The Stability Evaluation Of The Surrounding Rock Of The Inclined Shaft During The Quaternary Water-rich And Thick Sand Layer Segment And Its Supporting Technology

Conducting the research on the stability evaluation and its supporting technology of thesurrounding rock of the inclined shaft during the quaternary water-rich and thick sand layersegment has the important engineering application value for the inclined shaft safe construction inyulin-shenmu mining area and the areas under the similar geological conditions.Based on theconstruction engineering of the II vice inclined shaft in the Xue Mao-tan coal mine, thetheoretical analysis and the field monitoring and numerical simulation were adopted to carry outthe research work. The main conclusions follow:(1)The main factors affecting the surrounding rock deformation for the inclined shaft of theXue Mao-tan coal mine are the groundwater and the sand mechanical parameters and the rocklevel and the construction factors; the surrounding rock of the inclined shaft during the quaternarywater-rich and thick sand layer segment was characterized as unstable rock.(2)The different advanced support mechanical models were built and the computationalanalysis were compared, the results showed that the little pipe shed method which support thesurrounding rock could meet the safety requirements of the advanced support, on the basis of thelittle pipe shed method inserting plate could improve its overall stability.(3)Stress characteristics analysis of the shaft surrounding rock was taken and the controllingvariable method was taken to determine the tensile stress along the axial direction of the shaft, theresults showed that the growth rate of the tensile stress along the axial direction of the shaftdecreases with the increase of the thickness of the wall concrete, while increasing the cohesionbetween the first support and the secondary lining could effectively prevent the occurrence ofcracks along the section direction of the shaft.(4)Based on the theoretical analysis and the engineering analogy method, the design of the support program of the surrounding rock of the inclined shaft during the quaternary water-richand thick sand layer segment was made.FLAC numerical simulation calculations and the fieldtests were adopted to evaluate its support program, the results showed that using the compoundsupporting system which includes the advanced support of the pipe roof–flapper method and ajoint support and the support of secondary lining could effectively control the deformation ofsurrounding rock and meet the security needs.(5)FLAC software was adopted to study the rock deformation law of the inclined shaftacross the water-rich and thick sand layer under the situation of the different stress levels andexcavation step. The calculation results showed that when the stress level increase the two sidesupport should be strengthened, and else, when the inclined shaft pass through the water-rich andthick sand layer the reasonable excavation step should be selected.