Abstract
Aiming at the dynamic disturbance problem of the upper rock anchor beam concrete support structure caused by the blasting excavation of the lower rock mass of the underground powerhouse of the hydropower station, the dynamic finite element software was used to numerically simulate the cumulative damage characteristics of the rock anchor beam concrete structure under multiple blasting, which aims to study the effect of blasting times and blast center distance on the cumulative damage characteristics of rock anchor beam concrete structures in two directions at different ages. The results show that 7 days after the completion of the concrete pouring of rock anchor beam, the damage and destruction effects are produced under the single blasting action. 28 days after the completion of the concrete pouring, there is basically no damage and destruction under the action of five times of blasting. 14 days after the completion of the concrete pouring, the growth process of the cumulative damage effect of the rock anchor beam concrete structure under the disturbance of the blasting excavation of the underground powerhouse shows nonlinear increasing characteristics with the increase of blasting times and nonlinear decreasing characteristics with the increase of blasting center distance. The cumulative damage of rock anchor beam along and perpendicular to the axis of powerhouse conforms to the relationship of cubic polynomials with the blasting times, which also conform to the relationship of quartic polynomial and quadratic polynomial, respectively, with the blast center distance.
Highlights
In the layout of underground powerhouses of modern hydropower stations, especially pumped storage power stations, rock anchor crane beam structures are mostly used [1,2,3]
Ramulu et al [11] pointed out that repeated blasting loading during excavation will accelerate the development of damage area of surrounding rock. e research shows that the process of the cumulative damage leading to the
It is of great significance to carry out the experimental research on the cumulative damage degree of concrete structure blasting and the attenuation law of blasting vibration propagation
Summary
In the layout of underground powerhouses of modern hydropower stations, especially pumped storage power stations, rock anchor crane beam structures are mostly used [1,2,3] Because it undertakes the operation function of the crane in the powerhouse, it belongs to the core control object in structural design and construction. It is of great significance to carry out the experimental research on the cumulative damage degree of concrete structure blasting and the attenuation law of blasting vibration propagation. In the aspect of damage research of blasting load on concrete supporting structure, Duan et al [12] used wavelet packet analysis technology to calculate the energy value in different frequency band of vibration signal under different blasting conditions (blasting times and blasting center distance) and discussed the influence rule of different blasting conditions on energy signal distribution. Yao et al [17] believed that as the height difference increased, the particle vibration velocity of the high side wall gradually decreased and the maximum tensile stress appeared at the top or bottom of the rock anchor beam bonding surface, which has a good correlation with the horizontal particle vibration velocity. e maximum tensile stress and particle vibration velocity at the arch foot of the crown are relatively large, while the maximum tensile stress and particle vibration velocity above the arch foot decrease rapidly [18]
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