Reinforcing Method For Vertical Mine Shaft Collapse

Time:2022-12-16From:sinorock View:

Most of the safety accidents in the mining and excavation process will cause serious consequences, and the efficiency of subsequent rescue work is very important. As an important link in the mining process, shafts need to be repaired as soon as possible once they are damaged. This article describes how to support a mine shaft collapse.

Causes of Mine Shaft Collapse

1. Natural factors

Generally, most of the shafts that collapsed were due to the relatively broken and soft geology. As the excavation depth increased, the already soft rock would be crushed and then collapsed. The rocks that collapsed have low compressive strength and are mostly weak surrounding rocks. When the pressure of the concrete on the well wall exceeds the bearing capacity of the rocks, the rocks will be crushed and collapsed. There will also be groundwater in some areas, and the weak rock will be softened and deformed when it meets water. Then the friction between the well wall and the rock is reduced and finally result in collapse.

2. Human factors

Man-made reasons are mostly due to the use of inappropriate construction methods or technologies. Shaft construction needs to be designed according to the diameter, depth, geological and hydrological conditions of the wellbore. It can only be confirmed after a very rigorous demonstration to avoid irreparable consequences caused by safety accidents.

Shaft collapse support method

In 2005, there was a large-scale collapse of the wind shaft in the No. 2 mining area of Jinchuan, Gansu, and the shaft was completely blocked. After the collapse, technicians conducted repeated experiments and demonstrations on how to restore the shaft. Due to the complex conditions of the mine site, the rock mass is relatively broken and the stability is poor. Underground mining caused extensive movement of rock mass which ultimately caused the shaft to collapse. For this situation, anchor bars support can have a positive impact on the strength, structure and stress distribution of the surrounding rock.

1. Anchor Bars support

The self-drilling anchor bolts can complete the drilling, grouting and anchoring at one time, which can improve the mechanical properties of the rock and increase the yield strength. A certain stress can be applied to the surrounding rock through the self-drilling anchor bolt, and improve the stress state, tensile and shear resistance of the surrounding rock.

2. Hanging the Steel Mesh

The function of the hanging steel mesh is mainly to maintain the rock between the anchor bars under the condition of broken surrounding rock, prevent the broken rock from collapsing, and improve the stress of the rock formation on the surface of the well wall to provide a certain supporting force.

3. Shotcrete

The surface of the excavated surrounding rock is sealed by spraying concrete, which can fill the gaps and cracks in the rock mass, and promote the stability of the rock. The concrete will improve the cohesive force and shear strength of the rock, control the deformation of the surrounding rock, and prevent the occurrence of collapse. Concrete will form a dense and strong protective layer on the rock surface to prevent the surrounding rock from weathering.

The above are the common support methods for shaft collapse. The self-drilling bolt does not need a casing, has high construction efficiency and good anchoring effect, and plays a very important role in the emergencies such as slope reinforcement, foundation support. If you have any questions about the construction of self-drilling anchor bolts, welcome to consult.

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