With the development of hydraulic technology, the performance of coal mine mechanical support equipment is improved. Support means of single hydraulic prop and hydraulic support for roof support of coal mine roadway. Based on the characteristics of coal seam distribution and industrialization level in China, the support capacity of the former prop is poor, which cannot ensure the safe production of mining personnel, and the number of use is decreasing year by year. The comprehensive performance of hydraulic support is high. Due to the mining cost, the market penetration rate decreases, and it is only used in some support occasions.
The single hydraulic prop has the characteristics of large initial support force, constant working resistance, uniform load bearing, constant increase group resistance reduction, etc., which has been gradually popularized in production practice and become the leading product of coal roadway support at present. Single hydraulic prop is suitable for different coal face, roof condition and coal mine pressure, and can be used with metal hinged roof beam in any face below the dip Angle of coal seam 35°. When the coal mining face with rock burst exists, the three-use valve with large flow can be replaced to meet its support requirements. According to different ways of oil supply (working medium), it can be divided into external oil supply type (external injection type, referred to as "DW type") and internal oil supply type (internal injection type) pillar. The internal injection type has environmental protection advantages, but the production and maintenance costs are high at the same time, so it is restricted in the whole product promotion and the number of use is small.
The single hydraulic prop is restricted by the working environment, which mainly bears two kinds of static load and dynamic load. Static load mainly refers to the load with the same size or small change; With the change of support time or under the influence of any object with accelerated motion, it is a dynamic load. The static load of the working face refers to the weight of the direct roof above the strut (the direct roof is used in caving and mining) and the deformation pressure of the direct roof which is transferred to the strut when the old roof rotates. The dynamic load of the working face is the impact load caused by the direct roof fall of the supporting face and the load caused by the sudden instability of the old roof to the support column. Therefore, the study of static and dynamic characteristics of single hydraulic support as an important index to measure support performance determines the development of coal mine support equipment.
