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Chengdu, China

Wang M.,PLA Logistical Engineering University | Shi S.-Q.,PLA Logistical Engineering University | Yang Y.-K.,Geobrugg Chengdu Co.
Gongcheng Lixue/Engineering Mechanics | Year: 2014

Because field tests could not be used to obtain energy absorption in individual components and support system reactions due to restrictions on testing methods, a numerical simulation of a flexible rock-shed under impact of rockfall was carried out. The numerical simulation model for the flexible rock-shed was developed based on reasonable assumptions, theoretical analysis and experimental results. In order to validate the numerical model and numerical calculation method, the numerical simulation results were compared with the experimental data from during the impact of the rockfall, including the displacement of ring nets, the peak load on horizontal and hoop cables, the deformation of the rock-shed, and the strain-time curves of the steel vaulted structure. The results show that the numerical model and numerical calculation methods are shown to be reliable in predicting the dynamic behavior of this rock-shed under rockfall impact, and will be employed to investigate the performance of this structure.


Wang M.,PLA Logistical Engineering University | Shi S.-Q.,PLA Logistical Engineering University | Yang Y.-K.,Geobrugg Chengdu Co.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2012

Calculation method for equivalent radius of rings was deduced through static tests and theoretucal analysis of a single ROCCO ring. Calculation models with two different connection forms of a ring net were put forward. Four ROCCO rings were connected to a single ROCCO ring in the first connection form (Model 1) and six ROCCO rings were connected to a single ROCCO ring in the second connection form (Model 2). Static and dynamic energy dissipation capacity of the two models were studied with numerical analysis method. The results indicated that (1) the energy dissipation capacity of the single ROCCO ring in model 2 is greater than that in model 1 when ROCCO rings are the same in both models; (2) the deformation displacement in model 2 is shorter than that in model 1 under rockfall strike with the same kinetic energy when the two models are made of the same material; the rockfall impacting load in model 2 is lower than that in model 1 at first, and it grows greater than that in model 1 with radius of rockfall growing; (3) energy dissipation capacity limitation under rockfall impacting grows with radius of rockfall growing; the energy dissipation capacity limitation in model 1 is greater than that in model 2, and the dissipation capacity limitation in model 2 grows greater than that in model 1 when radius of rockfall grows to some level. So the second model could be adopted to reduce the costs when the deformation displacement of a protective system was taken into consideration and an economical and reasonable connection form could be chosen based on the characteristic of the rockfall when the energy dissipation capacity limitation of the system was taken into consideration.


Wang M.,PLA Logistical Engineering University | Shi S.,PLA Logistical Engineering University | Yang Y.,Geobrugg Chengdu Co.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2013

The main disadvantage of conventional concrete rock-shed is the need for a massive foundation due to the deadweight of the structure, and constructing such a structure is usually very difficult and expensive. To overcome the construction difficulty and reduce costs, a new type of flexible rock-shed composed of steel vaulted structure and flexible ring nets was proposed. Aiming at developing knowledge for the proposed flexible rock-shed, a 1:1 prototype model was designed and manufactured to withstand the impact energy of about 250 kJ in the impact experiment. It is shown that the structure can withstand the impact energy of about 250 kJ and may be reused after some maintenance on the steel vaulted structure. By employing dynamic strain rosettes, load cells and high-speed camera, the local strain variation, peak loads and impact time during the impact process were recorded. Based on the analysis of experimental phenomena and data, some improvement measures for the flexible rock-shed were suggested.


Wang M.,PLA Logistical Engineering University | Shi S.-Q.,PLA Logistical Engineering University | Cui L.-M.,PLA Logistical Engineering University | Yang Y.-K.,Geobrugg Chengdu Co.
Gongcheng Lixue/Engineering Mechanics | Year: 2016

U-brake energy dissipator is a new important component in the passive protection nets, which consists of a steel plate band, a cylindrical roller and a sleeve. The main function of the energy dissipator is to decrease the impact force on the anchors and cables, and to dissipate the impact energy of the rock-fall. Because there was no relevant engineering experience in the design theory and application of the U-brake energy dissipater, quasi-static tensile tests were carried out repeatedly. The results showed that: U-brake energy dissipators had better performance under the repeated tension; the starting force and the energy dissipation capacity were increased at the first tensile tests due to the plastic hardening effect of the material; the steel plate band exhibited brittle fracture similar to the fatigue failure at the fourth tensile test. Based on the related phenomena and the results of repeatedly tensile tests, the energy method was proposed for the theoretical analysis on the starting force and the energy dissipation performance. A theoretical calculation method proved by the experimental data was deduced and could be used as basis for the engineering design of U-shaped energy dissipators. © 2016, Engineering Mechanics Press. All right reserved.


Wang M.,PLA Logistical Engineering University | Shi S.-Q.,PLA Logistical Engineering University | Yang Y.-K.,Geobrugg Chengdu Co.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2011

A ring-brake energy dissipater of a passive system consists of tubular steel loops and aluminum compression sleeves, and steel cables drilled through the tubular steel loops are connected to a anchor rope and a support rope. The ring-brake energy dissipater used in the system is based on their great slip resistance capacity which can dissipate the kinetic energy and alleviates the impact load. Based on the effect of a ring-brake energy dissipater in a passive system, static tensile tests and FEM dynamic simulation were carried out. The numerical results with a ring-brake energy dissipater at the low speed load showed the correlation to the static tensile tests. The slip resistance increased and the energy dissipation performance was improved with the loading speed increasing. In addition, the influences of the length of the aluminum compression sleeves on the sliding force and the dissipated energy of a ring-brake energy dissipater were studied. The results showed that the energy dissipation capacity of the ring-brake energy dissipater increases singificantly in the beginning, but no significant increase occurs lately; the sliding force firstly decreases and then increases with increase in the sleeve length; when the aluminum compression sleeves are in appropriate length range, the ideal energy dissipation efficiency obtained with the dynamic simulation is close to that of the static tests.

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