CN115573725A - Stratum reinforcing method for comprehensive pipe gallery tunnel to penetrate existing subway shield - Google Patents

Abstract

The invention discloses a stratum reinforcing method for a comprehensive pipe gallery tunnel to pass through an existing subway shield, which relates to the field of tunnel construction and comprises the steps of strengthening the bearing and anti-permeability capacity of a soil body by ground grouting reinforcement, reducing the deformation and seepage influence of the existing subway by pre-reinforcement in a subway tunnel, improving the self-stability of the front soil body and reducing the water permeability of the soil body by shield advanced grouting, controlling the deformation and water plugging of surrounding rocks by grouting reinforcement in the pipe gallery tunnel, and forming a complete prevention and control system by the connection of the four steps. Compared with the traditional grouting filling, the invention has more comprehensive safety prevention and control capability. In addition, the grouting range is optimized according to the stress characteristics of the existing subway with different sections, the large deformation and torsion risks of the existing shield interval are effectively prevented and controlled, the defect of time-consuming consumable materials of large-range whole reinforcement is avoided, and the construction benefit is greatly improved.

Description

A Ground Reinforcement Method for a Comprehensive Pipe Gallery Tunnel Passing Under an Existing Subway Shield

technical field

The invention relates to the field of tunnel construction, in particular to a ground reinforcement method for a comprehensive pipe gallery tunnel passing under an existing subway shield.

Background technique

At present, urban underground engineering construction is developing rapidly, and it is particularly important to plan and use underground space reasonably. The comprehensive pipe gallery integrates various engineering pipelines such as electric power, communication, gas, heating, water supply and drainage, and realizes unified planning, unified design, unified construction and management. However, with the development of subway construction in major cities, the construction of large-section comprehensive pipe corridor tunnels in urban areas often passes through various existing subway shield sections. The stratum disturbance caused by the excavation of the newly-built comprehensive utility gallery tunnel has brought huge safety hazards to the section close to the shield. When the shield excavation leads to stratum loss and stress disturbance, and indirectly induces the displacement of the upper existing subway structure beyond a certain range, it will cause serious damage to the new and existing tunnel structures, and even the surrounding stratum environment. In the slightest, the lining structure cracks, uneven settlement and inclination, and in severe cases, the ground subsides and the structure collapses, threatening the safety of people's lives and properties.

It is very important to actively prevent and control the safety impact of the construction of the new comprehensive utility gallery tunnel on the existing shield section above. Most of the existing measures only consider a single form of reinforcement, which cannot effectively control the safety of underground shield construction and the safety of structures close to the subway. In addition, the existing reinforcement system does not consider the special form of the overlapping section of the tunnel, and most of them are cross-crossing conditions. Furthermore, for the sake of safety, most of them are reinforced by large-scale grouting, which leads to low economic benefits of the project. Therefore, the development of a large-scale reinforcement that can effectively prevent and control the large deformation and torsional risk of settlement in the existing shield section and reduce unnecessary large-scale reinforcement has certain engineering significance for the safety prevention and economic benefit of the subsequent construction of the shield tunnel.

Contents of the invention

The purpose of the present invention is to solve the shortcomings in the above-mentioned technologies, and to provide a ground reinforcement method in which the comprehensive utility tunnel passes through the existing subway shield tunnel, and the reinforcement method can effectively prevent and control the large deformation and torsion of the existing shield section risk and avoid the diseconomy of large-scale reinforcement.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A ground reinforcement method for a comprehensive utility gallery tunnel passing under an existing subway shield, comprising:

Ground grouting reinforcement measures, through the ground grouting hole to inject double liquid grout into the ground to form a multi-faceted reinforcement wall, to achieve the strengthening of soil bearing and anti-seepage capacity;

The pre-reinforcement measures in the subway tunnel are to form the bottom reinforcement area by grouting the grouting pipe in the subway tunnel to the ground to reduce the deformation and seepage effects of the existing subway;

The advanced grouting measures for the shield body of the newly-built comprehensive pipe gallery are grouted to the soil above the front of the shield through the advanced grouting holes of the shield body, so as to achieve the self-stabilization of the soil in front of the shield and reduce the water permeability of the soil;

The grouting in the newly-built pipe gallery is reinforced, and the vault reinforcement area is formed by grouting the grouting pipe in the pipe gallery to the formation, so as to control the deformation of the surrounding rock and block water;

The ground grouting reinforcement, the subway tunnel pre-reinforcement, the shield body advance grouting, and the tunnel tunnel grouting reinforcement are complementary to each other, and they are connected together to form a complete reinforcement prevention and control system.

Further, the ground grouting holes are arranged at positions 2m and 5m from the centerline of the existing subway tunnel, and are drilled vertically on the ground. The drilling depth is within the range of 3m from the top and bottom of the tunnel structure to the surface, and the distance between the grouting holes is 3m. Arranged in plum blossom shape.

Further, the ground grouting holes include far-side ground grouting holes and near-side ground grouting holes; after the grouting holes are drilled, medium-coarse sand is pre-filled in the holes before the pipe gallery section is passed down.

Further, in the ground grouting reinforcement measures, when the existing subway line is deformed by more than 4mm during the down-passing process of the pipe gallery section, the WSS drilling and injection machine is used to carry out retreat grouting reinforcement, which is used to repair the soil on the surface and under the subway tunnel. For reinforcement.

Further, the ground grouting reinforcement measures include three types of reinforcement: outer crossing, overlapping crossing, and inner crossing, which avoids the uneconomical effect of large-scale reinforcement.

Further, the ground grouting holes adopt a hole arrangement scheme parallel to the extension direction of the comprehensive pipe gallery in the far section, and adopt a hole arrangement plan parallel to the extension direction of the tunnel in the near section where overlapping sections exist in the near section.

Further, for the pre-reinforcement in the subway tunnel, in order to avoid the horizontal displacement of the tunnel caused by grouting reinforcement, each ring of grouting is synchronously and symmetrically carried out at the 5 o'clock and 7 o'clock positions.

Further, the advance grouting of the shield is designed with a diameter of Φ50 drilling, a drilling depth of 18-20m, and an extrapolation angle of 13°. During the construction work, the length from the advanced grouting hole to the cutter head is about 6m reserved by Zhongshi, the actual effective grouting depth is about 14m, and the segment ring width is 1.5m, which is 8.7 rings. Bite, and do a cycle every 6 rings.

Further, the grouting in the newly-built pipe corridor is reinforced, and the cement-sodium silicate double-layer cement-sodium silicate is radially injected into the hand hole of the segment at 1 or 2 points near the end of the subway tunnel in the outer crossing section by laying steel flower pipes. Slurry: Grout vertically upward at 1 or 2 points and 10 or 11 points of the pipe gallery tunnel in the overlapping crossing section. Radial grouting at 1 point or 2 points and 10 points or 11 points of the pipe gallery tunnel is carried out in the inner crossing section.

The beneficial effects of the present invention are:

(1) The present invention comprehensively considers a complete prevention and control system that combines ground grouting reinforcement, subway tunnel pre-reinforcement, shield body advance grouting, and pipe gallery grouting reinforcement. Compared with traditional grouting schemes, it has more advantages. Strong security prevention and control capabilities;

(2) Based on the stress characteristics of different situations of subway tunnels passing under the newly-built pipe gallery, the present invention designs grouting schemes respectively to effectively prevent and control the risk of large deformation and torsion in the existing shield section, and avoids the time-consuming time-consuming reinforcement of a large area The shortcomings of consumables have greatly improved the construction efficiency.

Description of drawings

Fig. 1 is a layout plan view of the grouting holes on the ground near the tunnel strata of the present invention;

Fig. 2 is a positional relationship diagram of the grouting holes on the ground near the tunnel strata of the present invention;

Fig. 3 is a schematic diagram of the stratum reinforcement system of the outer crossing section of section A of the present invention;

Fig. 4 is a schematic diagram of the stratum reinforcement system of the B-section overlap crossing section of the present invention;

Fig. 5 is a schematic diagram of the stratum reinforcement system of the inner crossing section of the C section of the present invention;

Fig. 6 is a schematic diagram of advanced grouting reinforcement of the shield body of the new pipe gallery tunnel of the present invention;

In the figure: 1- the existing subway section on the far side, 2- the existing subway section on the near side, 3- the newly built comprehensive pipe gallery, 4- the far side ground grouting hole, 5- the near side ground grouting hole, 6- shield tunneling Machine, 7-grouting pipe in the subway cave, 8-grouting pipe in the tunnel gallery, 9-advance grouting hole in the shield body, 10-advance grouting range.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

As shown in Figure 1-6, a ground reinforcement method for a comprehensive utility gallery tunnel passing under an existing subway shield, including:

Ground grouting reinforcement measures, which are to inject double liquid grout into the formation through the far side ground grouting hole 4 and the near side ground grouting hole 5 to form a multi-faceted reinforcement wall, so as to achieve the strengthening of soil bearing and anti-seepage capacity;

The pre-reinforcement measures in the subway tunnel are to form the bottom reinforcement area by grouting the grouting pipe 7 in the subway tunnel to the ground to reduce the deformation and seepage effects of the existing subway;

The advanced grouting measures for the shield body of the newly-built comprehensive pipe gallery 3 are grouting to the soil above the shield machine 6 through the shield body advanced grouting hole 9, so as to achieve the self-stabilization of the soil in front of the shield machine 6 and reduce the soil permeability sex;

The grouting reinforcement in the 3rd hole of the newly-built comprehensive pipe gallery is to form the vault reinforcement area by grouting the grouting pipe 8 in the pipe gallery hole to the ground, so as to control the deformation of the surrounding rock and block water;

The ground grouting reinforcement, the subway tunnel pre-reinforcement, the shield body advance grouting, and the tunnel tunnel grouting reinforcement are complementary and jointly connected to form a complete prevention and control reinforcement system.

During construction, the specific construction steps are:

Step 1: When the shield machine 6 of the newly-built comprehensive pipe gallery 3 is about to pass through, vertical drilling shall be carried out at positions 2m and 5m outside the center line of the existing subway tunnel in advance, and the grouting hole spacing shall be 3m, arranged in a plum blossom shape. In the existing subway section 1 on the far side, the hole layout scheme parallel to the extension direction of the newly-built comprehensive pipe gallery 3 is adopted, and in the overlapping section of the existing subway section 2 on the near side, the hole layout plan parallel to the extension direction of the tunnel in the existing subway section 2 on the near side is adopted. Program. The drilling depth is within 3m above and below the existing tunnel structure to the surface. After the grouting holes are drilled, the holes are pre-filled with medium-coarse sand before the new integrated pipe gallery 3 is drilled down.

Step 2: During the underpassing process of the newly built comprehensive pipe gallery 3, the deformation of the existing subway line exceeds 4mm, and the WSS integrated drilling and injection machine is used for retreat grouting reinforcement, which is used to reinforce the surface and the soil below the subway tunnel. Surface grouting adopts cement-sodium silicate double slurry, P O42.5 ordinary portland cement single slurry, water-cement ratio 1:1, water glass (baume degree 39) and water by volume ratio 1:1 Dilution, cement slurry-diluted water glass volume ratio is 1:1, using on-site trial preparation, the initial setting time of the slurry is 60s, and the grouting pressure is controlled at 0.5-1MPa. It is worth noting that: when crossing on the outside, grouting is only performed on the two outer rows of the existing subway section 2 on the near side; When crossing, grouting is performed on the inner and outer sides of the existing subway section 2 on the near side and the inner side of the existing subway section 1 on the far side.

Step 3: In the existing subway section 2 on the near side, use the grouting pipe 7 in the subway hole reserved on the segment to perform grouting reinforcement on the wall of the adjacent existing subway section 2 segment, and use two grouting machines to separate the wall at the same time. The 5 o'clock and 7 o'clock positions of the same ring segment are reinforced by grouting, and the jump ring grouting method is adopted according to the principle of segment staggered assembly. The specific grouting reinforcement process is divided into two steps. The first step is pre-grouting, and pre-grouting reinforcement is performed at the 5 o'clock and 7 o'clock positions every three rings. The second step is tracking grouting. In order to avoid the pre-grouting from blocking the tracking grouting steel flower pipe, after the pre-grouting reinforcement is completed, start at the 5 o'clock and 7 o'clock positions of the middle ring reserved for the first step grouting position. Drill holes and pre-embed 4m long steel flower pipes, followed by tracking grouting with shield machine 6 tunneling and automatic monitoring data. In order to avoid the horizontal displacement of the existing tunnel caused by grouting reinforcement, the grouting of each ring is carried out synchronously for the 5 o'clock and 7 o'clock positions. Among them, the pre-buried grouting pipe 7 in the subway cave adopts a steel flower pipe with a diameter of Φ25mm, and the embedded depth of the steel flower pipe is 4 meters. The grouting pressure is 0.4-0.5MPa. The grout adopts cement-sodium silicate double-fluid grout, and each grouting section should be grouted repeatedly 2-3 times to ensure the quality of grouting.

Step 4: Considering the risk of collapse in the subsequent construction when excavating the upper soft and lower hard strata or weak strata, use the advanced grouting hole 9 on the upper shield body of the shield machine 6 to carry out grouting on the soil in the range of 2 to 12m above the front and upper part of the shield machine 6 cutterhead. Grouting reinforcement, the grouting grout adopts double liquid grouting, and the grouting principle is dual control of grouting pressure and grouting volume. The main purpose is to compact the soil above the cutter head in the shield construction area to ensure a certain degree of self-stability of the soil. At the same time, reduce the water permeability of the soil as much as possible and improve the overall stability of the soil above the cutter head of the shield machine 6. Among them, the construction drilling adopts drill bit: Φ50, drill pipe: Φ42*2m, drilling depth: 18-20m, extrapolation angle: 13°. The effective drilling depth is 20m in the construction operation, and 20m is taken as an example in the implementation. Among them, the length from the advanced grouting hole 9 reserved in the shield body to the cutter head is about 6m, the actual effective grouting depth is about 14m, and the segment is still wide 1.5m, that is, 8.7 rings, in order to ensure the occlusion of the two grouting surfaces before and after, a cycle is made every time 6 rings are advanced. In addition, the ratio of grout and phosphoric acid used in advance grouting is: water glass: water = 1:2, phosphoric acid: water = 1:30, dry cement: water = 10 (bag): 1m3, water glass: cement (mixed) =1:1, water glass: phosphoric acid (mixed) =1:1. The ratio of the slurry can be adjusted according to the actual situation on site. The initial setting time of the slurry can be controlled at about 50s at the beginning of injection. The slurry pressure is controlled within 1MPa, and the initial setting time of phosphoric acid is controlled between 25s-30s.

Step 5: Strengthen the secondary grouting inside the tunnel of the newly-built comprehensive pipe gallery 3, and at the same time drill the grouting pipe 8 in the tunnel vault to reinforce the soil at the bottom of the subway tunnel. In the outer crossing section of the A or A' section, as shown in Figure 3, within the range where the newly built comprehensive pipe corridor 3 tunnel passes through the existing subway section 2 on the near side, it should be closer to the existing subway section 2 on the near side. The 1-point or 2-point segment hand hole at one end is injected with cement-sodium silicate double liquid slurry by drilling a steel flower tube. In the overlap crossing section of B or B' section, as shown in Figure 4, the newly-built comprehensive utility corridor 3 tunnel completely overlaps with the plane of the existing subway section 2 on the near side. Point or 11 o'clock segment segment hand hole is drilled vertically upwards to set up a steel flower tube to inject cement-sodium silicate double liquid slurry. In the inner crossing section of the C section, as shown in Figure 5, the newly-built integrated utility corridor 3 tunnel is located between the far side and the near side of the existing subway section 2, and within the scope of this section, points 1 or 2 and point 10 of the utility corridor tunnel are adopted. Or the hand hole of the 11 o'clock segment is radially injected with cement-sodium silicate double slurry by drilling a steel flower tube. According to the principle of staggered assembly of segments, the grouting reinforcement adopts the method of jump ring drilling and grouting, and the constructed segments are reinforced by grouting 30m before the tunnel of the newly built comprehensive pipe gallery 3. If the piece comes out of the tail of the shield, follow up the grouting reinforcement measures in time.

The ground grouting reinforcement, the pre-reinforcement in the subway tunnel, the advance grouting of the shield body and the grouting reinforcement in the tunnel of the tunnel in the embodiment of the reinforcement method can be appropriately adjusted according to the construction deformation monitoring situation. When the formation deformation is less than 60% of the standard warning value, the combination of advanced grouting of the shield body + pre-reinforcement in the subway tunnel hole is adopted; when the formation deformation is 60%-80% of the standard warning value, the advanced grouting of the shield body + subway tunnel hole is used Internal pre-reinforcement + ground grouting reinforcement combination; when the formation deformation is greater than the standard warning value, the shield body advance grouting + subway tunnel pre-reinforcement + ground grouting reinforcement + grouting reinforcement combination in the tunnel tunnel is adopted.

From the perspective of construction as a whole, this reinforcement method comprehensively considers a complete prevention and control system that combines ground grouting reinforcement, subway tunnel pre-reinforcement, shield body advance grouting, and pipe tunnel grouting reinforcement. The grouting scheme has stronger safety prevention and control capabilities; moreover, this reinforcement method is based on the stress characteristics of different situations of the subway tunnel under the new pipe gallery, and the grouting scheme is designed respectively to effectively prevent and control the large deformation and torsion risk of the existing shield section , and avoid the time-consuming and consumable shortcomings of large-scale reinforcement, which greatly improves the construction efficiency.

The present invention has been described in detail above with reference to the accompanying drawings and embodiments, and those skilled in the art can make various changes to the present invention according to the above description. Therefore, some details in the embodiments should not be construed as limiting the present invention, and the present invention will take the scope defined by the appended claims as the protection scope of the present invention.

Claims (8)

1. A stratum reinforcing method for a comprehensive pipe gallery tunnel to pass through an existing subway shield is characterized by comprising the following steps:

ground grouting reinforcement measures are adopted, and double-liquid slurry is injected into the stratum through a far-side ground grouting hole (4) and a near-side ground grouting hole (5) to form a multi-surface reinforced wall;

pre-reinforcing in the subway tunnel, and forming a bottom reinforcing area by grouting the stratum through a grouting pipe (7) in the subway tunnel;

establishing a shield advanced grouting measure of the comprehensive pipe gallery, and grouting soil body above the front of the shield through a shield advanced grouting hole (9);

grouting and reinforcing in the newly-built pipe gallery hole, and grouting the stratum through a grouting pipe (8) in the pipe gallery hole to form a vault reinforcing area;

the ground grouting reinforcement, the pre-reinforcement in the subway tunnel, the shield body advanced grouting and the pipe gallery grouting reinforcement are complementary and are connected together to form a complete prevention and control reinforcement system.

2. The method for reinforcing the stratum of the underground existing subway shield penetrating through the comprehensive pipe gallery tunnel according to claim 1, wherein the far-side ground grouting holes (4) and the near-side ground grouting holes (5) are vertically drilled from the ground to the stratum at positions 2m and 5m outside the center line of the existing subway tunnel, the drilling depth ranges from the upper part to the lower part of the tunnel structure to the ground surface, the distance between the grouting holes is 3m, and the grouting holes are arranged in a quincunx shape.

3. The stratum reinforcing method for the underground tunnel penetrating existing subway shield of the comprehensive pipe gallery according to claim 1, wherein ground grouting reinforcement measures are adopted, and when the deformation of the existing subway line exceeds 4mm in the process of penetrating the newly-built comprehensive pipe gallery (3), backward grouting reinforcement is carried out by adopting a WSS drilling and grouting integrated machine.

4. The method for reinforcing the stratum of the underground through existing subway shield of the comprehensive pipe gallery tunnel according to claim 1, wherein the ground grouting reinforcement measures comprise an outside crossing reinforcement type, an overlapping crossing reinforcement type and an inside crossing reinforcement type.

5. The method for reinforcing the stratum of the underground tunnel penetrating the existing subway shield of the utility tunnel according to claim 1, wherein the ground grouting holes are distributed in a manner parallel to the extending direction of the newly-built utility tunnel (3) in the far-side existing subway section (1) and in a manner parallel to the extending direction of the tunnel in the near-side existing subway section (2).

6. The method for reinforcing the stratum of the existing underground tunnel shield penetrating through the comprehensive pipe gallery tunnel according to claim 1, wherein the underground tunnel is pre-reinforced, and in order to avoid horizontal tunnel displacement caused by grouting reinforcement, each ring of grouting is synchronously and symmetrically performed aiming at 5-point location and 7-point location.

7. The method for reinforcing the stratum of the underground existing subway shield penetrating through the comprehensive pipe gallery tunnel according to claim 1, wherein the shield body is subjected to advanced grouting by adopting a phi 50 drilling diameter, a drilling depth of 18-20m and an external inserting angle of 13 degrees; in the construction operation, the length from the advanced grouting hole (9) of the shield body to the cutter head of the middle shield is about 6m, the actual effective grouting depth is about 14m, the ring width of the duct piece is 1.5m, namely 8.7 rings, and in order to ensure the occlusion of the grouting surfaces of the front and the back twice, circulation is performed once when 6 rings are pushed.

8. The method for reinforcing the stratum of the existing subway shield penetrating under the comprehensive pipe gallery tunnel according to claim 1, characterized in that grouting reinforcement is performed in a hole of the newly-built comprehensive pipe gallery (3), and cement-water glass double-liquid slurry is radially injected in an outer penetrating section by adopting a mode of drilling a grouting pipe (8) in the hole of the pipe gallery at a 1 point or 2 point of a pipe segment of the newly-built comprehensive pipe gallery (3) at the end close to the subway tunnel; grouting vertically upwards at 1 point or 2 points and 10 points or 11 points of a tunnel of a newly-built comprehensive pipe gallery (3) at the overlapping crossing section; radial grouting is adopted at 1 point or 2 point and 10 points or 11 points of the tunnel of the newly-built comprehensive pipe gallery (3) at the inner side crossing section.

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