Controlling Technology Of Roadway Surroundingrock Containing Infilled Joints In Haojinyuan Coal Mine

For underground engineering rocks, shearing processes of joints are subjected to the restriction of surrounding rock duo to the dilation effects, which will increase the normal stress of joint plane and then restrain the dilation effects in turn. Thus, it is reasonable to regard the shearing processes of joints are conducted under constant normal stress(CNS) condition. If joints are filled with geological materials having low mechanical properties, the infilled joints generally become the initial shear failure zone, which will decrease the shear strength of jointed rock significantly. Therefore, understanding the shear behaviors of infilled joints under CNS condition contributes to providing a theoretical basis for the stability evaluation and controlling technology of engineering rock.Having considered several key factors influencing the direct shear test of infilled joints, the thesis developed a numerical method to conduct direct shear test for infilled joints under CNS condition. By performing numerical contrast tests, the difference of shearing behaviors of clean joints under CNL and CNS condition, and the difference of shear failure characteristics between infilled joints and clean joints have been studied. The results showed that the shear failure modes of infilled joints were determined by rock, fillings and their interfaces. The fillings not only decreased the shear strength of joints, but also changed the shear failure modes. With the numerical tests, the influence of both joint waviness and infill ratio on the shear failure characteristics of infilled joints has also been studied. The results showed that the rise of joint waviness was able to increase the shear strength of infilled joints, but the increase of infill ratio would decrease the shear strength significantly. It is worth pointing that when the infill ratio was less than 1.0, the shear strength of infilled joints were mainly determined by fillings, which brought about a little change in shear strength of the joints.By adopting the bolt function of pile element in FLAC3 D, the thesis studied the bolted effects on the shear strength of infilled joints, and then the influence of both infill ratio and bolt installing angle on the shear strength of infiiled joints were analyzed. The results showed that bolts were able to provide extra cohesion and extra normal stress, for which the shear strength of bolted infilled joints was larger than that of infilled joints. The small difference between the bolt installing angle and the specimen slipping angle will be beneficial to the anti-shear ability of bolts.Based on the above studies, the thesis analyzed the deformation failure characteristics of roadway surrounding rock containing infilled joints by numerical method, and then determined the influence rule of both infilled joints position and infill ratio(t/a) on the shearing behaviors. Finally, the controlling technology for roadway surrounding rock containing infilled joints was put forward. The monitoring results of mining pressure showed that the controlling technology was able to ensure the stability of roadway surrounding rock.