Zhu Zhanyuan

The influence of materials on the breaching process of natural dams

In this study, a series of natural dam overtopping laboratory tests are reported. In these tests, the effect of seven different sediment mixtures on the breaching process was investigated. According to the test results, three stages of the breaching process of natural dams made of different materials were observed. Backward erosion was the primary cause for the incising slopes. The effects of backward erosion became stronger with the larger fines contents of the materials. With an increase in the median diameter (d50) of particles, the breaching time became longer. However, the peak discharge became smaller. With an increase in the fines contents (p), the median diameter of the particles and the void ratio were changed, which resulted in a decrease in the breaching time and an increase in the peak discharge. The breaching time and peak discharge were more sensitive to the median diameter than to the fines contents. The relation between breach width and depth was found to follow a logistic function W=ζ1+e−kD−D0

Vertical Dynamical Analysis Model of Heavy Vehicle-pavement-subgrade During Spring-thawing Period

Wkern0.5em =kern0.5em frac{zeta }{1kern0.5em +kern0.5em {e}^{left(-kleft(Dkern0.5em -kern0.5em {D}_0right)right)}}

Assembled constructional column building block of being under construction simultaneously with frame construction infilled wall

. The parameters ζ, k, and D0 are defined by a linear relationship with the median diameter and fines content. A breach of the side slope occurred as a tensile failure when the fines contents of the materials were large; otherwise, shear failure occurred. Furthermore, when the materials had fewer fines contents, the volume of the collapsed breach side slope became larger.

Assembled constructional column of being under construction simultaneously with frame construction infilled wall

This analysis is based on a highway project in Guangdong province, involving a tall, steep, and rock-excavating slope with cataclastic structures. Quantitative analysis of the stress-strain trend, possible failure models and safety factors during the slope excavation were investigated by the discrete element program UDEC. The following results were obtained: (1) The slope with joint fissure developed was in anticlinal core and the stability was greatly influenced by the extroversion of rock level. (2) The primitive balance of the slope was broken during the excavation, which induced large range shear failure zone in the internal part of the slope, and the whole circle-broken similar to soil slope appeared. (3) The excavation slope was in a critically stable state, but wide area landslide could be induced by certain triggering factors. Based on these results, a comprehensive treatment scheme was adopted and implemented through the methods, such as reinforcing the broken rock with concrete lattice beam-anchor (cable); minimizing erosion and preserving the slope strength with an efficient drainage system; and protecting the slope with grouted rubble. The integrity of the high standard highway was maintained and the slope was reinforced during time the plan was carried out.