sand-body is divided into five types include the polytectonic river-channel superimposed type, branching-river channel type, single river-channel type, sheet sand type and lentoid sand type. The use of multi-factor analysis to determine the index weight of control-degree of water flooding, recovery percent, water content, injection-production ratio and pressure distribution in different types of single sand-body, calculate different types of comprehensive Index of single sand-body adaptability. And analyze injection-production system to the well pattern adaptability in different types of single sand-body.