Three dimensional analysis of slope stability

Many high-rise buildings, bridges, and transmission towers are constructed on steep slopes in Hong Kong and are supported by large-diameter piles. These structures may be subjected to large lateral loads, such as those caused by typhoons, earthquakes, and high-speed vehicles. The margin of safety of the slope may decrease as a result of stresses transferred from the piles to the slope. To minimize the transfer of lateral load from the buildings to the shallow depths of the slope, an annulus of compressible material (sleeving) is sometimes formed between the piles and the adjacent soils. In this paper, a three-dimensional analysis is carried out to investigate the effects of unsleeved and sleeved single piles and pile groups on the stability of a cut slope. Mechanisms of load transfer from the piles to the slope are studied. The stability of the slope is evaluated using the strength reduction technique. The evolution of slope failure is examined and the factors of safety for both initiation of instability and global failure of the slope are identified from the numerical analyses. The sleeving technique is found to be capable of significantly reducing the stresses in the shallow depths of the slope in front of the piles, thus improving the local stability of the slope, but offers limited benefit with respect to global stability.Key words: laterally loaded pile and pile group, sleeving, slope stability, three-dimensional analysis, load transfer mechanism, factor of safety.

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In situ investigation of the primary recrystallization of alpha titanium in HVEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100110313 ◽

1978 ◽

Vol 36 (1) ◽

pp. 634-635

Author(s):

S. Naka ◽

R. Penelle ◽

R. Valle

Keyword(s):

Dimensional Analysis ◽

Texture Evolution ◽

Cold Work ◽

Three Dimensional ◽

Primary Recrystallization ◽

Thin Foils ◽

In Situ Investigation ◽

Grain Growth Model ◽

Alpha Titanium

The in situ experimentation technique in HVEM seems to be particularly suitable to clarify the processes involved in recrystallization. The material under investigation was unidirectionally cold-rolled titanium of commercial purity. The problem was approached in two different ways. The three-dimensional analysis of textures was used to describe the texture evolution during the primary recrystallization. Observations of bulk-annealed specimens or thin foils annealed in the microscope were also made in order to provide information concerning the mechanisms involved in the formation of new grains. In contrast to the already published work on titanium, this investigation takes into consideration different values of the cold-work ratio, the temperature and the annealing time.Two different models are commonly used to explain the recrystallization textures i.e. the selective grain growth model (Beck) or the oriented nucleation model (Burgers). The three-dimensional analysis of both the rolling and recrystallization textures was performed to identify the mechanismsl involved in the recrystallization of titanium.

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