Study On Thermal Effect Of Surrounding Rock In Deep Mining Roadway

In the last ten years,the shallow coal reserves in the middle and east of China have been decreasing,and most of the mines have gradually shifted to deep mining,which will inevitably face the influence of "three high".Therefore,the deep mining roadway support is increasingly becoming the problem of coal mine safety production.In this paper,the single axial compression of the coal rock samples taken from the engineering site is carried out,and the physical and mechanical parameters such as the compressive strength of the coal rock are determined.Then through matching for making similar standard specimens in the laboratory,which structure and mechanical properties and the original rock remain similar and the mechanical characteristic curve is similar to the original rock under the condition of normal temperature,to study the influence of the mechanical properties of coal rock uniaxial compression at different temperatures.At the same time,in order to study the theory of resin anchoring bolt anchorage,in this paper,through the matching with the original medium intensity of coal rock in the laboratory,such as surrounding rock of roadway and through the analysis of the anchoring interface changes in mechanical properties and failure characteristics of surrounding rock,bolt anchorage failure mechanism is determined.The main research results are as follows:(1)By studying the mechanical characteristic curves of sandstone and coal at different temperatures,the whole process of stress and strain curves has four stages:the compaction stage,the elastic stage,the yield stage and the failure stage.The temperature is different,and the characteristics of each curve are different.Under the same temperature condition,the mechanical characteristic curves of the three specimens in each group were also different.(2)With the increase of temperature the peak stress of sandstone gradually reduce.Temperature below 40 ℃ sandstone peak stress at the lower speed faster,and temperature is higher than 40 ℃ peak stress by lesser degree,and peak strain decreases gradually,the elastic modulus decreases gradually,bulk modulus increase gradually.The peak stress of coal specimen increases with the increase of temperature,the peak strain decreases with the increase of temperature,the elastic modulus decreases with the increase of temperature,and the volume modulus decreases with the increase of temperature.(3)Based on the experiment of sandstone and coal in the process of peak stress,peak strain,modulus of elasticity,according to the hypothesis that the weibull distribution,rock stress and strain intensity theory and damage mechanics theory,considering the effect of temperature of hot rock damage constitutive equation is calculated.(4)Based on the ratio of rock uniaxial experiment to determine,then making cement mortar anchorage specimens for sandstone and coal and the influence of different temperature on the anchorage properties of two kinds of surrounding rock was studied.It is shown that,with the increase of temperature,the anchorage properties of sandstone and coal are gradually reduced.Through the comparison of the two surrounding rock media,the strength of the surrounding rock will also have greater anchorage properties for the resin anchoring agent at the same temperature.Although there is some increase in the axial force near the free end,the axial force generally decreases with the anchorage depth.According to the failure form of the anchorage specimens,the falling form of the bolt is mainly manifested as the relative sliding between the anchoring layer and the surrounding rock.When the pull load exceeds the bonding force between the anchorage layer and the surrounding rock,the anchorage layer is pulled out.