Static analysis of the body element at the top of hardfill dam cross section

Recently, Roller Compacted Concrete (RCC) has emerged as an applicable new construction material for gravity dams. Hardfill dam is one of the RCC dams which has some basic features as; a symmetrical cross section, a watertight upstream surface, no internal drainage in the dam body and use of lean RCC. The main advantages of this design are; low cost and fast installation, low stresses in the dam body; safer than conventional concrete gravity dams, especially in case of earthquake. There is some damages caused by static and seismic loads which can be observed in the upper part of the Hardfill dams In the design of such dams, hydraulic design engineers indicate some cracks in the upper part of the dam body element (block) which is observed in application. This element (block) which is located in the upper part of the dam body is built completely for cost savings. In this study, the linear elastic behavior of the upper part of the hardfill dam which is built on rigid (rock) foundations under static loads was investigated using dense finite element method. The dam height is fixed (100 m), the slope of the dam is 0.7H/1.0V, and the height of the block at the upper part of the dam body (a) is taken as 0, 3, 5 and 8 m. In order to see the effect of the hydrostatic load of the reservoir, the reservoir was completely filled and the reservoir water level was considered 3 m below the crest. Secondly in this cope of study, the value of "a" was fixed constant and analyses were done for different freeboard (hw) values. These analyses were done to determine the safety of the dam. The variation of the maximum and minimum principal stresses and the maximum displacements in the dam body and in the upper part of the dam body element (block) were examined separately for each case. Besides, for each "a" value, the safety factor of the dam against sliding and overturning and minimum and maximum stress at the heel of the dam was obtained. As a result of the analysis, more horizontal displacement leading to fractures in the upper part of the dam was observed for the value of a=5 m with the height of freeboard hw =1 m and a=8 m.