مهندسی عمران شریف (Aug 2019)
ANALYSIS OF CONDITION PHYSICAL HOMOGENOUS EARTH DAM IN OVER TAPPING
Abstract
Dams failure by the over tapping from them is common that have property and environmental damage. So, this research scheduled for showing dam failure. For collecting soil mechanic parameters and them effects on time failure Used from experimental models such as downstream. Therefor in Laboratory were made earth dam models with similar downstream and upstream slopes that slops were 1:1 and 1:2 slop in down and upstream dam. For embanked models used three types of soil which one model constructed S soil and two models from SC soil). Six earths dam's models were made in glass flume. Soils used had 1.05, 0.51 and 0.07millimeter diameter average and respectively angle internal friction were 14, 18 and 23. Experiments were done with putting up head water in pound with maximum level. Score profiles were depicted while water passes was started in step of time. Accordingly, height and width of score gap determined with point gage and laser meter in time steps. In first model with coarse-grain soil showed that gap width of score was stable in passing time but height of gap is formed to waterfall which this height was changed accelerate. In this case score model was depth. Additional, in second model that prepared with 25 percent core soil (adhesive soil) and 75 percent fine soil (non-adhesive soil). During the time width gap was increased because energy lost from hydraulic jumps below slop couldn't overcame top of dam's models so score profile showed that water fall with high was formed floor of slop. This waterfall until dam failure was stable. Finally. By considering Mechanic Soil Parameter in Coulomb tension behaviors of dams was analyzed. Also, in third model that prepared with 50 percent core soil (adhesive soil) and 50 percent fine soil (non-adhesive soil) diagrams of score was depicted. In this model during the time score gap width was increased but in gap height was formed with several waterfalls. Height of waterfalls were less height from second model. This case was effect on dam failure. Generally, with increases average diameter and angle internal friction effect on decrease time failure and made increase. In addition, mount of score in models was calculated and was investigated.
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