1. Surrounding rock pressure
In order to prevent deformation and damage of surrounding rock, it is necessary to support the surrounding rock. The deformation force of the surrounding rock deformation and acting on the supporting structure or the gravity of the collapsed rock is collectively referred to as the surrounding rock pressure. According to the causes of surrounding rock pressure, it can be divided into the following four types:
(1) Loosening surrounding rock pressure
The rock mass loosened or collapsed due to excavation of the roadway, the pressure directly acting on the structure of the bracket in the form of gravity, appears as a form of pressure load on the surrounding rock.
(2) Deformed surrounding rock pressure
When the support can control the development of the surrounding rock deformation, the pressure generated by the surrounding rock displacement extrusion bracket is called the deformation surrounding rock pressure and the deformation pressure.
(3) Expansion surrounding rock pressure
The surrounding rock expands and the volume of disintegration increases and the pressure on the support is applied, which is called the expansion pressure. The basic difference between the expansion pressure and the deformation pressure is that it is caused by water swelling.
(4) Impact and impact rock pressure
Impact and impact surrounding rock pressure consists of two parts, namely, the pressure generated by the sudden release of the surrounding rock after a large amount of elastic deformation energy is accumulated, and the pressure generated on the roadway support body during the strenuous movement of the overburden on the working face.
2. Main factors affecting surrounding rock pressure
The factors affecting the surrounding rock pressure can be basically divided into two major categories: mining technology factors and geological factors. Among the mining technical factors, the most influential is the mining work situation, that is, the relative space and time relationship between the roadway and the mining face. The geological factors mainly include: the original rock stress state, the surrounding rock mechanical properties, the rock mass structure, the rock composition and cementation state, and the water supply in the surrounding rock.
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