The control principle and technology of “one obstruct and three strengthen” of soft rock roadways below weak aquifers

Aiming at many problems about large deformation of surrounding rock of soft rock roadway below weak aquifers, the transportation roadway of coalface 110207 of Qingshuiying Мine is taken as an object to study a series of research works. Firstly, deformation and failure characteristics are analysised according to the field investigation and measurement. It is clear that there are four weaknesses in the roadway, which are the coexistence of water and high proportion of clay minerals, weak anchorage foundation, weak support resistance diffusion efficiency and weak bearing capacity. Secondly. Theoretical analysis, numerical simulation and field measurement have revealed the failure mechanism of the transportation roadway of coalface 110207, It is believed that the deformation and failure process of roadway surrounding rock under weak aquifer can be divided into three stages: initial deformation, rapid deformation and slow growth. The deformation in the three stages accounts for about 10%, 30% and 60%. The existence of water is an important factor affecting the slow growth of surrounding rock deformation in the later period of this type of roadway. Finally, the control method and principle of “one obstruct and three strengthen” is put forward, that is, appropriate methods are adopted to cut off the contact between water and mudstone, strengthen the anchoring foundation of the bolt and cable, strengthen the diffusion surface of the preload of the bolt cable and enhance the bearing capacity of the roadway surrounding rock, and the corresponding comprehensive control scheme of “cable + net + grouting + spray” is given. The field measurement shows that the surrounding rock fissure is closed to cut off the flow way of water, and the anchorage force of anchor cable is strengthened after grouting.The maximum displacement of the two sides of the roadway is 51.9 mm, and the maximum displacement of the roof and floor is 27.8 mm, which ensures the normal use of the roadway. The problem of large deformation of surrounding rock of soft rock roadway below weak aquifer can be better solved by the research results, and provide a certain reference for the stability control of the same type of roadway. © 2023 Coal Science and Technology. All rights reserved.