Applied Mechanics and Materials Vols. 405-408

Abstract: Rock instability and failure disasters are now common engineering-geological problems of underground engineering. The evaluation of stability of surrounding rock is a complicated uncertainty system problem, which needs various different research means. Rock coupling testing system composed of loose circle testing section, convergence monitoring section and multipoint displacement monitoring section is arranged at-600m level of Sanshandao gold mine; deformation law of roadway surrounding rock is well studied through long-term field testing and monitoring work. Achieved application results reveal overall stability of rock mass in gold mine deep area is relatively good, current impact caused by roadway excavation is not obvious. Coupling testing system is engineering practicable, which can meet the demand of rock stability evaluation study of underground engineering in Sanshandao gold mine.

Abstract: Using the mould pattern contrasting experiments the carrying capacities and deformation effects of underground tunnels within soft bed and top or floor strata are studied under high ground pressures in this paper. Through measuring mould strengths and deformation with different stratum and space position the relations of tunneling positions in different strata with carrying capacity and strains are obtained. It is shown that the soft seam tunneling under high ground pressure can bring about higher secondary stresses and have more acting effects than top or floor tunnels. In the same pressure conditions the carrying capacity of having top tunneling above soft tunnel decreases near 30% with that of having floor tunnel. The mutual effects with double horizontal spaces of tunnels decrease 25%. The experiment conclusions are important significance of conducting and applying for reasonable designing underground tunneling engineering.

Abstract: By 3D numerical analysis, the seepage force on the tunnel face was obtained and shows linearly increasing trend with the water level. By considering the average seepage force on the wedge boundary of 3D trapezoidal wedge model, the limit support pressure to keep stability of tunnel face under seepage condition was obtained. The total limit support pressure increases almost linearly with the water level. In order to consider the deformation seepage coupling effect, the 3D coupled deformation and seepage numerical analysis was further used to investigate the influence of the water level on the failure of tunnel face, the results show the failure mode changes with the increase of water level, and the limit support pressure increases nonlinearly with the water level.

Abstract: Zhejiang Province is Located in the Yangtze River Delta which the Soft Soil has Large Thickness and the High Underground Water Level.There is a Higher Requirement for the Optimization Design and Safety Construction of Deep Foundation.According to the Summary and Analysis of some Common Cause Failure of the Foundation Pit Engineering，we can Conclude that there are some Failure Mode in Soft Soil Area of Underground Diaphragm Wall Structure such as Foundation Pit System Instability，Basal Failure，Piping and the Flow of Sand Damage，Support Structure Instability and the Support of Low Strength or Buckling，and Summarizes some Prevention Measures on the Destruction of Underground Diaphragm Wall in the Light of these Failure Modes.

Abstract: Based on the measured hydrological data and the established mathematical model of Xiaomiaohong channel, the current and sediment distribution characteristics are researched and analysed. Some conclusions are drawn as follows: (1) The maximum velocity and mean velocity of the measuring points in the groove were generally greater than those at points in the open waters; spring tide and neap tide strength difference is apparent, spring tide should play a major role in the beach evolution. (2) Suspended sediment concentration in the open sea is significantly lower than that in the tidal channel; the bottom sediment concentration is generally greater than surface, bottom surface sediment concentration is 1.12 ~ 1.66 times (3) Median particle diameter of suspension sediment is 0.005 ~ 0.017, mainly for fine silt and very fine sand.

Abstract: Abstract. Based on the theory of numerical calculation, the SPH algorithm and FCBI algorithm were used to establish the corresponding water body model, and to calculate the fluctuations of the water by controlling water boundary parameters. In addition, the dam model was established based on the finite element method, and correspondingly two-way coupling with these two fluid boundary in order to examine the effect of fluid structure interaction by these two algorithms. The calculated results show that: the wave shape generated by this two algorithms is broadly consistent, however, the results obtained by the SPH algorithm can more completely show details; In addition, wave structure interaction effect calculated by SPH algorithm is stronger than the ones derived from FCBI algorithm, with the non-linear characteristic of the wave increase, the difference of the two algorithms is increasing. The the wave force calculated by the traditional linear wave theory needs some correction.

Abstract: Sediment settling velocity in the water is a sign of important physical quantities of sediment movement characteristics. Sediment concentration has a significant impact on the settling velocity. On the one hand,in the process of settlement,Single particle of sand would arose the movement of circumambient water. Because of the existence of other sand, circumambient water is blocked and loses the freedom of movement. Its equal to increase the water viscosity. And this makes the settling velocity lower. On the other hand, sand in the process of settlement brings along the circumambient water, and that goes with the sand down, and this makes the settling velocity bigger. Moreover, the existence of lots of sands will augment the turbid water density, and increase the buoyancy of every sand and finish its settling velocity. This paper states and trims the experiment data of the yellow soil at Station Hua yuankou and Fly-ash in Zhengzhou Power Plant, Using the Robertss experiential formula and Kynch experiential formula, the turbid water thickness and the time it needs are computed. After contrasting of the computed results, we have known that the laws which Fly-ash follows better than the silt.

Abstract: It is difficult to solve the near-bed sediment flux of suspended sediment transport equation under the non-equilibrium condition by theory analysis and numerical calculation. There are many variances, empirical coefficients and expressions undetermined. Bed shear stress is active methods to determine near-bed sediment flux. By comparing and analyzing of the research achievements, this paper provided the parameters spans, formulas of the variances and their correlations for determining the sediment flux, in the hope of promoting the sediment research.

Abstract: The navigable depth, affecting economic value, needs to be determined in ports and waterways with thickness of silt layer. Through the studies of silt samples, it is found that the relationship between viscosity and specific weight follows the cubic polynomial equations. A new method is proposed for determining the navigable Specific Weight, that is, the same increment of the viscosity and the specific weight () is regarded as the judgment condition for the navigable Specific Weight.

Abstract: Compared with each other of existed schemes and effects of the waterway regulating with complex shoals, from the viewpoint of water-sediment interacting evolutional properties and their effects on complex shoals of waterway, the results show that, the evolutional processes of channel morphology observe the principles of maximum entropy in equilibrium state and minimum entropy production rate in non-equilibrium state, in energy words, it is the minimum energy dissipation rate. The vortex moving dominates the sediment transport. From the practical engineering viewpoint, the general criteria for waterway regulating with complex shoals were investigated, the results may be valuable to regulating study of the mountain rivers.