Study on key control technology of floor heave in soft rock roadway

In view of the problem of the floor heave deformation in the weakly cemented soft rock roadway in western China, the 21103 horizontal entryway of Yili No.4 Mine in Xinjiang was used as the engineering background, the deformation characteristics of surrounding rock and the mechanism of floor heave were analyzed through the monitoring and site observation of surrounding rock deformation. The results show that the weak cemented soft rock roadway in Yili No.4 Mine is a weak cemented soft rock roadway. It is characterized by low lithological strength, weak cementation, easy exposure to weathering, easy disintegration in water and large excavation deformation,etc. The key influencing factors are floor lithology and structural state, rock stratum stress, support strength and hydraulics. According to the analysis of the causes of floor heave, a combined support technology of bolt beam, bolt, mesh shot-crete and pouring concrete is proposed for roadway floor. Field monitoring shows that the floor heave velocity is less than that of roof and two sides within 10 days before excavation, and the floor heave develops at a relatively stable speed within 10 days to 40 days. After 50 d, the floor heave remained basically stable, indicating that the combined support structure of the floor played a good role. The support technology can effectively control the deformation of surrounding rock.