Applied Mechanics and Materials Vols. 170-173

Abstract: Rock burst is a common mine dynamic phenomenon in the world, and the research on bursting liability of coal and rock is the foundation of rock burst’s prevention and treatment. This paper has a research on bursting liability of coal and rock of 11-2 coal seam which is the main coal seam of Zhuji coal mine, and through the research and analysis of coal seam burst energy index(bursting energy index, elastic strain energy index, duration of dynamic fracture) and rock seam burst energy index(bending energy index), this paper given that seam and rock in deep mining section of Zhuji coal mine has bursting liability, put forward a series of countermeasures such as the previous water injection, hole-drilling method, blasting distressing to the coal seam with the impact disaster for deep mining in Zhuji coal mine.

Abstract: Composite structure of mufti-ribbed composite walls-shear walls is composed of Multi-ribbed composite walls and shear walls which form a new kind of resisted load structure together. The paper analyzes the interaction of composite structure of mufti-ribbed composite walls-shear walls and pile-raft foundation with elastic-plastic mode of D-P. The load of superstructure is combined in the raft by substructure method, Finally，the paper obtain the distributed regularity of pile-raft foundation stress, strain by analyzing the influence of force performance which got by the large finite element software ANSYS analyzing interaction of superstructure and the pile-raft foundation-groundwork.

Abstract: Based on the investigation of the seepage causes wastewater reservoir of in one metal mine, the erosion mechanism is analyzed that the acid mine drainage erosion the earth-rock dam, and the technology program of vertical anti-seepage wall is chosen that use concrete with coal fly ash as anti-seepage wall. The practice has proven that such concrete vertical anti-seepage wall can improve the impermeability and structure of concrete, enhancing the anti-seepage wall durability under acidic environment. It can be reference to similar projects.

Abstract: The Joint Roughness Coefficients, JRC, is presented Barton and Choubey in 1977. A series of different rock joint profiles were reconstructed by means of the independent cut method (Voss, 1988) using the programs written by MATLAB language. The reconstructed joint profiles have different amplitude and roughness. JRC values of the joint profiles were calculated on the basis of an empirical formula founded by Tse & Cruden in 1979 using measure interval space 0.5mm on the profiles. The fractal dimension values of the joint profile were calculated by means of stick-measuring methods suggested by Xu in 1996. The relationships between JRC and fractal dimension for all joint profiles were analyzed and exist strong correlations. A new empirical equation describing the relationships was established based on nonlinear fitting analysis and can predict JRC values accurately.

Abstract: There are many methods of testing elastic wave velocities of engineering rockmass such as the elastic wave penetration test between adits, elastic wave test on the adit wall and the borehole sonic method etc, but the test results vary with different test methods. It is important to understand and apply appropriately the test results. Based on the field tests, the characteristics of elastic wave velocities under different test methods are studied. The research indicates that the main influence factors of different test methods on wave velocities include the rockmass occurrence environments and the test conditions. For the elastic wave penetration test between adits, the rockmass occurrence environments are basically unchanged, and the influences of the test conditions are little, so the wave velocity obtained by this method is more scientific. The study results are important for the reasonable evaluation of engineering rockmass.

Abstract: The stability of slope is closely related to stress-state. Assumptions about stress-state in the rigid body limit equilibrium method are not satisfied with the demands of deformation compatibility principle. So the stability analysis method compatible with slope stress and anchorage system should be established for anchored slope. The pseudo cohesion concept theory is used to analyze the improvement of stress-state due to anchoring measures, and the stability safety factor of anchored slope by sliding surfaces searching method is obtained, in which grid control is used and embedded in FLAC3D. The result shows that the safety factor with the pseudo cohesion theory is 1.43 while the strength reduction method is 1.41. The similar results for them show the validity of proposed method. What's more, the suggested method has an advantage of short time consuming.

Abstract: The mechanism of soil-compacting effect by silent piling is analyzed, and based on large-scale model box test, using soft clay of typical sites in Yancheng District, taking the single pile as the study objects respectively, and studying the soil compaction effects with the process of sinking into the single pile, analyzing the variation law of the soil deformation and pore water pressure while sinking into the single pile. The results shows that the greater the radial distance, the smaller of soil compaction effect, the influence scope of soil compaction effects on the displacement and pore water pressure reaches 0.6 times and 0.5 times the pile length sinking the single pile, which is accord to the actual engineering. The results could guide the pile foundation construction on soft soil.

Abstract: The research status of the rock acoustic emission technology had been discussed from three aspects, as the different status rock study, the processing technology study, the character analyzing technology study. The rock acoustic emission should be combined with the practical engineering, and to create effective rock acoustic emission processing and analyzing technology, to make the rock acoustic technology better adapted to the testing of the practical project.

Abstract: To rely on nuclear power plant water tunnel project, through the numerical simulation methods, we analysized the extent of rock deformation and stability of the process of excavation and supporting to reveal the deformation near the working face of rock tunnel.The research results show: When carrying out tunnel excavation, the plastic deformation zone in the horizontal direction perpendicular to the tunnel axis and the vertical downward direction are extended, the vault appears to sink, but also occurred in surface subsidence. Contrast the extent of tunnel excavation: The minimum extent is the tunnel axis perpendicular to the vertical downward, followed along the tunnel axis, the maximum extent is perpendicular to the direction of horizontal tunnel axis. Three kinds of excavation methods, a substantial volume reduction of sinking takes place in short steps and extra short steps excavation than the excavation of the top arch , and the surrounding area within the plastic is significantly reduced, which shows the smaller footage of the excavation the better control of the sinking of the crown.

Abstract: By discussing the current research status of the concrete acoustic emission technology from four aspects as: the concrete acoustic emission of different conditions; the characteristics of the concrete acoustic emission; the Kaiser effect and Felicity effect of the concrete acoustic emission and the analysis of the concrete acoustic emission data. The concrete acoustic emission research should be done with the practical project, and establish effective processing and analyzing technology of the concrete acoustic emission, to apply the concrete acoustic emission technology better to the measurement of real project.