CN212225210U

CN212225210U - Shaft structure suitable for weak surrounding rock

Info

Publication number: CN212225210U
Application number: CN202020224022.7U
Authority: CN
Inventors: 张宇弛; 赖勇; 张永进; 戴邦国; 区丽雯; 谢宇琦
Original assignee: Zhejiang Design Institute of Water Conservancy and Hydroelectric Power
Current assignee: Zhejiang Water Resources And Hydropower Survey And Design Institute Co ltd
Priority date: 2020-02-28
Filing date: 2020-02-28
Publication date: 2020-12-25
Anticipated expiration: 2030-02-28

Abstract

The utility model discloses a shaft structure suitable for weak country rock, shaft wall of a well outside-in is equipped with preliminary bracing, outer lane concrete, hoop expansion joint, gate slot concrete and two steel ladders that run in proper order. The outer contour of the cross section of the vertical shaft is in a double-arc shape, and the inner contour is in a convex shape; surrounding rocks are mutually extruded on the arc-shaped beam, so that the external soil pressure load generated by the sliding of the surrounding rocks into the vertical shaft is reduced, the soil arch effect is fully utilized, and the stability of the well wall in the construction period is improved; the circular arc-shaped profile can fully exert the characteristic of good compression resistance of concrete, and the safety of the shaft structure in the operation period is improved; the circumferential expansion joint is arranged between the outer ring concrete and the gate slot concrete, so that the influence of the deformation of the outer ring concrete-surrounding rock system on the gate slot structure is reduced, and the reliability of the gate in the operation period is improved; set up two race steel ladders in door groove concrete upper reaches side, the downstream side sets up the air vent, make full use of door groove concrete space, make things convenient for personnel to overhaul.

Description

Shaft structure suitable for weak surrounding rock

Technical Field

The utility model relates to a shaft structure especially relates to the dark shaft structure of major diameter suitable for weak country rock geological conditions.

Background

In long-distance water delivery engineering, in order to meet the normal operation and maintenance of a water delivery system, a water taking gate, an accident maintenance gate, a flow control gate and other hydraulic buildings which relate to a large-diameter deep shaft are required to be arranged along a water delivery tunnel. The excavation cross section of the vertical shaft usually adopts a rectangular structure, the primary support of the well wall after excavation adopts an anchor spraying system so as to ensure the construction safety in the excavation period, and then reinforced concrete lining is carried out.

The rectangular section has the characteristics of simple excavation and adaptation to a door slot form, but the unit length arch effect of the rectangular section is poor, the plastic deformation resistance is not strong, and for a vertical shaft arranged in a weak surrounding rock geological condition, the phenomena of sprayed concrete cracking, well wall deformation, water seepage and the like which threaten the safety of a construction period can occur on the well wall after primary support. The deformation of the well wall can invade the reinforced concrete lining space, so that the thickness of the concrete lining is insufficient. The plastic deformation of the weak surrounding rock can cause the deformation of the gate slot structure, and the normal opening and closing of the gate are influenced.

The deformation after preliminary bracing of the well wall can be reduced by adopting the technical means of 'strong bracing' such as increasing the thickness of sprayed concrete, increasing the length of anchor rods, reducing the space between the anchor rods and the like, but for a large-diameter deep shaft, 'strong bracing' can greatly increase the engineering quantity and investment, prolong the construction period, and cannot solve the problem of concrete lining cooperative deformation caused by plastic deformation of surrounding rock.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems existing in the prior art, the utility model provides a cross section that the atress is reasonable, stable in structure, convenient maintenance is "protruding in the excircle" shape major diameter deep shaft structure. On one hand, reasonable excavation profiles and preliminary bracing modes are selected, the stress form of the shaft wall of the vertical shaft is optimized, and the stability and the safety of the shaft wall in the construction period are improved. On the other hand, the circumferential expansion joint is arranged in the reinforced concrete lining to isolate the outer ring concrete from the door groove concrete, and the deformation of the surrounding rock-outer ring concrete system does not cause the deformation of the door groove structure. Meanwhile, the space in the concrete of the door slot is fully utilized, and a vertical overhaul channel is arranged.

The utility model adopts the technical proposal that: the vertical shaft structure is suitable for weak surrounding rocks, and the vertical shaft wall of a well sequentially comprises a primary support system, outer ring concrete, circumferential expansion joints, door slot concrete and a double-running steel ladder from outside to inside. The primary support system adopts an anchor-spraying combined support system, and comprises a system anchor rod, sprayed concrete and a reinforcing mesh, wherein the reinforcing mesh is hung after the sprayed concrete is finished, and the exposed part of the system anchor rod is bent and then welded with the reinforcing mesh. And after primary support, carrying out reinforced concrete lining, wherein the circumferential expansion joint divides the reinforced concrete lining into two parts, namely outer ring concrete and door slot concrete, the outer ring concrete is annular and is in a double-arc-shaped outline, a cooperative deformation system is formed with surrounding rocks, the outer ring concrete double-arc-shaped outline is formed by splicing four sections of arcs, and the radius, the angle and the circle center position of each section of arc can be adjusted to meet the size requirement of the door slot. The profile is "protruding" font in the gate slot concrete, and the protruding position of upstream side is provided with the two steel ladders that run of perpendicular to rivers direction, and two steel ladders that run extend the water delivery tunnel top after, two steel ladder bottoms of running are provided with the contraction type cat ladder, and the personnel get into the inside access door slot structure of tunnel through the cat ladder. And a vent hole is arranged at the downstream side of the concrete of the gate slot.

In the geological conditions of poor stability of surrounding rocks such as loose, weak and broken surrounding rocks of the vertical shaft, the primary support system is provided with an annular steel arch, the annular steel arch is matched with the double-arc-shaped outline of outer ring concrete, and the steel arch and a system anchor rod form an integral structure through welding additional tie bars. In the geological condition that underground water moves frequently, a system drain hole is arranged at a large-area water seepage position on the wall of a vertical shaft well of the primary support system, a drain pipe is externally connected to the wall of the well, and a reverse filter bag is arranged at the tail end of the drain pipe to prevent the pipeline from being blocked.

And after the lining of the reinforced concrete of the outer ring of the shaft is finished, the surrounding rock is reinforced through consolidation grouting, so that leakage is reduced.

The circumferential expansion joint can be 2-10 cm wide, and a low-foaming plastic foam plate is filled in the expansion joint.

The utility model has the advantages that:

1) the stability of the well wall in the excavation period is improved. When the surrounding rock slides into the vertical shaft to generate an external soil pressure load, the rock masses have mutual extrusion action on the arc-shaped beams in addition to the frictional resistance between the rock masses on the sliding surface to generate a closed arch ring structure, so that the instability in the vertical shaft can be prevented, the stability is better, and the lateral displacement can be effectively controlled. Meanwhile, the circular arc-shaped section fully utilizes the soil arch effect, and the soil pressure acting on the supporting structure is reduced.

2) The structural safety during operation is improved. The soil pressure is vertical to the wall of a vertical shaft well, the soil pressure is linearly increased along with the increase of the depth, no concentrated force exists, the acting load can be converted into the internal pressure of a lining supporting structure by the arc-shaped section, the characteristic of good compression resistance of concrete is fully exerted, and the stability of the structure is obviously improved.

3) The investment is saved, and the construction progress is accelerated. Compared with a conventional rectangular section, the arc-shaped section has a smaller section area, and the earth and stone excavation amount and the concrete consumption are saved.

4) The reliability of the gate during operation is improved. The circumferential expansion joint reserves a space for the deformation of the surrounding rock-outer ring concrete system, so that the plastic deformation of the weak surrounding rock does not influence the concrete structure of the door slot.

5) The lining internal space is fully utilized, and the traffic condition is well overhauled. The two steel ladders that run set up between double circular arc type profile and rectangle gate slot, make full use of the rectangle gate slot long limit and need the "invalid" space that the concrete backfilled originally between the profile circular arc, realized personnel simultaneously and got into the water delivery tunnel and overhauld.

Drawings

Fig. 1 is a vertical sectional view of the shaft of the present invention;

FIG. 2 is a cross-sectional view of the excavation and primary support system of the present invention;

FIG. 3 is a cross-sectional view of the lining of the present invention;

FIG. 4 is a cross-sectional view of the maintenance platform of the present invention;

FIG. 5 is a detailed view of the steel arch of the present invention;

fig. 6 is a detailed view of the water discharging pipe of the utility model.

In the figure: 1-outer ring concrete; 2, circumferential expansion joint; 3, door slot concrete; 4-double running steel ladder; 5, a water delivery tunnel; 6, overhauling the platform; 7, system anchor rod; 8-annular steel arch frame; 8 a-spraying concrete and reinforcing mesh; 9-consolidation grouting hole; 10-a vent hole; 11-double circular arc profile; 11 a-arc I; 11 b-arc II; 11 c-arc III; 11 d-arc IV; 12-convex inner contour; 13-additional lacing wire; 14-a drain pipe; 15-reverse filtration package; 16-system drain hole.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

As shown in the accompanying drawings 1-4, the utility model is suitable for a shaft structure of weak country rock, shaft wall of a well outside-in includes primary support system, outer lane concrete 1, hoop expansion joint 2, gate slot concrete 3 and two running steel ladders 4 in proper order, and the shaft bottom is water delivery tunnel 5, and the top is for overhauing platform 6. The cross section of outer ring concrete 1 is double circular arc profile 11, by circular arc I11a, circular arc II 11b, circular arc III 11c, these four sections circular arcs of circular arc IV 11d are spliced and are constituteed, can adjust the radius of every section circular arc, angle and centre of a circle position, in order to satisfy the gate slot size requirement, the hoop expansion joint 2 sets up between outer ring concrete 1 and gate slot concrete 3, gate slot concrete 3 designs for profile 12 in the "protruding" font, set up the two steel ladders 4 that run of perpendicular to rivers direction in the space of "protruding" play of upstream side, the realization gets into water delivery tunnel 5 from maintenance platform 6 and overhauls, gate slot concrete 3 downstream side sets up air vent 10.

As shown in fig. 2 and 5, the primary support system comprises a system anchor rod 7, a circumferential steel arch 8 and a sprayed concrete and reinforcing mesh 8a, the construction of the sprayed concrete and reinforcing mesh 8a is firstly carried out, the circumferential steel arch 8 is installed at the inner side, the system anchor rod 7 is finally arranged, the exposed part of the end part of the system anchor rod 7 is bent and welded with the circumferential steel arch 8. The specification of the anchor rod 7 of the system is phi 25@1.5m multiplied by 1.5m, the specification of the reinforcing mesh is phi 8@15cmx15cm, the thickness of the sprayed concrete is 20cm, and supporting parameters can be adjusted according to the softness and the crushing degree of surrounding rocks. The annular steel arch 8 is matched with the double-arc-shaped profile 11 of the outer ring concrete 1, the cooperative supporting effect is fully exerted for enhancing the cooperative capability of the annular steel arch 8 and the system anchor rod 7, and the annular steel arch 8 and the system anchor rod 7 are welded into an integral structure through an additional tie bar 13.

As shown in the attached figure 6, 4.5m deep system drain holes 16 are arranged at large-area water seepage positions on the wall of a vertical shaft well, the row spacing is 2m multiplied by 2m, the system drain holes 16 are arranged towards the 5% gradient in the well, a 50cm PVC drain pipe 14 is externally connected to the wall of the well, and a reverse filter bag 15 is arranged at the end part of the PVC drain pipe 14, so that underground water can be collected to the system drain holes 16 conveniently, and meanwhile, the system drain holes 16 cannot be blocked.

The double-arc structure is beneficial to exerting the characteristic of strong compression resistance of concrete, and grouting is carried out through the consolidation grouting holes 9 so as to reinforce the weak surrounding rock, ensure the elastic resistance of the surrounding rock, improve the integrity of the surrounding rock and reduce leakage.

The shaft structure sets up the contraction type cat ladder 4 bottoms at two running steel ladders, and length is not less than the drill way height to set up safety rope, guarantee personnel safety from top to bottom.

The above embodiments are described in connection with the accompanying drawings, but it should not be understood as a limitation to the scope of the present invention, and it should be noted that, for those skilled in the art, the technical solutions obtained by equivalent replacement or equivalent transformation without departing from the concept of the present invention, and all of them belong to the protection scope of the present invention.

Claims

1. Shaft structure suitable for weak country rock, its characterized in that: the shaft wall of the vertical shaft structure sequentially comprises a primary support system, outer ring concrete, an annular expansion joint, door groove concrete and a double-running steel ladder from outside to inside; the primary support system adopts an anchor-spraying combined support system and comprises a system anchor rod, sprayed concrete and a reinforcing mesh, the reinforcing mesh is hung after the sprayed concrete is finished, and the exposed part of the system anchor rod is bent and then welded with the reinforcing mesh; after primary support, reinforced concrete lining is carried out, the circumferential expansion joint divides the reinforced concrete lining into two parts, namely outer ring concrete and door slot concrete, the outer ring concrete is annular and has a double-arc-shaped outline, a cooperative deformation system is formed with surrounding rocks, and the inner outline of the door slot concrete is in a convex shape; a double-running steel ladder vertical to the water flow direction is arranged at the convex part at the upstream side.

2. A shaft structure adapted for weak surrounding rock according to claim 1, characterized in that: the double-arc-shaped profile of the outer ring concrete is formed by splicing four sections of arcs, and the requirements on the size of the gate slot are met by adjusting the radius, the angle and the circle center position of each section of arc.

3. A shaft structure adapted for weak surrounding rock according to claim 1, characterized in that: the primary support system is provided with an annular steel arch, the annular steel arch is matched with the double-arc-shaped profile of the outer ring concrete, and the annular steel arch and the system anchor rod form an integral structure through welding additional tie bars.

4. A shaft structure adapted for weak surrounding rock according to claim 1, characterized in that: the primary support system is provided with system drain holes at a large-area water seepage position on the wall of a vertical shaft well, the system drain holes are externally connected with a drain pipe on the wall of the shaft well, and the tail end of the drain pipe is provided with an anti-filter bag to prevent pipelines from being blocked.

5. A shaft structure adapted for weak surrounding rock according to claim 1, characterized in that: and after the outer ring concrete lining is finished, the surrounding rock is reinforced through consolidation grouting, so that leakage is reduced.

6. A shaft structure adapted for weak surrounding rock according to claim 1, characterized in that: and a low-foaming plastic plate is filled in the circumferential expansion joint.

7. A shaft structure adapted for weak surrounding rock according to claim 1, characterized in that: and a vent hole is arranged at the downstream side of the gate slot concrete.

8. A shaft structure adapted for weak surrounding rock according to claim 1, characterized in that: the bottom of the double-running steel ladder is provided with a retractable ladder stand.

9. A shaft structure suitable for weak surrounding rock according to claim 4, characterized in that: the system drain holes are drilled towards a 5% grade in the well.

10. A shaft structure adapted for weak surrounding rock according to claim 1 or 6, characterized in that: the width of the circumferential expansion joint is 2-10 cm.