Active controllable yielding supporting system and method for underground chamber for stratum supporting

Abstract

The invention discloses an underground chamber active controllable yielding supporting system and method for stratum supporting, and the supporting method comprises the steps: (1) carrying out stress deformation analysis on an underground chamber under a crustal stress working condition, and determining initial deformation data after the chamber is excavated; (2) determining the thickness of the pressure arch, the anchor point position of the tension type pressure arch anchor rod and the displacement Dpoint of the corresponding anchor point; (3) when Dinit exceeds 400 mm, determining the total yielding amount Dyield, the length, the distance and the pre-tensioning force of the tensioning type yielding anchor rod; (4) constructing radial tension type yielding anchor rods and longitudinal and transverse combined steel belts of the radial tension type yielding anchor rods, constructing an anchor-shotcrete supporting layer, and forming a pressure arch anchor-shotcrete supporting system; and (5) determining and constructing a full-section tension type long system anchor rod, and constructing a system anchoring and shotcreting support layer to form a full-section system anchoring and shotcreting support system. By means of the method, the self-bearing capacity of surrounding rock can be improved, surrounding rock deformation is reduced, stability is improved, and meanwhile the excavated volume and the concrete supporting volume are reduced.

Description

technical field [0001] The invention relates to the technical field of rock and soil excavation and support for underground engineering, in particular to an active controllable pressure-yielding support system and method for underground chambers used for stratum support. Background technique [0002] Underground engineering cavern excavation and support technology has a history of hundreds of years, from the early mining method to the later developed tunnel boring machine method (TBM). The two tunneling technologies still exert their respective advantages to meet the engineering needs of different conditions. [0003] As far as the mining method is concerned, before the appearance of steel bars and concrete, after excavating the chamber, wooden supports were erected temporarily, and then the chamber was built with stones to maintain stability; later, the lining was poured with concrete; Considering the lining structure as the load of the collapsed body, the overall structur...

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Problems solved by technology

[0007] The reason may be that, on the one hand, the initiative and timeliness of using anchor bolts to reinforce the surrounding rock of the excavated chamber is insufficient, such as not applying prestress to the strata to control the initial deformation, insufficient joint action of anchor bolts, steel supports and shotcrete, and insufficient anchor bolts. Weak support force of poles does not have controllable yielding deformation capacity, and cannot exert the controllable deformation self-supporting capacity of surrounding rock, resulting in increased risk of construction failure and repair

[0008] On the other hand, the thickness of shotcrete is too large due to rigid support; after the initial anchor shotcrete support, a very thick secondary molded lining (such as 80cm thick lining) is used to passively deal with excessive deformation, resulting in reserved excavation. Large quantity and high cost

[0009] In addition, due to the change of stratum stress, the amount of reserved deformation changes a lot, which often makes the size of the excavation chamber change a lot, which is not conducive to construction.

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