Applied Mechanics and Materials Vols. 580-583

Abstract: The slope monitoring is an important part of the slope engineering. Through the reasonable monitoring, the engineers can get all kinds of information and the state of slope stability; provide scientific basis for the forecast about instability. Facing various methods and diverse information, the engineers can not consult books and make project efficiently. Based on the objective of safe construction, a database system including a comprehensive range of information about monitoring design, construction technology and equipment is built by achieving the design ideas of rapid and concise. By utilizing the development tools of Visual Basic and database platform of Access, the monitoring guidance system is developed with the consultation, editing, and analysis functions. The system provides a complete slope monitoring information platform to guide the engineering staff to quickly and accurately develop the design of slope monitoring.

Abstract: Based on MATLAB, the article apply BP artificial neural network theory on the forecasting problem of time sequence in geotechnical engineering, and find it is an effecting way to solve the forecasting problem of time sequence in geotechnical engineering.

Abstract: Slope stability analysis requires detect and control the stress and strain timely. Familiar with the slope‘s stress and strain changes in excavation process has important guiding significance for the actual construction. In this paper, choose a slope in Guangxi freeway renovation and expansion process as the research object. Use FLAC3D to analysis the stress and displacement simulation results of this slope excavation step by step. Summarize the excavation regular pattern.

Abstract: Flammable gases’s fire need more attention in spontaneous combustion study of coalmine. Their premixed combustion is modeled to deduce the corresponding temperature-time function. Basing on this function curve and Simon Ingberg’s early reports, their fire severity classification theory is established, including definition and equation of their fire severity, and definition of fire severity coefficient along with calculation of those coefficients of ordinary flammable gases. Applying this theory to a certain coalmine, calculate and audit fire severity of its 6 designed fire scenarios, in servitude to guidelines for fire protection technology there, and references for fire severity comparison among similar coalmines.

Abstract: The cubic law (CL) is one of the most commonly applied physical laws for flow through rock fractures and fractured media, but many studies indicate that the CL is often not adequate. We investigate the establishment conditions of valid applying the “cubic law” to flow in fractures. A dimensional analysis of the N-S equations yields three conditions for the applicability of cubic law, as a leading order approximation in a local fracture segment with parallel walls. These conditions may not be met in many natural rock fractures as whole and demonstrate that the “cubic law” should be exactly applied in local segments (local cubic law, LCL). In this way, a new 2D discrete equivalent model for natural rough fractures is introduced, and its equivalent aperture and flow formulation are derived. By comparing the developed model and experimental results of different fractures, good accuracy was found, and the model was validated. The model could be useful for theory studies of flows through real rock fractures.

Abstract: The hydro-electrical power station is planned to be built on the Jinsha River. The regional geologic structure is complex. On the basis of the geological engineering conditions and rock mass quality classification, the change of wave velocity of rock mass is used to analyze systematically the control function of corrosion of calcareous sandstone over rock mass quality. The modificatory standard of rock mass quality classification and the system of rock mass quality classification in the hydroelectric station have been carried out. The main results can be taken as the basic data and the theoretical proofs to evaluate the engineering rock mass stability.

Abstract: Anninghe rift is located on the western edge of Yangtze Block next to Tibetan Plateau, along the axis of a continental paleorift zone, Panxi paleorift. Recent studies have found that an upward mantle convection system existed since the late Pliocene in the deep lithosphere of a long and narrow area controlled by Anninghe fault. Lithospheric temperature distribution in the area has characteristics similar to that in Baikal and other modern rifts. A mantle upwelling area was in a constant state of “pull-subsidence.” Brittle rock mass of the shallow crust cracked into the new secondary subsidence blocks. A thick lacustrine sedimentary sequence of continental subsidence type developed. These all indicate that Anninghe rift is in an obvious tectonic activation state. It is believed that the tectonic activation of Anninghe rift has been produced by both horizontal squeeze from a plastic flow of the upper crust and expansion from mantle uplift. The pressure from the plastic flow of the upper crust is slightly greater than the expansion stress from the uplifting of lithosphere. Under this specific geodynamic environment, whether the tectonic activation of Anninghe rift can continue depends on the thermal motion rate of deep mantle materials and the eastward migration of the crustal materials of Tibetan Plateau.

Abstract: Fractured rock is a combination of rocks and fractures,the fractures which are ubiquitously distributed in fractured rock mass often constitute the flow and migration path of underground fluid and radionuclide.Discrete Fracture Network Model (DFN) was built with in-situ observations to evaluate the hydraulic conductivity tensor of rock masses.The fractures relation pattern with corresponding algorithm is given on the basis of computational geometric,and then the graph theory is employed as the mathematical model to represent the mutual positional relation of fractures.And then,with the use of Dijkstra algorithm, the hydraulic conductivity tensor could be obtained.

Abstract: Based on the collected geological exploration and underground mining data, this thesis has analyzed the development feature of faults of No.5 coal seam in Chenghe-Second coal mine and obtained fractal law of fault structure by fractal statistics. The result shows that the faults have a good self-similarity on the plane distribution and obvious fractal characteristics and that the larger the fractal dimension, the higher the complex degree of fault structures.