Study of Passive Protective Net Protecting the Rockfall Caused by Open-Pit Blasting on High and Steep Slope

In order to prevent rockfall caused by open-pit blasting on the high and steep slope and ensure that the passive protective net structure has sufficient impact resistance, the mechanism of blasting flyrock causing rockfall is analyzed by using ANSYS/AUTODYN to establish the model of rockfall and passive protective net; at the same time, the influences of protective net size, rockfall kinetic energy, and rockfall size to the protective effect were also studied. The results show that under the condition of the same rockfall kinetic energy and rockfall size, the larger the size of the protective net, the longer the buffer time, and the impact force that net can sustain is greater; by assuming the protective net size and rockfall size to be a constant, the greater the rockfall kinetic energy, the less the interaction time between rock and net, and the greater the impulse force that net can suffer; similarly, by keeping the protective net size and the kinetic energy of rockfall to be a constant, it is found that the larger the size of the rockfall, the larger the interaction area and longer interaction time with the net, and the less net will be disrupted; the protective net used in the mine can intercept the rockfall caused by flyrock in blasting process effectively and ensure the safety of villager at the foot of the mountain.

Effects of Landslides on the Displacement of a Bridge Pile Group Located on a High and Steep Slope

Engineering practice shows that the deformation of the slide-resistant pile may be transferred to the adjacent bridge foundation on an inclined slope, which can compromise the safety of the entire bridge. However, this phenomenon has rarely been considered in the past. To reveal the deformation transfer mechanism between the slide-resistant pile and the adjacent structures, a full-scale field test was performed on a high and steep slope located in a section of a certain railway. A numerical analysis model was constructed to simulate the field test and validate its parameters. Moreover, parametric analysis was also conducted to examine the influence of the pile length, pile diameter, and arrangement of the pile foundation. The results show that the bridge pile foundation is simultaneously affected by the “load transfer effect” caused by the slide-resistant pile and “traction effect” of the sliding slope. With the distance between the pile foundation and the slide-resistant pile increasing, the dominant factor affecting the deformation mode of the pile body is switched from the “load transfer effect” to the “traction effect.” Furthermore, a critical embedment depth exists for the bridge pile foundation built on a high and steep slope, which varies at different locations along the inclined stratum. In addition, using a pile arrangement with a larger pile diameter and lower number of piles is more beneficial for controlling the horizontal displacement of the bridge foundation. The results of the research provide a reference for the safety control of the engineering on the high and steep slope.

Study on Construction Technology of Tunnel Entrance on High Steep Slope of Sichuan-Tibet Railway

The geological environment along the Sichuan-Tibet railway has the characteristics of plate splitting, frequent geological disasters, complex topography, large topography, cold climate, high cold and anoxia, etc. It is recognized by the world as one of the most difficult projects so far. Based on the construction of the tunnel entrance on the high and steep slope of the Sichuan-Tibet Railway, this paper conducts research on the construction of the tunnel construction, the reinforcement of the tunnel entrance and the protection of high and steep slopes. The integrated” tunnel entrance reinforcement system and the “carbon fiber lightweight active protection net” technology for slope protection are expected to provide a reference for the construction of the tunnel entrance of the Sichuan-Tibet railway high and steep slope.