Underground obstacle processing structure and construction method

Abstract

The invention belongs to the technical field of pile pulling construction of risk source protection, and discloses an underground obstacle processing structure and a construction method. In order to solve the problems in the prior art, before pile pulling, temporary steel pipe piles are driven for soil retaining and slope cutting and leveling of a site, the problem that pile foundation obstacles in the slope environment are difficult to remove can be effectively solved, and meanwhile the influence of pile pulling operation on existing underground municipal facilities is reduced; the MJS reinforcing body is adopted to reinforce the adjacent risk source, so that the influence of the soil unloading effect of pile pulling operation on deformation and settlement of the adjacent risk source can be reduced; before shield penetration, a pile foundation conflicting with a shield tunnel is pulled out by adopting a full-rotation pile pulling construction process, and pile hole backfilling is performed by adopting solid fluidized soil, so that the construction risk of shield pile grinding is reduced, and smooth shield construction is guaranteed. According to the underground obstacle treatment structure and the construction method, the construction method is simple, convenient, feasible, safe and reliable, and a good protection effect can be achieved on existing municipal facilities and adjacent risk sources.

Description

Technical Field

[0001] The present invention belongs to the technical field of pile extraction construction for risk source protection, and in particular relates to an underground obstacle treatment structure and a construction method. Background Art

[0002] With the vigorous development of rail transit projects in my country, the subway network is becoming more and more dense, and the route of the line will inevitably conflict with the underground structure of the existing municipal facilities, such as the enclosure structure of the municipal pipeline corridor, the pile foundation of the building or bridge, etc. At present, the construction of subway section tunnels is mainly based on the shield method. In order to solve the problem of conflict between the section and underground obstacles, especially for pile foundations with large number, large diameter, high strength and high steel content, the shield machine direct grinding solution will cause the following effects:

[0003] 1. The steel bars will be entangled on the cutterhead panel, causing the shield cutterhead to be stuck;

[0004] 2. The broken steel bars and piles enter the screw machine, causing the screw machine to get stuck or cause a risk of gushing;

[0005] 3. The cutterhead is prone to mud cakes. When grinding piles, concrete blocks accumulate in front of the cutterhead, which increases the thrust of the shield and makes it difficult to feed slag, increasing the risk of mud cakes on the cutterhead.

[0006] 4. The composite cutterhead equipped with a roller cutter is heavy, the shield machine is very easy to fall and difficult to raise its head, and the shield posture and axis control are difficult;

[0007] 5. Pile grinding operations near important risk sources take a long time, have a great impact on soil disturbance, and are not conducive to the control of deformation of risk sources.

[0008] Therefore, it is necessary to invent an underground obstacle handling structure and construction method. Before the shield tunnel passes through, the underground obstacles should be cleaned up and the removed pile holes should be backfilled to ensure the smooth implementation of the shield tunnel. At the same time, the surrounding important risk sources should be pre-reinforced to reduce the impact of the pile extraction operation on the surrounding environment. Summary of the invention

[0009] In order to overcome the above-mentioned shortcomings of the prior art, an object of the present invention is to provide an underground obstacle processing structure, aiming to solve the problems existing in the prior art.

[0010] The technical solution adopted by the present invention to solve the technical problem is:

[0011] An underground obstacle treatment structure, including slopes, underground structures, concrete force transmission belts, cap beams, retaining piles, shield tunnels, steel pipe piles, MJS reinforcement bodies, pile hole backfill and risk sources;

[0012] The underground structures, concrete force transmission belts, cap beams, retaining piles, shield tunnels, steel pipe piles, MJS reinforcement bodies, and pile hole backfill are arranged in the soil of the slope, and the risk source is located on one side of the soil of the slope;

[0013] The retaining piles are arranged around the underground structure, and the concrete force transmission belt is arranged between the retaining piles and the underground structure;

[0014] The shield tunnel is arranged below the retaining piles and underground structures, and the shield tunnel is arranged to conflict with the retaining piles;

[0015] The MJS reinforcement body is arranged between the risk source and the shield tunnel;

[0016] The steel pipe pile is arranged between the MJS reinforcement body and the retaining pile;

[0017] The pile hole backfill material is arranged around the retaining pile, and the cap beam is arranged on the top of the retaining pile.

[0018] Preferably, the underground structure is a pipe jacking shaft, an underground pipe gallery or an underground tunnel.

[0019] Preferably, the retaining piles are reinforced concrete structures, and the pile diameters of the retaining piles are 600 mm, 800 mm or 1000 mm.

[0020] Preferably, the shield tunnel comprises a plurality of lining units of reinforced concrete structure connected end to end in a circular shape, the concrete of the lining units is C50 concrete, and the bottom of the retaining piles corresponding to the position of the shield tunnel is located in the shield tunnel.

[0021] Preferably, the retaining piles arranged around the underground structure form a closed retaining body;

[0022] The steel pipe piles are made of Q235 steel. Several of the steel pipe piles are arranged along the extension direction of one side of the square enclosure and beyond the two ends of one side of the square enclosure. The top height of the steel pipe piles is higher than the top height of the square enclosure.

[0023] Preferably, the MJS reinforcement body is a high-pressure rotary jet pile, and a plurality of the high-pressure rotary jet piles are arranged along the extension direction of one side of the square enclosure.

[0024] The present invention also includes a construction method of an underground obstacle treatment structure, which is applied to the above-mentioned underground obstacle treatment structure and includes the following steps:

[0025] S1. Use the MJS reinforcement body to reinforce the soil between the risk source and the shield tunnel;

[0026] S2, driving the steel pipe piles outside the retaining piles for retaining support;

[0027] S3. Excavate the slope corresponding to the underground structure until the top beam is exposed and then remove the top beam to expose the pile position of the retaining pile, and then level the excavated site;

[0028] S4. Perform full-turn obstacle removal and pile pulling construction at the pile position of the retaining pile, and remove the pile body of the retaining pile;

[0029] S5. Carry out secondary grouting inside the tunnel within 1m outside the segment structure of the shield tunnel.

[0030] Preferably, in step S4, the steps of full-rotation obstacle removal and pile pulling construction are as follows:

[0031] S41, pressing the steel sleeve into place to a predetermined depth;

[0032] S42, punching and drilling holes by using a full-rotation drilling rig;

[0033] S43, twisting and breaking the retaining piles in sections;

[0034] S44. Go to the designed removal elevation and remove the broken retaining pile segment;

[0035] S45, backfilling the pile hole formed at the pile position of the retaining pile;

[0036] S46, remove the steel sleeve;

[0037] S47, repeat the above steps to pull out the next retaining pile.

[0038] Preferably, in step S45, the pile hole is backfilled with solid sulfide soil, and the filling is carried out on site by pumping, with a flow value of 160mm to 180mm, a water seepage rate of ≤1.5%, and a wet density of not less than 1700kg / m3; test blocks must be retained on site for testing, and the 28-day compressive strength must be not less than 1.2MPa; and the setting time should be controlled within 24h.

[0039] Preferably, in step S47, the position of the next retaining pile is selected to be constructed by intermittent pile skipping, and the pile body is removed at intervals of four retaining piles.

[0040] Compared with the prior art, the beneficial effects of the present invention include:

[0041] The underground obstacle handling structure of the present application is combined with the construction method. Before pulling out the piles, temporary steel pipe piles are set up for retaining soil, and the slope of the site is cut and leveled, which can effectively solve the problem of removing pile foundation obstacles in the slope environment, and at the same time reduce the impact of the pile pulling operation on the existing underground municipal facilities; the use of MJS reinforcement bodies to reinforce the adjacent risk sources can reduce the deformation and settlement effects of the soil unloading effect of the pile pulling operation on the adjacent risk sources; before the shield passes through, the full-rotation pile pulling construction process is used to remove the pile foundation that conflicts with the shield tunnel, and solid fluidized soil is used to backfill the pile hole, reducing the construction risk of the shield grinding pile and ensuring the smooth construction of the shield. The underground obstacle handling structure and construction method are simple and feasible, safe and reliable, and can play a good protective role for existing municipal facilities and adjacent risk sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0043] Figure 1 It is an internal schematic diagram of the underground obstacle handling structure of the present invention in the front view direction.

[0044] Figure 2 It is an internal schematic diagram of the underground obstacle handling structure of the present invention when viewed from above.

[0045] in:

[0046] 1-slope, 2-underground structures, 3-concrete force transfer belt, 4-crown beam, 5-retaining piles, 6-shield tunnel, 7-steel pipe piles, 8-MJS reinforcement body, 9-pile hole backfill, 10-risk source. DETAILED DESCRIPTION

[0047] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. In the following description, many specific details are set forth in order to fully understand the present invention, and the embodiments described are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the art without making creative work are within the scope of protection of the present invention.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0049] Example:

[0050] See also Figure 1-Figure 2 , an underground obstacle treatment structure, including a slope 1, an underground structure 2, a concrete force transmission belt 3, a cap beam 4, a retaining pile 5, a shield tunnel 6, a steel pipe pile 7, an MJS reinforcement body 8, a pile hole backfill 9 and a risk source 10;

[0051] The underground structure 2, the concrete force transmission belt 3, the cap beam 4, the retaining pile 5, the shield tunnel 6, the steel pipe pile 7, the MJS reinforcement body 8, and the pile hole backfill 9 are arranged in the soil of the slope 1, and the risk source 10 is located on one side of the soil of the slope 1;

[0052] The retaining piles 5 are arranged around the underground structure 2, and the concrete force transmission belt 3 is arranged between the retaining piles 5 and the underground structure 2;

[0053] The shield tunnel 6 is arranged below the retaining piles 5 and the underground structure 2, and the shield tunnel 6 and the retaining piles 5 are arranged in conflict with each other, that is, the bottom of the retaining piles 5 intrudes into the shield tunnel 6;

[0054] The MJS reinforcement body 8 is arranged between the risk source 10 and the shield tunnel 6;

[0055] The steel pipe pile 7 is arranged between the MJS reinforcement body 8 and the retaining pile 5;

[0056] The pile hole backfill material 9 is arranged around the retaining pile 5 , and the cap beam 4 is arranged on the top of the retaining pile 5 .

[0057] In the underground obstacle treatment structure of this embodiment, the slope 1 is a structure with a certain height difference after the underground construction is completed, and the top plate is backfilled to the site elevation; the risk source 10 is a structure that needs to be protected during the removal operation of the adjacent retaining pile 5, and the foundation form is a shallow foundation, pile foundation, etc. The structure of the set steel pipe pile 7 plays a role of retaining soil when the site is cut and leveled before the pile extraction operation, which can effectively solve the problem of removing pile foundation obstacles in the slope 1 environment, and at the same time reduce the impact of the pile extraction operation on the existing underground municipal facilities. The set MJS reinforcement body 8 reinforces the adjacent risk source 10, which can reduce the deformation and settlement effect of the pile extraction operation on the adjacent risk source 10.

[0058] The underground construction 2 of this embodiment is a reinforced concrete structure buried underground, and common ones are pipe jacking shafts, underground pipe galleries or underground tunnels.

[0059] The retaining piles 5 of this embodiment are reinforced concrete structures, and the pile diameter of the retaining piles 5 is 600mm, 800mm or 1000mm. The retaining piles 5 are arranged around the underground structure 2. More specifically, the retaining piles 5 are arranged around the foundation pit, and they are the retaining structures required for foundation pit excavation. The underground obstacles to be dealt with in this embodiment are the structures of the retaining piles 5. The retaining piles 5 that conflict with the shield tunnel 6 are removed, and the removal range is from the pile top to 2m below the bottom of the shield tunnel 6.

[0060] The shield tunnel 6 of this embodiment includes a plurality of lining units of reinforced concrete structures connected end to end in a circular shape. The concrete of the lining units is C50 concrete. The bottom of the retaining piles 5 corresponding to the position of the shield tunnel 6 is located in the shield tunnel 6.

[0061] Specifically, the retaining piles 5 surrounding the underground structure 2 form a closed retaining body. The shape of the retaining body in this embodiment is the same as the shape of the foundation pit, which is a square structure, and can also be other shapes;

[0062] The material of the steel pipe pile 7 of this embodiment is Q235 steel. Several steel pipe piles 7 are arranged along the extension direction of one side of the square enclosure and exceed the two ends of one side of the square enclosure. The specific exceeding range is 3m. The top height of the steel pipe pile 7 is higher than the top height of the square enclosure. The distance between the steel pipe pile 7 and one side of the square enclosure is 1m. The outer diameter of the steel pipe pile 7 is 630mm, the wall thickness is 10mm, and the spacing between adjacent steel pipe piles 7 is 700mm.

[0063] The MJS reinforcement body 8 of this embodiment is a high-pressure rotary jet pile, and several high-pressure rotary jet piles are arranged along the extension direction of one side of the square enclosure. The pile diameter of the MJS reinforcement body 8 is 2200mm, the bite is 600mm, and the spacing between adjacent MJS reinforcement bodies 8 is 1600mm. The grouting of the MJS reinforcement body 8 uses 42.5MPa ordinary Portland cement, the water-cement ratio is 1.0~1.1, the cement content is 40%, and the 28-day unconfined compressive strength qu>1.5MPa.

[0064] The pile hole backfill material 9 of this embodiment is backfilled with fluidized solidified soil for the pile extraction hole formed by the retaining pile 5 .

[0065] The concrete force transmission belt 3 of this embodiment is C35 plain concrete, with a length of 1 m, and is cast simultaneously with the bottom plate of the underground structure 2 to play a temporary force transmission role during the foundation pit excavation stage.

[0066] The present invention also includes a construction method of an underground obstacle treatment structure, which is applied to the above-mentioned underground obstacle treatment structure and includes the following steps:

[0067] S1. The soil between the risk source 10 and the shield tunnel 6 is reinforced with MJS reinforcement body 8. The MJS reinforcement body 8 is a high-pressure jet grouting pile. The two ends of the length direction formed by the arrangement of several MJS reinforcement bodies 8 exceed the boundary of the risk source 10 by 3m each. The pile diameter of the MJS reinforcement body 8 is 2200mm, the bite is 600mm, and the spacing between adjacent MJS reinforcement bodies 8 is 1600mm. The grouting of the MJS reinforcement body 8 uses 42.5MPa ordinary silicate cement, the water-cement ratio is 1.0-1.1, the cement content is 40%, and the 28-day unconfined compressive strength qu>1.5MPa. The grouting pressure should be gradually increased from low to high, and the specific value should be adjusted accordingly according to the test pile effect. Before drilling the jet grouting pile, the pile position should be laid out according to the jet grouting pile plan layout. The drilling plane position deviation should be ≤50mm, the drilling slope should be ≤1 / 200, the drilling depth deviation should be ≤150mm, and the pile angle error should be controlled to be no more than 1 / 100.

[0068] S2. Driving steel pipe piles 7 outside the retaining piles 5 for retaining support. The length of the retaining piles 5 is determined based on the stability calculation of the slope 1.

[0069] S3. Excavate the slope 1 corresponding to the underground structure 2, specifically excavate the slope according to the slope ratio of 1:2, excavate until the crown beam 4 is exposed and remove the crown beam 4 to expose the pile position of the retaining pile 5, then level the excavated site to facilitate the subsequent leveling and stability of the construction site after the mechanical equipment enters, and take safety protection measures for the existing facilities and pedestrians;

[0070] S4, full-rotation obstacle removal and pile pulling construction is performed on the pile position of the retaining pile 5, and the pile body of the retaining pile 5 is pulled out. In step S4, the steps of full-rotation obstacle removal and pile pulling construction are as follows:

[0071] S41, pressing the steel sleeve into place to a predetermined depth;

[0072] S42, punching and drilling holes by using a full-rotation drilling rig;

[0073] S43, twisting and breaking the retaining pile 5 in sections;

[0074] S44. Go to the designed removal elevation and remove the five segments of the twisted retaining piles;

[0075] S45. Backfill the pile hole formed at the pile position of the retaining pile 5. Use solid sulfide soil to backfill the pile hole. Pumping is used on site. The flow value is 160mm to 180mm, the water seepage rate is ≤1.5%, and the wet density should not be less than 1700kg / m3. Test blocks must be retained on site for testing. The 28-day compressive strength should not be less than 1.2MPa. The setting time should be controlled within 24h.

[0076] S46, remove the steel sleeve;

[0077] S47, repeat the above steps to pull out the next retaining pile 5. Specifically, the position of the next retaining pile 5 is selected to adopt the interval pile jumping construction, and the pile body is pulled out at intervals of four retaining piles 5.

[0078] S5. After all the retaining piles 5 that conflict with the shield are removed and backfilled, secondary grouting is carried out in the tunnel within 1m outside the segment structure of the shield tunnel 6.

[0079] In summary, the underground obstacle handling structure of the present application is combined with the construction method. Before pulling out the piles, temporary steel pipe piles 7 are set up for retaining soil, and the slope of the site is cut and leveled, which can effectively solve the problem of removing pile foundation obstacles in the slope 1 environment, and at the same time reduce the impact of the pile pulling operation on the existing underground municipal facilities; the MJS reinforcement body 8 is used to reinforce the adjacent risk source 10, which can reduce the deformation and settlement of the adjacent risk source 10 caused by the soil unloading effect of the pile pulling operation; before the shield passes through, the full-rotation pile pulling construction process is used to remove the pile foundation that conflicts with the shield tunnel 6, and solid fluidized soil is used to backfill the pile hole, which reduces the construction risk of the shield grinding pile and ensures the smooth construction of the shield. The underground obstacle handling structure and construction method are simple and feasible, safe and reliable, and can play a good protective role for existing municipal facilities and adjacent risk sources 10.

[0080] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. An underground obstacle handling structure, characterized in that: Including slopes, underground structures, concrete force transmission belts, cap beams, retaining piles, shield tunnels, steel pipe piles, MJS reinforcements, pile hole backfill and risk sources; The underground structures, concrete force transmission belts, cap beams, retaining piles, shield tunnels, steel pipe piles, MJS reinforcement bodies, and pile hole backfill are arranged in the soil of the slope, and the risk source is located on one side of the soil of the slope; The retaining piles are arranged around the underground structure, and the concrete force transmission belt is arranged between the retaining piles and the underground structure; The shield tunnel is arranged below the retaining piles and underground structures, and the shield tunnel is arranged to conflict with the retaining piles; The MJS reinforcement body is arranged between the risk source and the shield tunnel; The steel pipe pile is arranged between the MJS reinforcement body and the retaining pile; The pile hole backfill material is arranged around the retaining pile, and the cap beam is arranged on the top of the retaining pile.

2. The underground obstacle handling structure according to claim 1, characterized in that: The underground construction is a pipe jacking shaft, an underground pipe gallery or an underground tunnel.

3. The underground obstacle handling structure according to claim 1, characterized in that: The retaining piles are reinforced concrete structures, and the pile diameters of the retaining piles are 600mm, 800mm or 1000mm.

4. The underground obstacle handling structure according to claim 1, characterized in that: The shield tunnel comprises a plurality of lining units of reinforced concrete structure connected end to end in a circular shape, the concrete of the lining units is C50 concrete, and the bottom of the retaining pile corresponding to the position of the shield tunnel is located in the shield tunnel.

5. The underground obstacle handling structure according to claim 1, characterized in that: The retaining piles arranged around the underground structure form a closed retaining body; The steel pipe piles are made of Q235 steel. Several of the steel pipe piles are arranged along the extension direction of one side of the square enclosure and beyond the two ends of one side of the square enclosure. The top height of the steel pipe piles is higher than the top height of the square enclosure.

6. The underground obstacle handling structure according to claim 5, characterized in that: The MJS reinforcement body is a high-pressure jet grouting pile, and a plurality of the high-pressure jet grouting piles are arranged along the extension direction of one side of the square enclosure.

7. A construction method for an underground obstacle treatment structure, characterized in that: The underground obstacle treatment structure applied to the above claims 1-6 comprises the following steps: S1. Use the MJS reinforcement body to reinforce the soil between the risk source and the shield tunnel; S2, driving the steel pipe piles outside the retaining piles for retaining support; S3. Excavate the slope corresponding to the underground structure until the top beam is exposed and then remove the top beam to expose the pile position of the retaining pile, and then level the excavated site; S4. Perform full-turn obstacle removal and pile pulling construction at the pile position of the retaining pile, and remove the pile body of the retaining pile; S5. Carry out secondary grouting inside the tunnel within 1m outside the segment structure of the shield tunnel.

8. The construction method of the underground obstacle treatment structure according to claim 7, characterized in that: In step S4, the steps of full-rotation obstacle removal and pile removal construction are as follows: S41, pressing the steel sleeve into place to a predetermined depth; S42, punching and drilling holes by using a full-rotation drilling rig; S43, twisting and breaking the retaining piles in sections; S44. Go to the designed removal elevation and remove the broken retaining pile segment; S45, backfilling the pile hole formed at the pile position of the retaining pile; S46, remove the steel sleeve; S47, repeat the above steps to pull out the next retaining pile.

9. The construction method of the underground obstacle treatment structure according to claim 8, characterized in that: In step S45, the pile hole is backfilled with solid sulfide soil, and the filling is carried out on site by pumping. The flow value is 160mm to 180mm, the water seepage rate is ≤1.5%, and the wet density should not be lower than 1700kg / m3; test blocks must be retained on site for testing, and the 28-day compressive strength must not be lower than 1.2MPa; the setting time should be controlled within 24h.

10. The construction method of the underground obstacle treatment structure according to claim 8, characterized in that: In step S47, the interval skipping construction is selected for the position of the next retaining pile, and the pile body is removed at intervals of four retaining piles.

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