Study Of RCC Dams Strengthened With Steel Fiber Reinforced Concrete In Monolith For Seismic Resistance

As a result of the strategetic development of the western regions and the project for delivering electricity from the west to the east, China is developing hydropower resources and constructing hydropower projects very quickly in the 21st century. 70 percent of these hydropower resources distribute in southwestern of China which is also the high-intensity earthquake area. There are many dams with a reservoir storage capacity of more than 1×108m~3.The statistics show that about 40 percent of these dam sites' seismic intensity are more than intensity VII and 13 percent are more than intensity VI. Seismic safety is a key problem in the design of dams. Effective structural measures are very useful in improving the safety of dam and intensifying the resistance of load.With the advancement of Jin'anqiao hydraulic engineering, this paper carries on dynamic model test study and finite element analysis on steel fiber reinforced concrete (SFRC)-strengthened seismic mitigation measures for the dam. The main contents are organized as followed.1. Experimental study were made to study the characteristics of SFRC so as to find the method to simulate the SFRC in the model test. Consideration was given to tensile strength,compression strength and dynamic characteristics. It was experimentally established that tensile strength of SFRC is a little bigger than that of plain concrete and the steel fiber inside SFRC could prevent and suppress the crack and avoid brittle fracture.2. Sectional experiments of the dynami c model were made to Jinanqiao RCC dam and the results of the experiments were analyzed and compared. The analogy method of the SFRC laid down in the high stress region of the monolith and its influence on earthquake safety of the dam were studied. Classic sections were included in the model tests and non-seismic measure and SFRC measure of each monolith were considered respectively. The variable rules of amplification acceleration,starting crack acceleration and stress were analyzed respectively. The comparison of experimental results showed the measure could remarkably reduce the starting crack acceleration, significantly control the extension of crack and effectively improve the aseismic performance of the dam.3. Finite element analysis on steel fiber-strengthened seismic mitigation measures for the water holding monolith of Jin'anqiao RCC dam are carried out in the paper by using ABAQUS. In the paper, damage failure in the water-retaining monolith of Jin'anqiao RCC dam subjected to strong ground motion is simulated by a plastic-damage model based on damage index variables of tensile stress. The effects of SFRC to strengthen the dam are studied by using three different dimensions of SFRC zones and three volume ratios of SFRC. According to the above combination of SFRC's applied zones and volume ratios, the variable rules of equivalent crack width, crack propagation depth, displacement response and starting crack acceleration are analyzed respectively. The comparison of calculation results shows the measure can remarkably reduce the damage zone, significantly control the extension of damage zone and effectively improve the aseismic performance of the dam.