Shield construction method for water-rich soft soil stratum

Abstract

The invention discloses a shield construction method for a water-rich soft soil stratum, and belongs to the technical field of shield construction. The shield construction method comprises the steps that according to the position of a building, a foundation of the building and a water-rich soft soil layer below the foundation are reinforced through sleeve valve pipe pre-grouting on the earth surface; shield tunneling is conducted on the water-rich soft soil stratum, a plurality of outer side ribbed pipe pieces are laid in the shield tunneling process, grouting is conducted on the stratum behind the outer side ribbed pipe pieces synchronously, and the multiple outer side ribbed pipe pieces support the pile foundation obtained after abrasion cutting; the grouting holes are grouted through the frame tracking grouting platform, so that the soil layer on the outer side of the outer ribbed pipe piece forms a grouting reinforcement layer; and settlement deformation of the building before and after shielding is monitored, and when the settlement deformation of the building after shielding exceeds a threshold value, the building is reinforced. According to the shield construction method for the water-rich soft soil stratum, settlement deformation of a building can be effectively reduced, and the anti-seismic safety and the follow-up service life of a building structure are guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of shield construction, and in particular relates to a shield construction method for water-rich soft soil strata. Background Art

[0002] With the development of urban underground space development technology, shield construction has been widely promoted and applied due to its high degree of mechanization, small impact on the ground environment, safety and efficiency. During the shield construction process, affected by geological conditions, tunnel direction and other factors, the initial stage often faces difficulties such as surface uplift and collapse, water and sand gushing from the tunnel entrance, especially in water-rich soft soil layers.

[0003] At present, when the shallowly buried rail transit shield tunnel in the water-rich soft soil layer passes under the pile foundation of multi-layer brick-concrete masonry structure or concrete buildings, the basic method adopted is to demolish and pull out the piles before the shield tunnel passes through. However, with the increasing cost of demolition and the tight schedule for the opening and operation of the subway, coordination is extremely difficult. New buildings need to be built on other plots of land, which has a high cost and directly affects the time node and construction cost of the shield line penetration plan. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a shield construction method for water-rich soft soil strata, the purpose of which is to effectively reduce the settlement and deformation of buildings, ensure the seismic safety of the building structure and subsequent service life, and avoid the problems of demolition and pile extraction that affect the construction period and construction cost of the shield line penetration plan.

[0005] To achieve the above object, the present invention provides a shield construction method for water-rich soft soil strata, the shield construction method comprising:

[0006] According to the location of the building, the foundation of the building and the water-rich soft soil layer below are reinforced through pre-grouting of sleeve valve pipes on the surface, and multiple pile foundations of the building are inserted in the water-rich soft soil layer;

[0007] Shield tunneling is performed on the water-rich soft soil layer, and multiple outer ribbed segments are laid during the shield tunneling process, and grouting is simultaneously performed on the stratum behind the outer ribbed segments, wherein the multiple outer ribbed segments support the pile foundation after grinding and cutting, and each of the outer ribbed segments has multiple grouting holes arranged at intervals;

[0008] The grouting holes are grouted by tracking the grouting platform through a vehicle frame, so that the soil layer outside the outer ribbed segment forms a grouting reinforcement layer;

[0009] Monitor the settlement deformation of the building before and after the shield tunnel. When the settlement deformation of the building behind the shield tunnel exceeds the threshold, reinforce the building.

[0010] Optionally, the reinforcing the building includes:

[0011] Strengthen the building foundation through sleeve valve pipe grouting on the surface;

[0012] Enlarging the building foundation area by means of a concrete foundation slab on the building foundation;

[0013] Carry out earthquake-resistant reinforcement construction on the upper building structure of the building.

[0014] Optionally, the seismic reinforcement construction includes:

[0015] The upper building structure of the building is provided with a ring beam, a structural column, an outer steel section or a steel mesh mortar surface layer on both sides of the wall, and a fiber composite material is pasted.

[0016] Optionally, the shield tunneling of the water-rich soft soil stratum includes: adding a full-ring roller cutter to the cutterhead of the shield machine.

[0017] Optionally, shield tunneling in the water-rich soft soil stratum further comprises:

[0018] Strengthen the control of the tunneling parameters of the shield machine, which include soil bin pressure, cutter head speed and torque, shield thrust and propulsion speed, grouting pressure and grouting volume, and excavation volume.

[0019] Optionally, the monitoring of the settlement deformation of the building before and after the shield tunneling, and reinforcing the building when the settlement deformation of the building after the shield tunneling exceeds a threshold, includes:

[0020] Monitoring the settlement deformation before and after the shield of the building, when the settlement deformation behind the shield of the building exceeds a first threshold, grouting each of the grouting holes again by tracking the grouting platform through the frame;

[0021] When the settlement deformation of the building after the shield tunnel exceeds the second threshold, the building is reinforced;

[0022] The second threshold is greater than the first threshold.

[0023] Optionally, the first threshold a satisfies: 10<a≤15mm, and the second threshold b satisfies: 15<b<30mm.

[0024] Optionally, the outer ribbed segment includes a segment body and a raised portion, wherein the raised portion is located on the outer side of the segment body, the raised portion is a conical structure, and the cross-sectional area of ​​the raised portion gradually increases in the direction toward the segment body, and the grouting hole passes through the segment body and the raised portion.

[0025] Optionally, the thickness of the raised portion is 100-200 mm, the diameter of the first surface of the raised portion is 500-600 mm, and the diameter of the second surface of the raised portion is 700-800 mm.

[0026] Optionally, the grouting uses a double slurry formed by cement slurry and water glass.

[0027] The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0028] In general, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:

[0029] For a shield construction method for a water-rich soft soil layer provided in an embodiment of the present invention, when shielding a water-rich soft soil layer below a building, first, according to the location of the building, the foundation of the building and the water-rich soft soil layer below are reinforced by pre-grouting through a sleeve valve pipe on the surface, and multiple pile foundations of the building are inserted into the water-rich soft soil layer, thereby reinforcing the structural strength of the foundation and the water-rich soft soil layer below the building in advance, and reducing the settlement deformation of the building during the subsequent shield process. Then, shielding is performed on the water-rich soft soil layer, and multiple outer ribbed segments are laid during the shield process, and grouting is performed in the stratum behind the outer ribbed segments simultaneously, and multiple outer ribbed segments support the pile foundation after grinding and cutting, and each outer ribbed segment has a plurality of grouting holes arranged at intervals. The convex portion of the outer ribbed segment at the later stage of laying can increase the roughness of the outer side of the segment, thereby increasing the bonding strength between the segment and the outer soil layer, and the bonding strength between the segment and the pile foundation after grinding and cutting by the shield machine. Finally, the grouting holes are grouted by tracking the grouting platform with a frame, so that the soil layer outside the outer ribbed segment forms a grouting reinforcement layer, thereby increasing the strength of the soil layer outside the segment to further increase the bonding strength between the segment and the outer soil layer, and between the segment and the pile foundation after the shield machine is cut, ensuring the structural strength of the stratum below the building, thereby reducing the settlement and deformation of the building, ensuring the seismic safety of the building structure and the subsequent service life, and avoiding the problem of affecting the construction period and construction cost of the shield line penetration plan due to demolition and pile extraction. In addition, during the construction process, the settlement and deformation of the building before and after the shield is monitored. When the settlement and deformation of the building after the shield exceeds the threshold, the building is reinforced to ensure the structural strength of the building itself, thereby further reducing the settlement and deformation of the subsequent building, so that the impact on the building structure is within a controllable range.

[0030] That is to say, the shield construction method for water-rich soft soil strata provided by the embodiment of the present invention can effectively reduce the settlement and deformation of buildings, ensure the seismic safety of the building structure and its subsequent service life, and avoid the problems of demolition and pile extraction that affect the construction period time nodes and construction costs of the shield line penetration plan. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a flow chart of a shield construction method for water-rich soft soil strata provided by an embodiment of the present invention;

[0032] Figure 2 It is a schematic diagram of shield construction provided by an embodiment of the present invention;

[0033] Figure 3 It is a schematic diagram of assembling the outer ribbed tube segment provided in an embodiment of the present invention.

[0034] In all the drawings, the same reference numerals represent the same technical features, specifically:

[0035] 1. Outer ribbed segment; 11. Segment body; 12. Raised part; 2. Grouting hole; 3. Grouting reinforcement layer; 4. Steel flower pipe; 100. Pile foundation; 200. Foundation; 300. Superstructure. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0039] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0041] Example:

[0042] Figure 1 Flow chart of a shield construction method for water-rich soft soil strata provided by an embodiment of the present invention. Figure 1 As shown, the shield construction method includes:

[0043] S1. According to the location of the building, the building foundation 200 and the water-rich soft soil layer below are reinforced by pre-grouting on the ground surface through sleeve valve pipes.

[0044] Wherein, a plurality of pile foundations 100 of the building are inserted into the water-rich soft soil layer.

[0045] S2. Shield tunneling is performed on the water-rich soft soil stratum. During the shield tunneling process, a plurality of outer ribbed segments 1 are laid, and grouting is simultaneously performed in the stratum behind the outer ribbed segments 1. The plurality of outer ribbed segments 1 support the pile foundation 100 after grinding and cutting.

[0046] Each outer ribbed segment 1 has a plurality of grouting holes 2 arranged at intervals (see Figure 2 ).

[0047] S3, grouting each grouting hole 2 by tracking the grouting platform through the frame, so that the soil layer outside the outer ribbed segment 1 forms a grouting reinforcement layer 3.

[0048] S4. Monitor the settlement deformation of the building before and after the shield tunnel. When the settlement deformation of the building behind the shield tunnel exceeds the threshold, reinforce the building.

[0049] With regard to a shield construction method for a water-rich soft soil layer provided in an embodiment of the present invention, when performing shield construction on a water-rich soft soil layer below a building, first, according to the location of the building, pre-grouting is performed on the surface through sleeve valve pipes to reinforce the foundation 200 of the building and the water-rich soft soil layer below, and a plurality of pile foundations 100 of the building are inserted into the water-rich soft soil layer, thereby reinforcing the structural strength of the foundation 200 and the water-rich soft soil layer below the building in advance, thereby reducing the settlement and deformation of the building during the subsequent shield construction process. Then, a shield tunnel is carried out on the water-rich soft soil stratum. During the shield tunneling process, multiple outer ribbed segments 1 are laid, and grouting is simultaneously performed in the stratum behind the outer ribbed segments 1. The multiple outer ribbed segments 1 support the pile foundation 100 after grinding and cutting. Each outer ribbed segment 1 has a plurality of grouting holes 2 arranged at intervals. The raised portion 12 (i.e., the ribbed structure) on the outer side of the outer ribbed segment 1 in the later stage of laying can increase the roughness of the outer side of the segment, thereby increasing the bonding strength between the segment and the outer soil layer, as well as the bonding strength between the segment and the pile foundation 100 after grinding and cutting by the shield machine. Finally, the frame tracks the grouting platform to grout each grouting hole 2, so that the soil layer outside the outer ribbed segment 1 forms a grouting reinforcement layer 3, thereby increasing the strength of the soil layer outside the segment to further increase the bonding strength between the segment and the outer soil layer, and between the segment and the pile foundation 100 cut by the shield machine, thereby ensuring the structural strength of the stratum below the building, thereby reducing the settlement deformation of the building, ensuring the seismic safety of the building structure and the subsequent service life, and avoiding the problem of affecting the construction period and construction cost of the shield line penetration plan due to demolition and pile extraction. In addition, during the construction process, the settlement deformation of the building before and after the shield is monitored. When the settlement deformation of the building after the shield exceeds the threshold, the building is reinforced to ensure the structural strength of the building itself, thereby further reducing the settlement deformation of the subsequent building, so that the impact on the building structure is within a controllable range.

[0050] That is to say, the shield construction method for water-rich soft soil strata provided by the embodiment of the present invention can effectively reduce the settlement and deformation of buildings, ensure the seismic safety of the building structure and its subsequent service life, and avoid the problems of demolition and pile extraction that affect the construction period time nodes and construction costs of the shield line penetration plan.

[0051] In addition, the shield construction method provided by the present invention can not only effectively enhance the structural strength of the stratum below the building, but also effectively enhance the structural strength of the building itself (including the foundation 200 and the upper building structure 300) when necessary, reduce the settlement and deformation of the building during and after the shield, and ensure the seismic safety of the building structure and its subsequent service life.

[0052] It is easy to understand that after the pile foundation 100 is ground, one end of the pile foundation 100 facing the outer ribbed segment 1 can be clamped between the protrusions 12 of the two outer ribbed segments 1, or one part abuts against the segment body 11 and the other part abuts against the higher protrusion 12 (see FIG. Figure 2 ), the pile foundation 100 is not easy to move, reducing the risk of movement between the pile foundation 100 and the relatively outer ribbed segment 1, thereby increasing the supporting strength of the segment to the pile foundation 100 after grinding and cutting, and reducing the risk of settlement and deformation caused by the misalignment of the two.

[0053] In one implementation of the present invention, in step S2, shield tunneling is performed on the water-rich soft soil stratum, including: adding a full-ring roller cutter to the cutterhead of the shield machine.

[0054] It is easy to understand that adding a full-ring cutter to the shield machine is beneficial to grinding and cutting the concrete pile foundation 100 under the building, which not only ensures the construction progress but also avoids damage to the conventional cutter head during grinding and cutting.

[0055] Furthermore, in step S2, shield tunneling is performed on the water-rich soft soil layer, and further includes:

[0056] Strengthen the tunneling parameter control of the shield machine, including soil bin pressure, cutter head speed and torque, shield thrust and propulsion speed, grouting pressure and grouting volume, and excavation volume. By improving the tunneling parameter control, the construction efficiency can be improved during the shield pile foundation 100.

[0057] In this embodiment, step S4: monitoring the settlement deformation of the building before and after the shield, when the settlement deformation of the building after the shield exceeds a threshold, reinforcing the building, including:

[0058] Monitor the settlement deformation before and after the shield of the building. When the settlement deformation after the shield of the building exceeds a first threshold, grout each grouting hole 2 again by tracking the grouting platform through the frame;

[0059] When the settlement deformation of the building after the shield tunneling exceeds the second threshold, the building is reinforced, wherein the second threshold is greater than the first threshold.

[0060] In the above-mentioned embodiment, by monitoring the settlement deformation before and after the shield of the building, it can be determined whether to reinforce the structure of the building itself. When the settlement deformation of the building after the shield is small, it means that the impact of the shield on the building can be regarded as negligible and no processing is required. When the settlement deformation of the building after the shield exceeds the first threshold, the frame tracking grouting platform is used to grout each grouting hole 2 again. At this time, the impact of the shield on the building is small. By grouting each grouting hole 2 again, the strength of the grouting reinforcement layer 3 can be further strengthened, ensuring its support strength for the pipe segment and the pile foundation 100 after grinding and cutting, and reducing subsequent settlement deformation. When the settlement deformation of the building after the shield exceeds the second threshold, the shield has a greater impact on the building at this time, and it is necessary to directly reinforce the structure of the building itself to reduce subsequent settlement deformation, thereby ensuring the seismic safety of the building structure and subsequent service life.

[0061] Exemplarily, the first threshold a satisfies: 10<a≤15 mm, and the second threshold b satisfies: 15<b<30 mm.

[0062] In this embodiment, in step S4, reinforcing the building includes:

[0063] S401, reinforcing the building foundation 200 on the ground surface by sleeve valve pipe grouting.

[0064] S402, expanding the area of ​​the building foundation 200 by means of a concrete foundation slab on the building foundation 200.

[0065] S403, performing earthquake-resistant reinforcement construction on the upper building structure 300 of the building.

[0066] In the above embodiment, the building foundation 200 is reinforced by sleeve valve pipe grouting, which can further increase the structural strength of the building foundation 200. By expanding the foundation area of ​​the building by a concrete foundation slab on the building foundation 200, the supporting area of ​​the building foundation 200 can be increased, and the subsequent deformation and settlement of the building can be reduced.

[0067] Specifically, in step S403, the seismic reinforcement construction includes:

[0068] Ring beams, structural columns, external steel sections or steel mesh mortar surface layers on both sides of the wall are added to the upper building structure 300 of the building, and fiber composite materials are pasted.

[0069] In the above-mentioned implementation, the strength of the upper structure of the building can be enhanced by adding ring beams, structural columns, externally clad steel sections or double-sided steel mesh mortar surface layers on the walls, as well as gluing fiber composite materials for reinforcement, thereby ensuring the seismic safety and subsequent service life of the upper structure of the building.

[0070] Figure 3 FIG. 1 is a schematic diagram of assembling an outer ribbed tube segment provided by an embodiment of the present invention. Figure 3 As shown, the outer ribbed segment 1 includes a segment body 11 and a raised portion 12. The raised portion 12 is located outside the segment body 11. The raised portion 12 is a conical structure, and the cross-sectional area of ​​the raised portion 12 gradually increases in the direction toward the segment body 11. The grouting hole 2 passes through the segment body 11 and the raised portion 12.

[0071] In the above embodiment, the raised portion 12 is a conical structure, so that the inclined surfaces formed on both sides of the raised portion 12 can better abut against the ground pile foundation 100 in the tangential direction of the pipe segment.

[0072] Exemplarily, a steel flower pipe 4 is inserted into the grouting hole 2 , and the steel flower pipe 4 extends radially along the segment body 11 to achieve precise grouting of the grouting reinforcement layer 3 .

[0073] Exemplarily, the thickness of the raised portion 12 is 100-200 mm, the diameter of the first surface of the raised portion 12 is 500-600 mm, and the diameter of the second surface of the raised portion 12 is 700-800 mm.

[0074] It should be noted that grouting uses a double slurry formed by cement slurry and water glass. After the double slurry solidifies, it has high structural strength and strong adhesion.

[0075] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A shield construction method for water-rich soft soil strata, It is characterized in that The shield construction method comprises: According to the location of the building, the foundation (200) of the building and the water-rich soft soil layer below are reinforced by pre-grouting with sleeve valve pipes on the ground surface, and a plurality of pile foundations (100) of the building are inserted into the water-rich soft soil layer; Shield tunneling is performed on a water-rich soft soil layer, a plurality of outer ribbed segments (1) are laid during the shield tunneling process, and grouting is simultaneously performed on the strata behind the outer ribbed segments (1), the plurality of outer ribbed segments (1) support the pile foundation (100) after grinding and cutting, and each of the outer ribbed segments (1) has a plurality of grouting holes (2) arranged at intervals; Grouting is performed on each of the grouting holes (2) by tracking the grouting platform with a vehicle frame, so that a grouting reinforcement layer (3) is formed on the soil layer outside the outer ribbed segment (1); Monitor the settlement deformation of the building before and after the shield tunnel. When the settlement deformation of the building behind the shield tunnel exceeds the threshold, reinforce the building.

2. A shield construction method for water-rich soft soil strata according to claim 1, It is characterized in that The reinforcement of the building includes: Reinforcing the foundation (200) of the building by grouting with sleeve valve pipes on the ground surface; Expanding the building foundation (200) area by means of a concrete foundation slab on the building foundation (200); The upper building structure (300) of the building is subjected to earthquake-resistant reinforcement construction.

3. A shield construction method for water-rich soft soil strata according to claim 2, It is characterized in that The seismic reinforcement construction includes: The upper building structure (300) of the building is additionally provided with a ring beam, a structural column, an outer steel section or a steel mesh mortar surface layer hung on both sides of the wall, and a fiber composite material is pasted.

4. A shield construction method for water-rich soft soil strata according to claim 1, It is characterized in that The shield tunneling for the water-rich soft soil stratum comprises: adding a full-ring roller cutter to the cutter head of the shield machine.

5. A shield construction method for water-rich soft soil strata according to claim 4, It is characterized in that The shield tunneling in the water-rich soft soil stratum also includes: Strengthen the control of the tunneling parameters of the shield machine, which include soil bin pressure, cutter head speed and torque, shield thrust and propulsion speed, grouting pressure and grouting volume, and excavation volume.

6. A shield construction method for water-rich soft soil strata according to claim 1, It is characterized in that The monitoring of the settlement deformation before and after the shield of the building, when the settlement deformation after the shield of the building exceeds a threshold, the building is reinforced, including: Monitoring the settlement deformation before and after the shield of the building, and when the settlement deformation after the shield of the building exceeds a first threshold, grouting each of the grouting holes (2) again by tracking the grouting platform through the frame; When the settlement deformation of the building after the shield tunnel exceeds the second threshold, the building is reinforced; The second threshold is greater than the first threshold.

7. A shield construction method for water-rich soft soil strata according to claim 6, It is characterized in that The first threshold a satisfies: 10<a≤15mm, and the second threshold b satisfies: 15<b<30mm.

8. A shield construction method for water-rich soft soil strata according to any one of claims 1 to 7, It is characterized in that The outer ribbed segment (1) comprises a segment body (11) and a raised portion (12); the raised portion (12) is located outside the segment body (11); the raised portion (12) is a conical structure; and the cross-sectional area of ​​the raised portion (12) gradually increases in a direction toward the segment body (11); the grouting hole (2) passes through the segment body (11) and the raised portion (12).

9. A shield construction method for water-rich soft soil strata according to claim 8, It is characterized in that The thickness of the raised portion (12) is 100-200 mm, the diameter of the first surface of the raised portion (12) is 500-600 mm, and the diameter of the second surface of the raised portion (12) is 700-800 mm.

10. A shield construction method for water-rich soft soil strata according to any one of claims 1 to 7, It is characterized in that The grouting adopts double slurry formed by cement slurry and water glass.

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