Applied Mechanics and Materials Vols. 90-93

Abstract: Slopes of open-pit mine and ash storage are likely to occur the geological disasters of landslides, collapse, ground deforms and so on, due to geological structure, mining activity, etc. Lai Zhou Power plant is going to use the open-pit of Cang Shang gold mine as the ash storage field. Therefore, the long-term stability of the slope is of great significance. Through the geological investigation and analysis of open-pit mine slope, the conditions of geological and tectonic are summarized. On the basis of field monitoring, the stability of the slope is analyzed in detail. The estimated results can better correspond to the actual stability of the open-pit slope. Feasible practical control scheme and monitoring program are put forward according to the engineering practice

Abstract: Large amounts of sludge are produced in China each year. Its safe disposal and the recycling technology is the only way to solve the problem of sludge pollution, in which the sludge solidification technology is very important. Since the hygroscopic property and self-hardening property of paper sludge ash are important factors for developing cheap and effective sludge curing agent formulations, the research is practically valuable. The present research studies the basic engineering properties of paper sludge ash, its PH value, heavy metals in the extracting solution, hygroscopic property, microstructure and shear strength. The results show: the PS ash was weakly alkaline; the extracting heavy metals are of little pollution; hygroscopic property decreases with increasing pressure and there is a minimum water absorption; shear strength decreases as the water content increases.

Abstract: By analyzing a large number of in-situ stress data measured in underground deep coal mines, two types of in-situ stress fields exit in deep coal mines, σHvh and σvHh, which influences on the stability of underground deep roadways are analyzed by means of numerical simulation. The results show that the destruction of surrounding rock varies greatly in equal value stress fields with different types. In σHvh, the plastic zone of roof and floor of roadways is larger than the two sides, and stress concentration appears in front of heading face and in roof and floor of roadways, but not in two sides, more considerations should be given to the roof and floor supporting. In σvHh, plastic zone of two sides is larger than the roof and floor, and stress concentration appears in front of heading face and the sides of roadways, but not in the roof and floor, so more supporting considerations should be given to the two sides while protecting the roof.

Abstract: The model of the axis-radiate infinite element is developed for simulation of the infinite layered foundation underlain by a rigid base. Within the infinite element, the coordinate and displacement of any point are expressed by those of the nodes located on the artificial boundary, and concise mapping functions can easily express the attenuation character of the displacement field. By coupling finite and infinite elements, the elastic recovery capacity and radiation damping of the infinite layered foundation are simulated. In the numerical calculation, the infinite element mesh is performed only on the artificial boundary. Compared to FEM, the present approach needs less nodes and elements, and shows good accuracy and efficiency.

Abstract: In Wenchuan earthquake, liquefaction and relevant damage in Mianyang region were significant and of the three major regions, but the liquefaction phenomena were clearly different from Chengdu and Deyang regions. Through field investigation and engineering geological data analysis, this paper studies the liquefaction features and distribution in Mianyang area. Analysis shows that: (1) Liquefaction zones (belts) mainly were located in Youxian area of Mianyang city, Jiangyou city and Weicheng-Dongxuan town area; (2) Liquefaction has been observed in regions of intensities VII and VIII, but mainly concentrated in intensity VII; (3) Heights of water-jet were about one meter with the highest 3-4m; (4) The ejected materials in liquefied sites basically covered kinds of soil types, i.e., nearly 80% of fine sand followed by 11% of gravel; (5) Liquefied zones were associated with cracks, resulting in farmland, houses, a railway station, schools and factories damage in different extents. Jiangyou railway station is the most typical example of gravelly soil liquefaction. (6) The liquefied soil in Mianyang region is mixed, e.g., liquefied layers were gravel layers in Jiangyou city; sandy layer liquefied in Youxian area of Miangyang city; and the liquefied soil was probable gravel or sand in Weicheng-Dongxuan town area but the gravel liquefaction possibility was high

Abstract: The settlement characteristics of storage tank foundation at water-filling preloading stage and stable loading stage was analyzed based on numerical simulation. And the influences of foundation soil parameters on the settlement of storage tank foundation were studied. The research results show that Uplift appears at the place 1.3D away from the center of oil tank bottom, and the final uplift value is 10mm.The main factor which influences the consolidation speed of storage tank foundation is permeability coefficient. The consolidation settlement is determined by compression modulus and load.

Abstract: Stability analysis of excavated high slope is a complex problem. This work aims to a real excavated high slope in argillaceous mudstone, the strength properties of mudstone and instability mechanisms of slope had been studied separately by laboratory tests and numerical stimulate. The test results of residual-strength under large strain and softening-strength under rainfall infiltration were presented. The stability estimate basis of Bishop circular arc method and non-linear stress-strain analysis based on Duncan constitutive model had been carried out on the slope, using different strength indexes and Duncan model parameters obtained by triaxial drainage shear test. The results show that the landslides mechanisms caused by excavation and rainfall infiltration are relaxation failure and soften failure, separately. The deformation zone lies within the 0-4m soil layer and slope toe. The reinforcement measures of resistance piles set at slope toe and combined bolting and shotcrete set at slope surface were presented. After reinforced, the stability of excavated slope increased.

Abstract: The fragmentation of ore pass under loading belongs to one of the typical disaster in underground mine. This paper is concerned with the description and explanation of this phenomenon and presents brittle fragmentation for impact damage of rock block based on impact test, high-speed camera was used to study the relation between fragmentation and damage and the effect of the kinetic energy of projectile on them, the experimental results demonstrate that the damaged zone, invasion depth increase with the increase of the kinetic energy of projectile, but are influenced by the impact angle; the results show that prior to the impact kinetic energy reaches the critical value, the energy dissipation is mainly for damaged zone, when the impact kinetic energy increases to the critical value.

Abstract: The composite foundation fully takes the carrying capacity of pile and soil into account, which decreases the settlement of oil storage tank foundation and differential settlement of oil storage tank bottom apparently. Analyzing the changes of stress and settlement under different conditions and optimizing the parameters of pile have important significance in engineering practice. In this paper, with an actual project of oil storage tank for background, basing on the Drucker-Prager yield criterion, the FEM model of composite foundation has been carried out by using ANSYS procedure. And with simulating the status of composite foundation under the working load, the project properties of composite foundation are investigated. Further more, analysis on the impacts of different pile parameters on stress and settlement of composite foundation have been carried out. In the end, the optimization scheme of composite foundation design has been proposed.

Abstract: The horizontal vibration characteristic of the pile foundation is a key technology in dynamic design of foundation engineering. By researching on the horizontal harmonic loads in layered foundation, use horizontal vibration answers of buried foundation to deal with horizontal vibration impedance problems of pile tip. The transition matrix can be used to analyze the dynamic impedance function for horizontal vibration of pile foundation in layered foundation. And results in the paper is checked with traditional methods, which shows the both results fitting well.