A method for top-pushing construction of a box culvert over a subway

Abstract

The present invention relates to a box culvert top-pushing construction method for a subway, comprising the following steps: step S101, construction of a support system: constructing a support system in front of the box culvert and above the existing subway; setting a slide plate at the bottom end of the starting position of the box culvert along the top-pushing direction, and the box culvert slides on the slide plate; performing several grouting reinforcements on the soil in front of the box culvert and above the existing subway; step S103, box culvert top-pushing construction: installing a counterweight assembly at the top end of the box culvert, and adjusting the installation position of the counterweight assembly on the box culvert as the box culvert is pushed forward. The high-pressure jet grouting piles and support piles of this top-pushing construction method can limit the top-pushing direction of the box culvert to avoid the box culvert from shifting during the top-pushing process; deep hole grouting reinforcement is performed on the soil at the bottom ends of several high-pressure jet grouting piles and several support piles, and dense grouting reinforcement is performed on the weak stress-bearing parts of the soil, so that the high-pressure jet grouting piles, support piles, and grouting reinforcement areas form a U-shaped structure reinforcement system.

Description

Technical Field

[0001] The invention belongs to the technical field of box culvert construction, relates to the jacking construction of a box culvert, and in particular to a jacking construction method for a box culvert that crosses a subway. Background Art

[0002] The construction of underground pipelines generally adopts open excavation, pipe pushing, horizontal directional drilling, and jacking methods. When the construction pipeline needs to cross existing roads or existing pipelines, the jacking method is a construction method with high efficiency, simple operation, and no impact on the operation of existing pipelines and roads. It has been widely used. However, there are still the following problems in the jacking construction of box culverts across subways:

[0003] 1. As an important transportation hub, the subway cannot be stopped during construction. Like the box culvert, it is an underground project and is close to the box culvert. During the jacking construction, the disturbance of the surrounding soil has a great impact on the subway, which is likely to cause the subway to float and the surrounding surface to settle.

[0004] 2. During the top-pushing construction, counterweights will be set on the box culvert. When the box culvert moves to different positions, different counterweights will be applied. Traditional counterweight removal uses a crane to directly lift and move the counterweights. However, during the crane lifting process, the weight of the box culvert counterweight is reduced, which is not conducive to controlling the settlement of the subway, resulting in safety and quality risks in the construction.

[0005] 3. During the jacking construction, it is necessary to break the supporting piles on both sides of the box culvert. Usually, a rope saw is used for cutting. Before cutting, holes need to be drilled on the supporting piles. Due to the particularity of the subway overpass, the drilling time needs to be reduced as much as possible. However, the drilling process is easily affected by the bulging of the supporting piles and the uneven surface, resulting in a long time to determine the drilling position and drilling depth, wasting construction time.

[0006] Therefore, we propose a box culvert jacking construction method over the subway to solve the above problems. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a box culvert jacking construction method for a subway with high construction quality and small soil disturbance.

[0008] To solve the above problems, the technical solution of the present invention is:

[0009] A method for top-pushing construction of a box culvert over a subway comprises the following steps:

[0010] Step S101, construction support system:

[0011] Construct a support system in front of the box culvert and above the existing subway;

[0012] A slide plate is arranged at the bottom end of the starting position of the box culvert along the pushing direction, and the box culvert slides on the slide plate;

[0013] Carry out several grouting reinforcements on the soil in front of the box culvert and above the existing subway;

[0014] Step S103: Box culvert jacking construction:

[0015] Install the counterweight assembly at the top of the box culvert, and adjust the installation position of the counterweight assembly on the box culvert as the box culvert is pushed forward.

[0016] In a further embodiment, in step S101, in constructing a support system, the support system includes a plurality of high-pressure jet grouting piles and a plurality of support piles arranged in sequence;

[0017] The areas reinforced by several grouting are located at the bottom ends of several high-pressure jet jet piles and several supporting piles.

[0018] In a further embodiment, the front of the slide plate is a primary grouting reinforcement area, and the soil range located in front of the slide plate and half the box culvert length away from the slide plate is a secondary grouting reinforcement area.

[0019] In a further embodiment, a plurality of grouting pipes are fixedly installed in both side ends and the bottom end of the box culvert;

[0020] A bow slope is arranged at the bottom end of the front end of the culvert, which is suitable for pushing forward.

[0021] In a further embodiment, in step S103, during the box culvert jacking construction, the counterweight assembly includes a plurality of slide rails and a plurality of movable counterweight blocks, a plurality of slide rails are fixedly installed at intervals on the top surface of the box culvert, a plurality of movable counterweight blocks are slidably installed on the slide rails, and a plurality of fixed counterweight blocks are also installed on the top surface of the box culvert;

[0022] A winch is fixedly installed at the front end of the slide rail, and the winch connects all the movable counterweights located on the same slide rail.

[0023] In a further embodiment, limiting members are fixedly installed on both sides of the top surface of the box culvert, and an intercepting rod is fixedly installed between a pair of limiting members, which is suitable for limiting the sliding of the movable counterweight block during jacking construction.

[0024] In a further embodiment, when one-half of the box culvert moves out of the slide plate, a plurality of movable counterweights are located at the rear end of the box culvert;

[0025] When two-thirds of the box culvert moves out of the slide plate, a number of movable counterweights are located in the middle of the box culvert;

[0026] When the box culvert is completely moved out of the slide plate, a number of movable counterweights are evenly arranged on the top surface of the box culvert.

[0027] In a further embodiment, a crown beam is provided at the top end of the supporting pile, and a supporting pile positioning device is installed on the crown beam and the top end of the supporting pile, which is suitable for positioning and measuring the drilling construction position during jacking construction and when cutting the supporting pile.

[0028] In a further embodiment, a plurality of telescopic members are fixedly installed at intervals on the support pile positioning device, suitable for adjusting the size of the support pile positioning device;

[0029] The supporting pile positioning device comprises a plurality of rods, and the telescopic member is sleeved outside the connection position of two adjacent rods.

[0030] In a further embodiment, one end of the telescopic member is fixedly mounted on the end of a rod, and a plurality of extension rulers are slidably mounted in the other end of the telescopic member, and the innermost extension ruler is slidably mounted on the end of another rod;

[0031] Adjust the length of the telescopic piece by pulling out several extension rulers.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. This jacking construction method constructs several high-pressure jet grouting piles and several supporting piles in front of the box culvert and above the existing subway to limit the jacking direction of the box culvert, avoid the box culvert from shifting during the jacking process, and ensure the accurate installation position of the box culvert; deep hole grouting reinforcement is carried out on the soil at the bottom ends of several high-pressure jet grouting piles and several supporting piles, and dense grouting reinforcement is carried out on the weak stress points of the soil, so that the high-pressure jet grouting piles, supporting piles, and grouting reinforcement areas form a U-shaped structure reinforcement system, which can reduce the uplift of the existing subway and the surrounding surface settlement, reduce the risk of sinking and shifting of the box culvert during the jacking process, and improve the construction quality.

[0034] 2. In this jacking construction method, when half of the box culvert slides out of the slide plate, the mobile counterweight blocks are centrally arranged at the rear end of the box culvert to prevent the box culvert from sinking; when two-thirds of the box culvert slides out of the slide plate, the mobile counterweight blocks are moved to the middle of the box culvert; when the box culvert completely slides out of the slide plate, the mobile counterweight blocks are evenly arranged; through the cooperation of the winch and the slide rail, the mobile counterweight blocks can be moved without lifting and are always located on the box culvert, ensuring that the box culvert can slide out of the slide plate smoothly, facilitating the control of the box culvert posture and improving the construction quality.

[0035] 3. In this jacking construction method, a supporting pile positioning device is fixedly installed on the crown beam of the supporting pile. Telescopic parts are installed on the four sides of the supporting pile positioning device, which are suitable for adjusting the size of the supporting pile positioning device so that the bottom end of the supporting pile positioning device abuts against the two side surfaces of the supporting pile, thereby positioning the drilling position of the rope saw cutting; a plurality of extension rulers are slidably mounted in the telescopic part, which are suitable for adjusting the length of the telescopic part, and then adjusting the size of the supporting pile positioning device. The extension rulers are marked with scales and values, which can quickly and conveniently read the data to obtain the drilling depth, thereby ensuring one-time drilling and reducing drilling time.

[0036] 4. In this jacking construction method, several grouting pipes are fixedly installed at intervals at the ends and bottom of both sides of the box culvert. When the elevation settlement of the box culvert is large, the surrounding soil layer can be hardened by grouting through the grouting pipes, and the elevation correction of the box culvert can also be carried out to ensure the accurate position of the box culvert. The type of grouting slurry can be changed according to needs, such as drag-reducing mud, etc., which is flexible and convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a flow chart of a method for top-pushing construction of a box culvert over a subway;

[0038] Figure 2 It is a top view of a method for top-pushing construction of a box culvert over a subway;

[0039] Figure 3 It is a side view of a method for top-pushing construction of a box culvert over a subway;

[0040] Figure 4 This is a front view of a box culvert top-pushing construction method that crosses a subway;

[0041] Figure 5 A schematic diagram of the bow slope of a box culvert top-pushing construction method over a subway;

[0042] Figure 6 A side view of a box culvert grouting pipe in a box culvert top-pushing construction method over a subway;

[0043] Figure 7 It is a front cross-sectional view of a box culvert grouting pipe in a box culvert top-pushing construction method over a subway;

[0044] Figure 8 A schematic diagram of a counterweight assembly for a method of top-pushing construction of a box culvert over a subway;

[0045] Fig. 9 It is a front view of a mobile counterweight block in a method of top-pushing construction of a box culvert over a subway;

[0046] Fig.10 A side view of a mobile counterweight block in a method for pushing a box culvert across a subway;

[0047] Fig.11 A top view of a counterweight assembly for a box culvert top-pushing construction method over a subway;

[0048] Fig.12 This is one of the schematic diagrams of step S103 of a method for top-pushing construction of a box culvert over a subway;

[0049] Fig.13 This is a second schematic diagram of step S103 of a method for top-pushing a box culvert across a subway;

[0050] Fig.14 This is a third schematic diagram of step S103 of a method for top-pushing a box culvert across a subway;

[0051] Fig.15 A schematic diagram of a support pile positioning device for a box culvert top-pushing construction method over a subway;

[0052] Fig.16 A schematic diagram of telescopic parts for a method of top-pushing construction of a box culvert over a subway.

[0053] In the figure: 1. Existing subway; 2. Primary grouting reinforcement area; 3. High-pressure jet jet piles; 4. Support piles; 41. Crown beam; 5. Slide plate; 6. Box culvert; 61. Bow slope; 62. Grouting pipe; 7. Existing soil; 8. Secondary grouting reinforcement area; 9. Counterweight assembly; 91. Limiting piece; 92. Slide rail; 93. Fixed counterweight block; 94. Mobile counterweight block; 941. Slide; 95. Interceptor rod; 96. Winch; 10. Support pile positioning device; 11. Telescopic piece; 111. Extension ruler; H, box culvert length; L1, crown beam width; L2, left difference; L3, right difference. DETAILED DESCRIPTION

[0054] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0055] Embodiment 1:

[0056] A method for top-pushing construction of a box culvert over a subway station, such as Figures 1 to 16 As shown, the following steps are included:

[0057] S101. Construction support system

[0058] like Figures 2 to 4 Before the top-pushing construction, a slide plate 5 is fixedly installed at the bottom end of the starting position of the box culvert 6, and deep hole grouting reinforcement is performed on the soil located in front of the box culvert 6, above the existing subway 1, and below the existing soil 7. The area for deep hole grouting reinforcement is the primary grouting reinforcement area 2, and the primary grouting reinforcement area 2 is located in front of the slide plate 5 and connected to the slide plate 5; since the existing subway 1 is in use, in order to ensure the normal operation of the subway, the grouting process is mainly controlled by grouting pressure, and the grouting volume control is supplemented. The grouting pressure is 0.8Mpa, and the drilling holes for deep hole grouting are arranged in a plum blossom shape. The spacing between adjacent drilling holes is 1.8m. The drill rod retreat grouting construction process is adopted. The reinforcement slurry uses cement single liquid slurry, and the cement uses P.042.5 grade ordinary Portland cement. Different slurry ratios are adopted according to different stratum conditions. The specific slurry ratio and stratum relationship are detailed in Table 1:

[0059] Table 1 Slurry ratios for different formations

[0060]

[0061] When the front half of the box culvert 6 pushes out the slide plate 5, because there is an existing subway 1 below, the soil at the front end of the box culvert 6 is subjected to concentrated stress and is a weak point. In order to reduce the impact of stress concentration on the existing subway 1 during construction, the soil at the weak point is reinforced by dense grouting. The area for dense grouting reinforcement is the secondary grouting reinforcement area 8. The secondary grouting reinforcement area 8 is at half the box culvert length H in front of the slide plate 5, and is expanded by 5m in front and behind. The grouting pressure of the dense exploration hole grouting is 0.8Mpa. The exploration holes are arranged in a plum blossom shape, and the distance between adjacent boreholes is 1m. The dense grouting parameters are shown in Table 1.

[0062] along Figure 2 , Figure 4In the pushing direction of the middle arrow, a support system is constructed on both sides in front of the box culvert 6 and above the existing subway 1, which is convenient for limiting the travel direction of the box culvert 6, ensuring that the box culvert 6 is accurately positioned during the construction process, and improving the construction quality; the support system includes a plurality of support piles 4 and a plurality of high-pressure rotary jet piles 3, and the plurality of support piles 4 are symmetrically arranged on both sides in front of the box culvert 6, and the plurality of support piles 4 located close to the box culvert 6 are arranged horizontally, so that the plurality of support piles 4 form an L-shaped structure when viewed from above, and the plurality of high-pressure rotary jet piles 3 are located in front of the plurality of support piles 4 and connected to the plurality of support piles 4, and the bottom of the plurality of support piles 4 The ends are located at the bottom ends of the primary grouting reinforcement area 2 and the secondary grouting reinforcement area 8, and the bottom ends of the plurality of high-pressure rotary jet piles 3 are located at the top ends of the primary grouting reinforcement area 2 and the secondary grouting reinforcement area 8, so that the plurality of high-pressure rotary jet piles 3, the plurality of supporting piles 4, the primary grouting reinforcement area 2, and the secondary grouting reinforcement area 8 form a U-shaped structure to provide comprehensive three-dimensional reinforcement for the soil; the supporting piles 4 are bored cast-in-place piles, the diameter of the supporting piles 4 is 600mm, the spacing between adjacent supporting piles 4 is 1200mm, the effective pile length of the supporting piles 4 is 8.82m, the embedding depth is 5m, and the supporting piles 4 are 1.2m long. The guard pile 4 is provided with mesh steel bars with a diameter of 6mm and a spacing of 200mm×1200mm and C20 shotcrete wall protection. The cross-sectional size of the crown beam 41 of the support pile 4 is 800mm×600mm, and the strength grade of the concrete is C30. The support pile 4 adopts a D=150 prestressed anchor cable. The prestressed anchor cable adopts one pile and one anchor. When the anchor strength of the anchor cable reaches 15Mpa or reaches 75% of the design strength grade, the anchor cable can be tensioned and locked. The waist beam adopts 18a double I-beam in the anchor rod locking area; a number of high-pressure jet grouting piles 3 are arranged in two rows, using DN80 0 High-pressure jet grouting piles, the drilling depth is 10720mm, the empty drilling is 900mm, the effective length is 9820mm, the bite between two adjacent high-pressure jet grouting piles 3 is 25cm, to ensure that the two rows of high-pressure jet grouting piles 3 are filled densely, the high-pressure jet grouting piles 3 use ordinary Portland cement with a strength grade of P.042.5 or above, and the dosage of other admixtures and admixtures is determined through experiments to ensure that the reinforced soil has good uniformity and self-sustaining properties, and the unconfined compressive strength of the soil is not less than 0.8Mpa. The mix ratio parameters of high-pressure jet grouting piles 3 in different strata are shown in Table 2:

[0063] Table 2 Mix parameters of high pressure jet grouting piles in different strata

[0064]

[0065] The high-pressure rotary jet piles 3 and the supporting piles 4 can not only block the existing soil 7 on both sides in front of the box culvert 6 to prevent collapse, but also form a U-shaped support with the primary grouting reinforcement area 2 and the secondary grouting reinforcement area 8, which greatly increases the foundation bearing capacity of the soil at this location, supports the box culvert 6 during the jacking construction, and provides a safety guarantee for the jacking construction.

[0066] like Figure 6 , Figure 7 As shown, a plurality of grouting pipes 62 are arranged at intervals on both side ends and the bottom end of the box culvert 6. The grouting pipes 62 on both side ends of the box culvert 6 are arranged to penetrate along the direction of the box culvert 6. The direction of the grouting pipes 62 is the same as that of the box culvert 6. A grouting inlet is formed at the front end of the grouting pipe 62, and the grouting inlet is located on the front end surface of the box culvert 6. A plurality of grouting outlets are formed at intervals on the grouting pipe 62, and the plurality of grouting outlets are evenly distributed on the side end surface of the box culvert 6. The plurality of grouting pipes 62 located at the bottom end of the box culvert 6 are all arranged transversely, and the plurality of grouting pipes 62 are all provided with grouting inlets, and the grouting inlets are located on the inner bottom end surface of the box culvert 6. A plurality of grouting outlets are formed at intervals on the plurality of grouting pipes 62, and the plurality of grouting outlets are located on the inner bottom end surface of the box culvert 6. 6; the size, quantity and position of the grouting pipe 62 can be adjusted according to the actual construction conditions. In this embodiment, the diameter of the grouting pipe 62 is 5 cm. During the construction process, when the elevation settlement of the box culvert 6 is large, the grouting pipe 62 can be used to grout and harden the surrounding soil layer, and the elevation correction of the box culvert 6 can also be performed to ensure the accurate position of the box culvert 6. The grouting slurry type can be changed as needed. When the jacking force is too large, drag reducing mud can be selected. After the jacking construction is completed, the grouting inlet and outlet of the grouting pipe 62 are sealed with fine stone concrete, and the grouting inlet and outlet at the bottom end face of the box culvert 6 are plastered with mortar to prevent water leakage.

[0067] like Figure 5 As shown, in order to prevent the box culvert 6 from "plunging" during the jacking construction, an inclined bow slope 61 is formed on the bottom end surface of the front end of the box culvert 6. In different strata, the settlement of the box culvert 6 is different, so the angle of the bow slope 61 is different. The specific angles are shown in Table 3:

[0068] Table 3 Parameters of bow slope

[0069]

[0070] S103, box culvert 6 jacking construction

[0071] like Figures 8 to 14 As shown, during the jacking construction, a counterweight assembly 9 is installed at the top of the box culvert 6. The weight of the counterweight assembly 9 is 70% of the soil unloading weight M. The soil unloading weight M is calculated by formula (1), formula (2), and formula (3):

[0072] M = M1 - M2 (1)

[0073] M1=V1ρ (2)

[0074] M2=V2ρ (3)

[0075] Wherein, M is the unloading weight of the soil, M1 is the total weight of the soil excavated by jacking, M2 is the weight of the jacking structure, V1 is the volume of the excavated existing soil 7, ρ is the original soil density, and V2 is the volume of the box culvert 6.

[0076] like Figures 8 to 11 As shown, the counterweight assembly 9 includes a pair of limit members 91, a plurality of slide rails 92, a plurality of fixed counterweight blocks 93, a plurality of mobile counterweight blocks 94, an intercepting rod 95 and a plurality of winches 96. A plurality of slide rails 92 are fixedly installed at intervals on the top surface of the box culvert 6. A plurality of mobile counterweight blocks 94 are slidably installed on the plurality of slide rails 92. The setting principle of the mobile counterweight blocks 94 is to remove one and fill one. The mobile counterweight blocks 94 are rectangular structures. The two ends of the mobile counterweight blocks 94 are respectively provided with arc-shaped slide grooves 941, which are suitable for sliding on the slide rails 92. The front ends of the plurality of slide rails 92 are fixedly installed with winches 96. The winches 96 Connecting several mobile counterweights 94 on the corresponding slide rails 92, it is suitable for moving several mobile counterweights 94. Several fixed counterweights 93 are also fixedly installed on the top surface of the box culvert 6, and several fixed counterweights 93 do not need to be moved; the two sides of the top surface of the box culvert 6 are symmetrically fixedly installed with limiters 91, and a pair of limiters 91 are provided with several round holes at intervals, and the distance between adjacent round holes is 1m, which is suitable for wearing interception rods 95. The interception rods 95 are located above the slide rails 92 and in front of several mobile counterweights 94, and are suitable for limiting the position of several mobile counterweights 94 to prevent several mobile counterweights 94 from being displaced during the pushing process. Preferably, the limiters 91 and the slide rails 92 are made of I-beams.

[0077] like Figure 12 to Figure 14 As shown, when half of the box culvert length H of the box culvert 6 slides out of the slide plate 5, the box culvert 6 is prone to "diving", so a number of movable counterweights 94 are arranged at the rear end of the box culvert 6; when two-thirds of the box culvert length H of the box culvert 6 slides out of the slide plate 5, the box culvert 6 is prone to "raising its head", so a number of movable counterweights 94 are arranged in the middle of the box culvert 6; when the box culvert 6 completely slides out of the slide plate 5, a number of movable counterweights 94 are evenly arranged on the top surface of the box culvert 6; during the movement of a number of movable counterweights 94, a number of winches 96 start to pull in at the same time, pulling a number of movable counterweights 94 to a specified position, to ensure that the box culvert 6 slides out of the slide plate 5 smoothly.

[0078] like Fig.15 , Fig.16As shown, for the jacking project over the existing subway 1, it is very important to break the supporting piles 4 on both sides of the existing subway 1. Since the existing subway 1 is being put into use and the settlement of the existing subway 1 shall not exceed ±2mm, the supporting piles 4 on both sides are cut by a rope saw. Before the rope saw cutting, it is necessary to perform drilling construction on the supporting piles 4. In order to ensure the accuracy of the drilling position and reduce the drilling time as much as possible, a supporting pile positioning device 10 is installed on the crown beam 41 of the supporting pile 4. The bottom end of the supporting pile positioning device 10 is located at the drilling position of the supporting pile 4, which is suitable for locating the drilling position and marking the drilling depth L; the supporting pile positioning device 10 is a rectangular frame structure. Telescopic parts 11 are installed on the four sides of the supporting pile positioning device 10, which are suitable for adjusting the size of the supporting pile positioning device 10. The two sides of the supporting pile positioning device 10 are close to the two sides of the crown beam 41. The bottom end of the supporting pile positioning device 10 is located at the drilling position, and the bottom end of the supporting pile positioning device 10 is symmetrically pressed against the two side surfaces of the supporting pile 4. The top end of the supporting pile positioning device 10 is the crown beam width L1, the length of the left bottom end of the supporting pile positioning device 10 is the left difference L2, and the length of the right bottom end of the supporting pile positioning device 10 is the right difference L3. The drilling depth L can be calculated by formula (4):

[0079] L = L1- L2-L3 (4)

[0080] The support pile positioning device 10 includes a plurality of rods, and a telescopic member 11 is installed at the connection position of adjacent rods. The telescopic member 11 is a cylindrical structure, and one end of the telescopic member 11 is fixedly installed on the end of a rod by bolts. A plurality of extension rulers 111 are slidably installed in the other end of the telescopic member 11, and the end of another rod is slidably installed in the innermost extension ruler 111. The extension ruler 111 and the end of another rod are both provided with scale lines and values. The outer surfaces of the inner ends of the plurality of extension rulers 111 and the end of another rod are both provided with The ball is installed through the spring; the inner side surface of the outer end of the plurality of extension rulers 111 is formed with a groove, and the ball corresponds to the groove, so that when the rod of the support pile positioning device 10 is pulled, the rod drives the plurality of extension rulers 111 to move outward, and the ball is passively pressed downward until it moves to the groove and bounces up, thereby fixing the position of the extension ruler 111 and adjusting the length of the telescopic member 11. The length of the telescopic member 11 can be obtained through the scale and value on the extension ruler 111, thereby quickly obtaining the size of the support pile positioning device 10, which is convenient for calculating the drilling depth L. Preferably, the support pile positioning device 10 and the telescopic member 11 are made of aluminum alloy.

[0081] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for pushing construction of a box culvert over a subway, characterized in that: The following steps are involved: Step S101, construction support system: A support system is constructed in front of the box culvert (6) and above the existing subway (1) along the jacking direction; A slide plate (5) is arranged at the bottom end of the starting position of the box culvert (6), and the box culvert (6) slides on the slide plate (5); Performing several grouting reinforcements on the soil in front of the box culvert (6) and above the existing subway (1); Step S103: Box culvert (6) jacking construction: A counterweight assembly (9) is installed at the top end of the box culvert (6), and as the box culvert (6) is pushed forward, the installation position of the counterweight assembly (9) on the box culvert (6) is adjusted; The counterweight assembly (9) comprises a plurality of slide rails (92) and a plurality of movable counterweight blocks (94); the plurality of slide rails (92) are fixedly installed at intervals on the top surface of the box culvert (6); the plurality of movable counterweight blocks (94) are slidably installed on the slide rails (92); a plurality of fixed counterweight blocks (93) are also arranged on the top surface of the box culvert (6); a winch (96) is fixedly installed at the front end of the slide rail (92); the winch (96) is connected to all the movable counterweight blocks (94) located on the same slide rail (92); Limiting members (91) are fixedly installed on both sides of the top surface of the box culvert (6), and an intercepting rod (95) is fixedly installed between a pair of the limiting members (91), which is suitable for limiting the sliding of the movable counterweight block (94) during the jacking construction; When one half of the box culvert (6) moves out of the slide plate (5), a plurality of the movable counterweight blocks (94) are located at the rear end of the box culvert (6); When two thirds of the box culvert (6) moves out of the slide plate (5), a plurality of the movable counterweight blocks (94) are located in the middle of the box culvert (6); When the box culvert (6) is completely moved out of the slide plate (5), a plurality of movable counterweight blocks (94) are evenly arranged on the top surface of the box culvert (6).

2. The method for pushing construction of a box culvert over a subway according to claim 1 is characterized in that: In the step S101, the support system is constructed, wherein the support system comprises a plurality of high-pressure jet grouting piles (3) and a plurality of support piles (4) arranged in sequence; The areas reinforced by the multiple grouting are located at the bottom ends of the multiple high-pressure jet grouting piles (3) and the multiple supporting piles (4).

3. The method for pushing construction of a box culvert over a subway according to claim 2 is characterized in that: The front of the slide plate (5) is a primary grouting reinforcement area (2), and the soil range located in front of the slide plate (5) and at a distance of half the box culvert length (H) from the slide plate (5) is a secondary grouting reinforcement area (8).

4. The method for pushing construction of a box culvert over a subway according to claim 3 is characterized in that: A plurality of grouting pipes (62) are fixedly installed in both side ends and the bottom end of the box culvert (6); A bow slope (61) is provided at the bottom end of the front end of the culvert (6), suitable for pushing forward.

5. The method for pushing construction of a box culvert over a subway according to claim 4 is characterized in that: A crown beam (41) is provided at the top end of the support pile (4), and a support pile positioning device (10) is installed on the crown beam (41) and at the top end of the support pile (4), which is suitable for positioning and measuring the drilling construction position during jacking construction and when cutting the support pile (4).

6. The method for pushing construction of a box culvert over a subway according to claim 5 is characterized in that: A plurality of telescopic parts (11) are fixedly installed at intervals on the support pile positioning device (10), which are suitable for adjusting the size of the support pile positioning device (10); The support pile positioning device (10) comprises a plurality of rods, and the telescopic member (11) is sleeved outside the connection position of two adjacent rods.

7. The method for pushing construction of a box culvert over a subway according to claim 6, characterized in that: One end of the telescopic member (11) is fixedly mounted on the end of one of the rods, and a plurality of extension rulers (111) are slidably mounted in the other end of the telescopic member (11), and the innermost extension ruler (111) is slidably mounted on the end of another of the rods; The length of the telescopic member (11) is adjusted by pulling out a plurality of extension rulers (111).

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