Treatment method for running metro underground excavation station ballast bed upheaval

Abstract

The invention discloses a treatment method for a ballast bed upheaval of an underground excavation station of an operating metro. A plurality of anchoring holes and drainage holes are formed in a ballast bed upheaval affected area, anchor rods are arranged in the anchoring holes, grouting is conducted in the anchoring holes, and finally the ballast bed is anchored through the formed anti-floating anchor rods. The anchor rod comprises a twisted steel bar for prestressed concrete, the diameter of the twisted steel bar for prestressed concrete is 40 mm, a conical centering loader is connected to the twisted steel bar for prestressed concrete, and a spiral stirrup is arranged at the position, corresponding to a ballast bed, of the top end of the twisted steel bar for prestressed concrete. And at least two water-stopping rings which expand when meeting water are arranged on the twisted steel for the prestressed concrete and correspond to the position between the ballast bed and the backfill layer and the position between the backfill layer and the secondary lining concrete. The track ballast bed can be effectively anchored through the formed anti-floating anchor rod, so that the track ballast bed, a station bottom plate and a stratum rock mass are connected into a whole, and the problems that the bottom of the ballast bed is void in the later period of subway operation, a large amount of water is drained in a station for a long time, and the operation safety risk is large can be effectively solved.

Description

Technical Field

[0001] The invention relates to a method for treating the uplift of the roadbed of an operating subway dark-cut station, and belongs to the technical field of treating the uplift disease of the track roadbed of an operating subway dark-cut station. Background Art

[0002] In the construction of rail ballast heave disease treatment in operating subway underground excavation stations, the traditional overall technical solution of "draining water to reduce pressure, reinforcing the bottom, and returning water flow to the channel" is used for treatment. However, this traditional treatment method still has the following construction difficulties:

[0003] (1) Long-term pressure relief and water discharge result in excessive daily drainage volume at operating stations, frequent replacement of drainage equipment, and groundwater loss;

[0004] (2) Although the hollow parts at the bottom of the ballast have been reinforced, as groundwater continues to carry the reinforced soil out of the body, the quality of the reinforced body at the bottom of the ballast still poses a great risk, making it difficult to ensure the safety of subsequent operations. Summary of the invention

[0005] In view of the above-mentioned defects existing in the prior art, the present invention provides a new method for controlling the uplift of the roadbed in an operating subway underground excavation station, which can solve the problems of hollowing out of the bottom of the roadbed in the later stage of subway station operation, long-term large-volume drainage in the station, and high operational safety risks.

[0006] The present invention is realized by the following technical scheme: a method for treating the uplift of the roadbed of an operating subway underground excavation station, characterized in that: a plurality of anchor holes and drainage holes are arranged in the area affected by the uplift of the roadbed, anchor rods are arranged in the anchor holes, grouting is poured into the anchor holes, and finally the roadbed is anchored by the formed anti-floating anchor rods; the anchor rods include a PSB1230 grade prestressed concrete threaded steel bar with a diameter of 40 mm, a conical centering load bearing device is connected to the prestressed concrete threaded steel bar, a spiral stirrup is arranged at the top of the prestressed concrete threaded steel bar corresponding to the position of the roadbed, and two water-stopping water-swelling water-stopping rings are arranged on the prestressed concrete threaded steel bar at least at the position corresponding to the position between the roadbed and the backfill layer and the position between the backfill layer and the secondary lining concrete;

[0007] The steps include:

[0008] (1) Construction of drainage holes: Use a 40mm diameter water drill to drill holes at the control points of the drainage holes, with a depth of 1.5-2.5m, until the primary support layer under the ballast is penetrated. After the drainage holes are drilled, install a 28mm diameter galvanized steel pipe and a pressure relief valve to divert groundwater to the drainage ditch. After the water pressure stabilizes and the ballast no longer changes, stop drilling holes to drain water after one week of observation.

[0009] (2) Anchor hole construction: After the hydraulic pressure release is completed and the roadbed is stable, the anchor hole construction begins. A 150mm diameter drilling rig is used to drill the hole. The drilling depth of the anchor hole is 5m. After the drilling is completed, the anchor rod is slowly inserted into the hole.

[0010] (3) Anchor grouting: After the anchor is installed, grouting is carried out. The grouting pressure is controlled at 0.5-2.5Mpa. The grouting material is a high-flow ultra-early strength underwater anti-dispersion grouting material. The grouting method is the bottom grouting method. The anchor grouting should be carried out under the condition that the drainage hole is unobstructed;

[0011] (4) Anchor bolt locking: clean the anchor end plate and install it on the anchor bolt and anchor it with a nut;

[0012] (5) Grouting of drainage holes: CGM-340 ultrafine cement grouting is performed on the drainage holes with a grouting pressure of 0.3-0.4 MPa. After the grouting is completed, the drainage holes are sealed.

[0013] In the present invention, the anti-floating anchor rod formed can effectively anchor the track bed, so that the track bed, station floor and stratum rock mass are connected as a whole, which can effectively solve the problems of the bottom of the track bed being hollowed out in the later stage of subway operation, long-term large-volume drainage in the station, and high operational safety risks. By setting a water-stopping water-swelling water-stopping ring on the prestressed concrete threaded steel bar, the gap between the track bed and the backfill layer, and between the backfill layer and the structure can be squeezed to form a watertight plastic colloid, which effectively stops water. By using high-flow ultra-early strength underwater anti-dispersion grouting material, it can meet the operation under water conditions and can quickly play the role of anchoring the track bed. The conical centering load-bearing device can ensure the verticality of the anchor rod, and it can replace the traditional steel cage in the form of multiple main bars and stirrups when combined with the prestressed concrete threaded steel bar. The spiral stirrups arranged at the upper end of the prestressed concrete threaded steel bar can make the anchor rod more firmly combined with the surrounding concrete and track bed, thereby improving the anchoring effect of the anchor rod.

[0014] Furthermore, the high-flow ultra-early-strength underwater anti-dispersion grouting material has a 4-hour compressive strength of 40Mpa and a 28-day compressive strength of 65Mpa. With a 4-hour compressive strength of 40Mpa, it can play the role of anchoring the roadbed in a short time.

[0015] Furthermore, a water-stopping water-swelling water-stopping ring is arranged on the threaded steel bar for prestressed concrete at a position corresponding to the stratum gap water. By arranging the water-stopping water-swelling water-stopping ring at a position corresponding to the stratum gap water, water stopping can be effectively performed.

[0016] Furthermore, to ensure the anchoring effect, the spacing of the anchor holes arranged along the longitudinal direction of the ballast bed is 5m.

[0017] Furthermore, in order to ensure that the grouting slurry is densely filled, when grouting the drainage hole, the grouting is continued after the drainage hole is blocked until the slurry overflows from the next drainage hole, and the grouting of the hole is completed.

[0018] Furthermore, in order to meet the requirements of underground underwater corrosion protection, the exterior of the prestressed concrete threaded steel bar is provided with an anti-corrosion coating, which is epoxy resin and has a thickness of ≥300um.

[0019] Furthermore, in order to effectively stop water, the thickness of the water-stopping ring that expands when exposed to water is 20 mm, and the maximum expansion rate is 250%-550%.

[0020] Furthermore, the diameter of the conical centering carrier is 110 mm and the height is 120 mm; the conical centering carrier is made of PE insulating material.

[0021] The beneficial effects of the present invention are as follows: the method of the present invention is simple and easy to construct. The anti-floating anchor rods formed can effectively anchor the track bed, so that the track bed, station floor and stratum rock mass are connected as a whole, which can effectively solve the problems of hollowing out of the bottom of the track bed in the later stage of subway operation, long-term large-volume drainage in the station, and high operational safety risks. There are many construction restrictions in subway operating stations. In view of the special environment, the present invention adopts an anchor rod structure with a single prestressed steel bar combined with a conical centering load-bearing device to replace the traditional steel cage in the form of multiple main bars and stirrups. The structural design is simple, the anchoring performance is reliable, and the requirements for anchoring the track bed can be met. In addition, the present invention is light in weight and does not require the use of large machinery for lifting operations. Only manual labor is required for the installation of anchor rods. It has good operability and is convenient for construction operations in the operating subway environment. High-flow ultra-early-strength underwater anti-dispersion grouting material is used to grout the anchor rod holes, which has good water blocking effect and high strength, and can meet It can operate under sufficient water conditions, and its 4-hour compressive strength is 40Mpa, which can play the role of anchoring the roadbed in a short time; by arranging a water-stopping water-swelling water-stopping ring on the prestressed concrete threaded steel bar, an impermeable plastic colloid can be formed at the position of the gap water to effectively stop water; by arranging a conical centering load-bearing device on the prestressed concrete threaded steel bar, the verticality of the anchor rod can be effectively guaranteed; the spiral stirrups arranged on the upper end of the prestressed concrete threaded steel bar can make the anchor rod more firmly combined with the surrounding concrete and roadbed, thereby improving the anchoring effect of the anchor rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the planar arrangement of the anchor holes and the drainage holes in the present invention in a specific implementation manner;

[0023] Figure 2 yes Figure 1 A magnified schematic diagram of part A;

[0024] Figure 3 yes Figure 1A magnified schematic diagram of part B;

[0025] Figure 4 is a cross-sectional schematic diagram of the anchor arrangement in the present invention in a specific implementation manner;

[0026] Figure 5 yes Figure 4 An enlarged schematic diagram of the anchor rod in FIG.

[0027] Figure 6 yes Figure 5 A magnified schematic diagram of the upper middle part;

[0028] Figure 7 yes Figure 5 Middle CC cutaway diagram;

[0029] Figure 8 is a front view of the tapered centering carrier of the present invention;

[0030] Fig. 9 is a top view of the tapered centering carrier of the present invention;

[0031] In the figure, 1. anchor rod, 2. ballast bed, 3. backfill layer, 4. secondary lining concrete, 5. primary support profile, 6. anchor hole, 7. conical centering load-bearing device, 8. water-stop ring that expands when exposed to water, 9. spiral stirrups, 10. prestressed tendon nuts, and 11. anchor end plate. DETAILED DESCRIPTION

[0032] The present invention will be further described below by way of non-limiting embodiments and in conjunction with the accompanying drawings:

[0033] As shown in the attached drawings, a method for controlling the uplift of the roadbed in an operating subway underground station is provided, which comprises setting a plurality of anchor holes and drainage holes in the area affected by the uplift of the roadbed, setting anchor rods 1 in the anchor holes, pouring grout into the anchor holes to form anti-floating anchor rods, and anchoring the roadbed by the formed anti-floating anchor rods.

[0034] The anchor rod 1 adopts a PSB1230 grade prestressed concrete threaded steel bar 1-1 with a diameter of 40mm. The design tensile strength fpy of the prestressed concrete threaded steel bar 1-1 is ≥900Mpa. The prestressed concrete threaded steel bar 1-1 adopts grade II anti-corrosion, and an anti-corrosion coating is arranged on the outside. The anti-corrosion coating adopts epoxy resin with a thickness of ≥300um. The top of the prestressed concrete threaded steel bar 1-1 is provided with a spiral stirrup 9 with a diameter of 10mm@50, and the height of the spiral stirrup 9 is consistent with the thickness of the roadbed 2. The anchor rod 1 is capped with a square anchor end plate 11 with a thickness of 10mm and a side length of 250mm. A Φ44mm circular hole is arranged in the middle of the anchor end plate 11, and a Φ40 prestressed steel bar nut 10 is used to tighten the top. A conical centering bearing 7 is connected to the prestressed concrete threaded steel bar 1-1. The diameter of the conical centering bearing 7 is 110 mm and the height is 120 mm. The conical centering bearing 7 is made of PE insulation material. A Φ40 fine rolling thread matching thread is set at the center of the conical centering bearing 7. The conical centering bearing 7 can be screwed on the prestressed concrete threaded steel bar 1-1. Three openings are evenly spaced at the edge of the conical centering bearing 7. The three openings are convenient for the flow of grouting slurry. A water-stopping water-swelling water-stopping ring 8 is set on the prestressed concrete threaded steel bar 1-1. At least two water-stopping water-swelling water-stopping rings 8 are set at the positions corresponding to the position between the roadbed 2 and the backfill layer 3 and the position between the backfill layer 3 and the second lining concrete 4. In order to ensure the water-stopping effect, a water-stopping water-swelling water-stopping ring 8 can be set at the corresponding position on the prestressed concrete threaded steel bar 1-1 according to the position of the gap water detected in the anchor hole 6. The water-stopping water-swelling water-stopping ring 8 is an existing technology, which adopts a high molecular inorganic water-absorbing and swelling material and rubber. The thickness of the water-stopping water-swelling water-stopping ring 8 is preferably 20mm, and the maximum expansion rate is 250%-550%. The water-stopping water-swelling water-stopping ring 8 can squeeze the gap between the roadbed and the backfill layer, and between the backfill layer and the structure to form a watertight plastic colloid when it encounters water, which can effectively stop water.

[0035] The specific construction includes the following steps:

[0036] (1) Before construction, use a total station to measure the control points of the drainage holes and anchors, spray paint and mark them. After the retest line is qualified, use a steel ruler and survey line to lay out the positions on the spot to ensure that the displacement deviation of the pile hole center is less than 50mm. The layout of the anchor holes and drainage holes is as shown in the attached figure. Figure 1-Figure 3 As shown, M1-M55 are anchor holes and X1-X20 are drainage holes.

[0037] (2) Drain hole construction:

[0038] A 40mm diameter water drill is used to drill holes at the control point of the drainage hole, with a depth of 1.5-2.5m, until the primary support layer at the bottom of the ballast 2 is penetrated. After the drainage hole is drilled, a 28mm diameter galvanized steel pipe and a pressure relief valve are installed to divert groundwater to the drainage ditch to prevent groundwater from flowing to the rails after pressure relief and affecting train operations. After the water pressure is stable and the ballast no longer changes, stop drilling holes to drain water after one week of observation. The actual number of drainage holes can be adjusted at any time according to automated monitoring.

[0039] (3) Anchor hole construction:

[0040] After the water pressure drainage is completed and the roadbed is stable, the construction of anchor holes will begin. A 150mm diameter drilling rig will be used to drill the holes. The drilling depth of the anchor holes is 5m, and the spacing between the anchor holes arranged longitudinally along the roadbed is 5m.

[0041] The hole spacing error of the anchor rod in the horizontal and vertical directions should not be greater than 100mm, and the drill bit diameter should not be less than 3mm of the designed drilling diameter; the deviation rate of the drilling axis should not be greater than 2% of the anchor rod length; the technical personnel should measure and calibrate the axis of the drilling tool to make it consistent with the direction of the center axis of the anchor hole before drilling the hole.

[0042] After drilling is completed, slowly insert the anchor rod with the water stop strip and conical centering carrier installed into the hole. If resistance is encountered, do not force it in. Pull the anchor rod back appropriately and then insert it again. If it still cannot be lowered after repeated attempts, find the cause and remove the anchor rod and reinsert it if necessary.

[0043] (4) Anchor grouting:

[0044] After the anchor rod is installed, grouting is performed. The grouting pressure is controlled at 0.5-2.5Mpa, and the grouting material adopts high-flow super-early-strength underwater anti-dispersion grouting material. The 4-hour compressive strength of the grouting material is 40Mpa, and the 28-day compressive strength is 65Mpa. High-flow super-early-strength underwater anti-dispersion grouting material is a prior art and can be purchased. The grouting material used in this embodiment is a self-compacting concrete high-strength non-shrinkage grouting material produced by Qingdao Xinrunde Energy-saving New Building Materials Co., Ltd. It is a high-flow super-early-strength underwater anti-dispersion grouting material. The grouting material has good water blocking effect and high strength, can meet the operation under water conditions, and has a 4-hour compressive strength of 40Mpa, which can play the role of anchoring the roadbed in a short time. The grouting method is the bottom grouting method: the grouting hole of the grouting pipe is inserted 100-200mm from the bottom of the hole, and the injected slurry gradually returns to the hole mouth from the bottom of the hole. The grouting is stopped after overflowing from the hole mouth; after grouting, the rod body shall not be hit at will, and heavy objects shall not be hung on the rod body; the grouting slurry shall be stirred evenly, used as it is stirred, and used up before the initial setting; stones and debris shall be strictly prevented from mixing into the slurry. Grouting should be carried out under the condition that the drainage hole is unobstructed.

[0045] (5) Anchor rod locking: Clean the anchor end plate 11 and install it on the anchor rod and use the nut 10 to anchor and lock it.

[0046] (6) Grouting of drainage holes:

[0047] CGM-340 ultrafine cement grouting is carried out on the drainage holes, and the grouting pressure is 0.3-0.4Mpa. After the grouting is completed, a special plugging needle is used to plug the drainage holes. During the grouting process, the monitoring of the roadbed monitoring points should be strengthened to prevent the secondary lifting of the roadbed. If it is found that the pressure fails to meet the requirements or the amount of slurry increases suddenly during grouting, the grouting should be stopped to prevent the occurrence of slurry leakage and slurry leakage. In order to ensure that the grouting slurry is filled densely, the grouting is continued after the drainage hole is blocked until the slurry overflows from the next drainage hole, and the grouting of the hole is completed.

[0048] The method of the invention is simple, practical, and operable, and can better connect the track bed, station floor, and stratum rock mass into a whole, and can effectively solve the problems of hollowing out of the bottom of the track bed in the late operation period, long-term large-volume drainage in the station, and high operational safety risks.

[0049] The other parts of this embodiment are all prior art and will not be described in detail here.

Claims

1. A method for treating the uplift of the roadbed in an operating subway underground excavation station, characterized by: A plurality of anchor holes and drainage holes are arranged in the area affected by the ballast bed uplift, anchor rods are arranged in the anchor holes, grouting is poured into the anchor holes, and finally the ballast bed is anchored by the formed anti-floating anchor rods; the anchor rod comprises a PSB1230 grade prestressed concrete threaded steel bar with a diameter of 40 mm, a conical centering load bearing device is connected to the prestressed concrete threaded steel bar, a spiral stirrup is arranged at the top end of the prestressed concrete threaded steel bar corresponding to the ballast bed position, and two water-stopping water-expanding water-stopping rings are arranged on the prestressed concrete threaded steel bar at least at the position corresponding to the position between the ballast bed and the backfill layer and the position between the backfill layer and the secondary lining concrete; The steps include: (1) Construction of drainage holes: Use a 40mm diameter water drill to drill holes at the control points of the drainage holes, with a depth of 1.5-2.5m, until the primary support layer under the ballast is penetrated. After the drainage holes are drilled, install a 28mm diameter galvanized steel pipe and a pressure relief valve to divert groundwater to the drainage ditch. After the water pressure stabilizes and the ballast no longer changes, stop drilling holes to drain water after one week of observation. (2) Anchor hole construction: After the hydraulic pressure release is completed and the roadbed is stable, the anchor hole construction begins. A 150mm diameter drilling rig is used to drill the hole. The drilling depth of the anchor hole is 5m. After the drilling is completed, the anchor rod is slowly inserted into the hole. (3) Anchor grouting: After the anchor is installed, grouting is carried out. The grouting pressure is controlled at 0.5-2.5Mpa. The grouting material is a high-flow ultra-early strength underwater anti-dispersion grouting material. The grouting method is the bottom grouting method. The anchor grouting should be carried out under the condition that the drainage hole is unobstructed; (4) Anchor bolt locking: clean the anchor end plate and install it on the anchor bolt and anchor it with a nut; (5) Grouting of drainage holes: CGM-340 ultrafine cement grouting is performed on the drainage holes with a grouting pressure of 0.3-0.4 MPa. After the grouting is completed, the drainage holes are sealed.

2. The method for treating the uplift of the roadbed of an operating subway underground excavation station according to claim 1 is characterized by: The 4-hour compressive strength of the high-fluidity, ultra-early-strength underwater anti-dispersion grouting material is 40Mpa, and the 28-day compressive strength is 65Mpa.

3. The method for treating the uplift of the roadbed of an operating subway underground excavation station according to claim 2 is characterized by: The positions of the threaded steel bars for prestressed concrete corresponding to the stratum gap water are all provided with water-stopping rings that expand when exposed to water.

4. The method for treating the uplift of the roadbed of an operating subway underground excavation station according to claim 1 is characterized by: The spacing of the anchor holes arranged longitudinally along the ballast bed is 5m.

5. The method for treating the uplift of the roadbed of an operating subway underground excavation station according to claim 1, 2, 3 or 4, characterized in that: When grouting the drainage hole, continue grouting after the drainage hole is blocked until slurry overflows from the next drainage hole, and the grouting of the hole is completed.

6. The method for treating the uplift of the roadbed of an operating subway underground excavation station according to claim 5 is characterized by: The outer part of the prestressed concrete threaded steel bar is provided with an anti-corrosion coating, which is epoxy resin and has a thickness of ≥300um.

7. The method for treating the uplift of the roadbed of an operating subway underground excavation station according to claim 5 is characterized by: The thickness of the water-stopping water-stopping ring that expands when exposed to water is 20 mm, and the maximum expansion rate is 250%-550%.

8. The method for treating the uplift of the roadbed of an operating subway underground excavation station according to claim 5 is characterized by: The diameter of the conical centering carrier is 110 mm and the height is 120 mm; the conical centering carrier is made of PE insulating material.

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