## 5 Conclusions  
This study was focused on floor heave evolution and its restriction in gob-side entry retaining. Floor heave control with anti-shear pile technology was studied. Numerical simulation by ANSYS 17.2 software was used for the stress-strain analysis of the surrounding rock. As a result, a floor heave mechanism was proposed. Based on the analysis of the floor heave causes, perspective schemes for immediate floor reinforcement were proposed and a study of their effectiveness was conducted. Based on the results of this investigation, the following conclusions can be drawn:  
(1) The transformation of high vertical stresses, which arise in the entry floor underneath the filling wall and coal seam body, into horizontal stresses starts the floor heave process. Increased vertical stresses under the filling wall and coal seam body cause the dilatancy expansion of rocks in the horizontal direction. As a result, a zone of horizontal compression underneath the entry span occurs. Rocks within this zone, in the process of dilatancy expansion to relieve stress, displace towards the entry cavity. This leads to the delamination of rocks in the vertical direction and uplift of the entry contour. Between the zone of rock uplift under the entry span and the zones of rock subsidence underneath the filling wall body and coal seam body, high-shear zones arise, in which vertical stresses are transformed into horizontal ones. The rock failure in these zones complicates the floor heave mechanism described above. (2) The ways to control floor heave are (1) restricting stress transformation in the entry floor; (2) increasing the bearing capacity of the immediate floor to counteract rock dilatation and delamination. A floor heave control method with anti-shear pile installation was proposed. The numerical simulation results confirmed the efficiency of pile installation. This makes it possible to significantly reduce the floor heave and the size of the zone of horizontal post-peak strain. As a result of numerical simulation, the most effective scheme (2 pile 5+2) was found. A technical and economic comparison of different types of piles was carried out to find the most economical and simple solutions for the practical  
Figure 18: Design of support scheme. implementation of this scheme. Analysis of the numerical simulation results and the cost comparison of different types of piles shows that filling piles are the most effective ones. The cost of filling piles is more than 3.5 times less than the steel pile cost. In addition, the installation of filling piles does not require significant labor costs; the weight of the reinforcement used in this scheme is less than the weight of tubes in analog piles, which also reduces transportation costs. The implementation of the proposed floor heave control method with anti-shear piles leads to a significant reduction in heaving in gob-side entry retaining. The results of this study can be used to design a support system in gob-side entry retaining. (3) Anti-shear pile technology is at the stage of elaboration and justification of parameters. In situ tests are planned for the future. Therefore, the above-described effect is based only on the results of numerical simulation so far. Further research will aim to study the effectiveness of the proposed floor heave control method in situ in coal mines. The best design for filling piles will also be found. Conceptualization, I.S. and S.S.; methodology, I.S. and O.L; software, I.S. and K.S. ; validation, I.S., K.S., K.Z. and A.Z. ; formal analysis, S.S.; investigation, I.S. ; resources, K.Z. and A.Z. ; writing--original draft preparation, I.S. ; writing--review and editing, K.S. and S.S.; visualization, O.L; supervision, I.S. ; project administration, I.S. ; funding acquisition, K.S., K.Z. and A.Z. All authors have read and agreed to the published version of the manuscript. This research received no external funding.