CN210975839U

CN210975839U - Narrow and small area underground structure supporting construction guiding device

Info

Publication number: CN210975839U
Application number: CN201921911236.5U
Authority: CN
Inventors: 魏邦仁; 赵德平; 董建民; 龚华; 杨毅; 夏伦学; 薛仰轶; 陈晨伟; 靳艳岳; 焦钘宇
Original assignee: Ascg Co ltd
Current assignee: Ascg Co ltd
Priority date: 2019-11-07
Filing date: 2019-11-07
Publication date: 2020-07-10
Anticipated expiration: 2029-11-07

Abstract

The utility model provides a construction guiding device is strutted to narrow and small area underground structure, the structure is: the intercepting well cuts off the original box culvert into a front section and a rear section; constructing an inner circle and an outer circle of high-pressure jet grouting piles at the periphery of the foundation pit of the intercepting well, and respectively inserting H-shaped steel in a close insertion mode and a one-by-one insertion mode; the outer ring high-pressure rotary spraying pile is arc-shaped, and two ends of the outer ring high-pressure rotary spraying pile are arranged right above the original box culvert at the front and rear sections and are connected with the inner ring high-pressure rotary spraying pile through full reinforcement of the high-pressure rotary spraying pile; arranging a reinforced concrete inner support between the inner and outer ring high-pressure jet grouting piles, and excavating between the piles to form a diversion trench foundation pit; the front and rear original box culverts are respectively provided with holes on the side wall and communicated with the diversion trench; the front and rear original box culverts respectively use the part right below the inserted H-shaped steel corresponding to the upper inner ring high-pressure jet grouting pile as a plugging part, a temporary plugging wall between the temporary plugging wall and the intercepting well is formed by underwater concrete, and bidirectional reinforcing steel bars are arranged in the wall. The utility model discloses have construction water conservancy diversion ability concurrently when satisfying the excavation supporting needs.

Description

Narrow and small area underground structure supporting construction guiding device

Technical Field

The utility model relates to a deep basal pit supporting construction and construction method, the more specifically narrow and small area underground structure supporting construction guiding device that says so.

Background

The deep foundation pit support of present urban rainwater, sewage box culvert reconstruction engineering, to supporting construction, construction water conservancy diversion mode that lateral wall of foundation ditch and all ring edge borders adopted, have following defect: 1. the single cement soil enclosure wall lacks bearing capacity and is large in stress deformation; 2. the soil squeezing is serious in the pile sinking process of the reinforced concrete sheet pile, the cost is high, the construction is not flexible, and the space limitation is large; 3. the cast-in-situ bored pile is not suitable for a small foundation pit, the quality is difficult to control, labor and time are wasted, and the hole forming speed is slow; 4. the traditional foundation pit support only has support bearing capacity and no construction flow guide capacity. Based on the above, the construction process for the existing deep foundation pit support is improved as follows:

the method comprises the steps of constructing an SMW construction method pile to form a water stop and enclosure system in the deep foundation pit support of the intercepting well, intercepting an old box culvert in a full-section blocking mode after the construction of the SMW construction method pile, then using a submersible pump to pump and drain water, excavating the foundation pit of the intercepting well, excavating to the top of the box culvert, constructing a supporting system in the foundation pit, continuously excavating to the bottom of a foundation pit of the intercepting well, constructing a main structure, and dismantling profile steel after the construction of a bottom plate and a bottom plate force transmission belt of the intercepting well is finished.

However, the construction process for supporting the deep foundation pit is often greatly limited by space due to inflexible construction, the concrete quality is difficult to control, labor and time are wasted, the hole forming speed is slow, and the construction period is delayed.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving above-mentioned technical problem to a certain extent at least. Therefore, the utility model provides a construction guiding device is strutted to narrow and small area underground structure to can have construction water conservancy diversion ability concurrently when satisfying the underground structure supporting needs in phase, thereby realize that the foundation ditch is stable, maintain original box culvert ability of overflowing.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the utility model provides a narrow and small area underground structure supporting construction guiding device which the structural feature is:

the intercepting well foundation pit forms a foundation pit supporting structure by using Larsen steel sheet piles and H-shaped steel inner supports, and an original box culvert is cut into a front section and a rear section by using the intercepting well;

constructing an inner circle and an outer circle of high-pressure jet grouting piles which are concentrically arranged and take the center of the intercepting well as the center of a circle on the periphery of the foundation pit of the intercepting well; inserting H-shaped steel into the inner-ring high-pressure jet grouting pile in a close-packed mode; the outer ring high-pressure jet grouting pile is arc-shaped, H-shaped steel is inserted in a one-to-one inserting mode, two ends of the H-shaped steel extend to the front and rear original box culverts respectively, and the H-shaped steel is connected with the inner ring high-pressure jet grouting pile through a full-space reinforced structural form of the high-pressure jet grouting pile right above the front and rear original box culverts; arranging reinforced concrete inner supports at set intervals along the circumferential direction between the inner and outer circles of high-pressure jet grouting piles, excavating between the inner and outer circles of high-pressure jet grouting piles to form a diversion trench foundation pit, forming a water-stop curtain by the inner and outer circles of high-pressure jet grouting piles, and forming a diversion trench foundation pit ring support supporting structure together with the reinforced concrete inner supports;

the front and rear original box culverts are respectively provided with holes on the side wall connected with the diversion trench and communicated with the diversion trench; the front and rear original box culverts respectively use the part under the H-shaped steel inserted in the high-pressure jet grouting pile corresponding to the upper inner ring as a plugging part, the plugging part forms a temporary plugging wall between the temporary plugging wall and the intercepting well by using underwater concrete, and bidirectional reinforcing steel bars connected with the box culvert top and bottom plates in a bar planting manner are arranged in the wall.

The utility model discloses a structural feature also lies in:

the distance between the bottom of the inner and outer ring high-pressure jet grouting pile located right above the box culvert and the top of the box culvert is 0.2m, and the high-pressure jet grouting pile is reinforced to the position 0.5m above the top of the box culvert.

The pile top and the waist of the inner and outer ring high-pressure jet grouting pile are respectively provided with a concrete crown beam and a concrete waist beam, and an upper reinforced concrete inner support and a lower reinforced concrete inner support are formed between the inner and outer ring concrete crown beams and the concrete waist beams.

The specifications of the inner and outer ring high-pressure jet grouting piles are phi 900@600, the specifications of the inserted H-shaped steel are 700X300X13X24mm, the specifications of the concrete crown beams are 1100 × 1000mm, the specifications of the upper reinforced concrete inner supports between the concrete crown beams are 600 × 600@2000, the specifications of the concrete waist beams are 600 × 600mm, the specifications of the lower reinforced concrete inner supports between the concrete waist beams are 400 × 500@2000, and the high-pressure jet grouting piles between the two ends of the outer ring high-pressure jet grouting pile and the inner ring high-pressure jet grouting pile are phi 700@400 to reinforce the whole space.

The plugging parts of the front and rear box culverts are temporary plugging walls formed by C25 underwater concrete with the thickness of 250mm, and 12@200 bidirectional steel bars are arranged in the walls.

Compared with the prior art, the utility model discloses beneficial effect embodies:

the utility model discloses a high pressure spouts pile interpolation H shaped steel with concrete ring brace's novel excavation supporting form soon forms outside guiding gutter foundation ditch between the inner and outer lane high pressure spouts pile stake soon including inserting H shaped steel to original state box culvert lateral wall trompil makes its and guiding gutter intercommunication, and then carries out the shutoff to the box culvert under its top inner circle high pressure spouts the H shaped steel of pile interpolation soon, with the mode of joining in marriage the bidirectional reinforcement in concrete formation temporary plugging wall, the wall under water. Under the prerequisite that does not influence the whole rigidity and the stability and the waterproof performance of enclosure, the utility model discloses the stagnant water effect that the stagnant water curtain that make full use of high-pressure jet grouting pile formed played, utilize the high strength of H shaped steel, rigidity simultaneously, rely on good bending resistance effectively to resist the deformation and the displacement of the foundation ditch outside soil body, satisfy supporting construction's bearing capacity and deformation control requirement, form the guiding gutter in order to maintain former box culvert throughput capacity and guarantee to satisfy construction water conservancy diversion requirement, when making to satisfy the excavation supporting requirement, have construction water conservancy diversion ability concurrently, provide a perfect transition when the corner is said or the interface for rivers management, the loss of head can significantly reduce in setting up of this guiding device, reduce the bend siltation, be favorable to making rivers smooth and straight after. The utility model discloses have effectual and the construction is swift, construction quality is high advantage, bring the disturbance less to building on every side, guarantee excavation in-process foundation ditch and close on the safety of building (structure).

Drawings

Fig. 1 is a schematic plan view of the present invention;

FIG. 2 is a schematic sectional view taken along the line A-A in FIG. 1;

fig. 3 is a schematic sectional view taken along the direction B-B in fig. 1.

In the figure, 1 intercepting well; 2, box culvert; 3, a diversion trench; 4, inner ring high-pressure jet grouting pile; 5, outer ring high-pressure jet grouting pile; 6 concrete crown beam; 7, concrete wale; 8, supporting in an upper reinforced concrete support; 9, supporting in reinforced concrete of the next track; 10 a bottom plate force transmission belt; 11 Larsen steel sheet piles; 12H-shaped steel purlin; supporting by 13H-shaped steel; 14, breaking a line of the box culvert; 15 plain concrete cushion layers; 16, a full-space reinforcing area of the high-pressure jet grouting pile; 17 temporarily plugging the wall.

Detailed Description

To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the embodiments of the present invention are combined to clearly and completely describe the technical solution in the embodiments of the present invention, and obviously, the described embodiments are some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Referring to fig. 1 to 3, the structure of the diversion device for supporting construction of the foundation pit in the narrow area of the embodiment is as follows:

a foundation pit of the intercepting well 1 forms a foundation pit supporting structure by using a Larsen steel sheet pile 11 and an H-shaped steel inner support, and an undisturbed box culvert 2 is cut off into a front section and a rear section by using the intercepting well 1;

constructing an inner circle and an outer circle of high-pressure rotary jet grouting piles which are concentrically arranged by taking the center of the intercepting well 1 as a circle center on the periphery of a foundation pit of the intercepting well 1; inserting H-shaped steel into the inner-ring high-pressure jet grouting pile 4 in a close-packed mode; the outer ring high-pressure jet grouting pile 5 is arc-shaped, H-shaped steel is inserted in a one-to-one inserting mode, two ends of the H-shaped steel respectively extend to the front and rear original-state box culverts 2, and the front and rear original-state box culverts 2 are connected with the inner ring high-pressure jet grouting pile 4 through a full-space reinforcing structural form of the high-pressure jet grouting pile; reinforced concrete inner supports are arranged between the inner and outer circles of high-pressure jet grouting piles 5 at a set interval along the circumferential direction, a diversion trench 3 foundation pit is formed by excavating between the inner and outer circles of high-pressure jet grouting piles, a water-stop curtain is formed by the inner and outer circles of high-pressure jet grouting piles, and a diversion trench 3 foundation pit ring support supporting structure is formed together with the reinforced concrete inner supports;

the front and rear original box culverts 2 are respectively provided with holes on the side wall connected with the diversion trench 3 and communicated with the diversion trench 3; the original box culvert 2 in the front and rear sections takes a part under the H-shaped steel inserted in the high-pressure jet grouting pile 4 corresponding to the upper inner ring as a plugging part, the plugging part forms a temporary plugging wall 17 between the temporary plugging wall and the intercepting well 1 by using underwater concrete, and a bidirectional steel bar connected with the top bottom plate of the box culvert 2 in a bar planting manner is arranged in the wall.

In specific implementation, the corresponding structural arrangement also includes:

the distance between the bottom of the inner and outer ring high-pressure jet grouting pile located right above the box culvert 2 and the top of the box culvert 2 is 0.2m, and the high-pressure jet grouting pile is reinforced to the position 0.5m above the top of the box culvert 2.

The top and waist of the inner and outer ring high-pressure jet grouting pile 5 are respectively provided with a concrete crown beam 6 and a concrete waist beam 7, and an upper reinforced concrete inner support and a lower reinforced concrete inner support are formed between the inner and outer ring concrete crown beams 6 and the concrete waist beam 7.

As mentioned above, the deep foundation pit support adopts high-pressure jet grouting pile inserted section steel and internal reinforced concrete support ring support, and is a novel construction scheme with construction diversion and deep foundation pit support capability, wherein the specifications of the internal and external ring high-pressure jet grouting piles 5 are phi 900@600, the specifications of the inserted H-shaped steel are 700X300X13X24mm, the specifications of the concrete top beams 6 are 1100 × 1000mm, the specification of the upper reinforced concrete inner support 8 between the concrete top beams 6 is 600 × 600@2000, the specification of the concrete waist beam 7 is 600 × 600mm, the specification of the lower reinforced concrete inner support 9 between the concrete waist beams 7 is 400 × 500@2000, the high-pressure jet grouting piles with 700 phi @400 are fully reinforced between the two ends of the external ring high-pressure jet grouting pile 5 and the internal ring high-pressure jet grouting pile 4, the radial center distance between the internal and external ring high-pressure jet grouting piles 5 is 2900 mm.

The plugging parts of the front and rear box culverts 2 are temporary plugging walls formed by C25 underwater concrete with the thickness of 250mm, and 12@200 bidirectional steel bars are arranged in the walls.

To city rainwater, 2 transformation engineering struts of sewage box culvert and the water conservancy diversion measure is optimized, utilize this device can realize both satisfying the excavation supporting requirement, have the water conservancy diversion ability again concurrently, keep off soil, stagnant water, the water conservancy diversion effect homoenergetic has good performance, the device construction takes up an area of for a short time, the time limit for a project is short, can be better be applicable to city rainwater, 2 transformation engineering of sewage box culvert, its construction method specifically can go on according to following step:

step 1, changing pipelines in advance, and clearing and leveling a field to an excavation design elevation; houses, current pipelines and the like are arranged on the periphery of the foundation pit, the burial depths of the house foundations and the pipelines are shallow, and the houses, the pipelines and the pipelines are moved in advance and cleaned and leveled;

step 2, constructing all high-pressure rotary jet grouting piles including a reinforcing area, wherein inner and outer ring high-pressure rotary jet grouting piles 5 which take the center of the intercepting well 1 as the center of a circle are constructed on the periphery of the position of a foundation pit of the intercepting well 1, H-shaped steel is respectively inserted in the inner ring high-pressure rotary jet grouting pile 5 in a mode of close insertion and one-jump insertion of the outer ring, and high-pressure rotary jet grouting piles are respectively constructed right above the front and rear original box culvert 2 between the two ends of the outer ring high-pressure rotary jet grouting pile 5 and the inner ring high-pressure rotary jet grouting pile 4 for full; cutting a soil body by using high-pressure gas, spraying cement slurry into the soil body through a rotating nozzle, mixing to form a cement-soil reinforcing body, and then inserting H-shaped steel to improve the bearing capacity of the structure;

step 3, digging a foundation pit of a diversion trench 3 between the inner and outer ring high-pressure jet grouting piles 5, and after the foundation pit of the diversion trench 3 is constructed, performing two reinforced concrete inner support constructions up and down between a crown beam and a waist beam on the inner and outer ring high-pressure jet grouting piles 5; thus, the support and the flow conductivity are considered;

step 4, after the inner support construction in the diversion trench 3 is finished, holes are formed in the original box culvert 2 at the front section and the original box culvert at the rear section according to the corresponding positions connected with the diversion trench 3, so that the original box culvert 2 at the front section and the original box culvert at the rear section are communicated with the diversion trench 3, the underwater concrete with the thickness of 250mm C25 is temporarily plugged at the position right below the inserted H-shaped steel in the high-pressure jet grouting pile 4 corresponding to the upper inner ring, a temporary plugging wall between the temporary plugging wall and the intercepting well 1 is formed, 12@200 bidirectional reinforcing steel bars are arranged in the wall, and the top bottom plates of the box culverts;

and 5, after the original box culvert 2 is perforated and the plugging measure construction is finished, excavating a foundation pit of the intercepting well 1 to the top of the box culvert 2, removing the original box culvert 2, constructing Larsen steel sheet piles 11 and H-shaped steel inner supports after residue is removed, then continuously excavating to the bottom of the foundation pit of the intercepting well 1, constructing a main structure, dismantling steel sheet pile supports after the construction of the bottom plate of the intercepting well 1 and the bottom plate force transmission belt 10 is finished, and continuously constructing the main structure until the construction is finished. The steel sheet pile is not pulled out in the later stage, and the H-shaped steel is pulled out according to the condition.

In the construction steps, the foundation pit excavation and supporting structure installation and removal sequence must strictly comply with the principles of first supporting and then excavation, time-limited supporting, segmented and layered excavation and strict overexcavation. The excavation thickness of each layer of non-mucky soil is not more than 1.5m, and the excavation thickness of each layer of mucky soil is not more than 1.0m according to the vertical spacing of the supports in each layer; the supporting time limit of each small section of excavation is not more than 24 hours; meanwhile, a catch basin or a water and soil retaining dam is arranged outside the slope top to prevent surface water from washing the slope surface and prevent drainage water outside the foundation pit from flowing back and permeating into the pit. The earth surface in the supporting range around the foundation pit is required to be maintained, protective railings, drainage measures and cement mortar or concrete ground are constructed, and earth surface rainfall is prevented from permeating underground.

In the step 2, P.0.42.5-grade ordinary portland cement is adopted for the high-pressure jet grouting pile, the diameter is 700/900mm, the lapping length among the piles is 300mm, the cement mixing amount is 25%, and the water cement ratio of cement slurry is 0.8 (which can be properly adjusted according to the soil layer condition on site). The standard value of unconfined compressive strength of the high-pressure jet grouting pile 28d is not less than 1.0Mpa, and the verticality deviation of the high-pressure jet grouting pile is not more than 1/150;

the high pressure rotary jet grouting pile construction adopts a triple pipe method, pressure control is carried out, wherein air pressure is not less than 0.7Mpa, cement slurry hydraulic pressure is preferably greater than 20Mpa, rotary jet lifting speed is 15-25cm/min, cement slurry flow is greater than 30L/min, when a grouting pipe is placed into a drill hole, a nozzle can spray grouting when reaching a design elevation, after the spraying grouting parameters reach specified values, the grouting pipe is lifted according to the technological requirements of the rotary jet grouting pile, grouting is sprayed from bottom to top, the rotating speed of a drill rod in the lifting process is 15-20r/min, and the overlapping length of subsection lifting of the grouting pipe is preferably greater than 100 mm.

In the step 2, the section steel insertion is carried out immediately after the cement-soil mixing pile mixing procedure is completed, and a positioning clamping die is installed before the insertion, so that the center of the positioning clamping die is consistent with that of the high-pressure jet grouting pile; generally, a self-weight sinking method is adopted for insertion, and when the self-weight sinking of the section steel cannot reach the designed elevation, a mechanical pressurization method can be adopted to enable the section steel to reach the sinking elevation; the sinking verticality is strictly ensured, and a method of combining a vertical chain hung on a pile foundation with theodolite vision measurement can be adopted to ensure that the verticality deviation is not greater than a specified value;

the section steel length is prepared according to engineering design, needs splice in advance when length can not satisfy the design requirement, and the groove welding is made to the concatenation department, and every is not more than 2 departments in the section steel joint, and should not be in the position of bending, receiving to cut big, makes two-way fishtail tenon in the middle part of connecting in case of necessity in order to strengthen the joint rigidity, and the face of weld should be unanimous with the former plane of section steel to guarantee to rise to draw and retrieve. The profile steel is lifted and pulled after the foundation pit construction is finished and backfilled, the profile steel is lifted and pulled one by one, a crown beam is used as a reaction force platform before the lifting and pulling, the profile steel is lifted and pulled firstly through a hydraulic jack, the profile steel is lifted and pulled slowly after being loosened, a crane is lifted and pulled after being lifted and pulled to a certain height, and the profile steel is lifted and pulled vertically during the lifting and pulling process, so that the lifting and pulling resistance is reduced, and the profile steel is kept not to deform. And forming a hollow hole in the high-pressure rotary jet grouting pile body after the section steel is pulled out, and timely refilling and filling with sand.

In step 3, the diversion trench 3 is filled with a C20 plain concrete cushion 15 with the thickness of 150 mm.

In the step 5, the bottom plate force transmission belt 10 is a C30 plain concrete force transmission belt and is integrally cast with the bottom plate of the intercepting well 1 in the same thickness.

In the step 5, a 9-meter-long FSP-IV type Larsen steel sheet pile 11 and an H-shaped steel inner support are used for supporting the foundation pit of the intercepting well 1, the H-shaped steel inner supports are connected among the Larsen steel sheet piles 11 through H-shaped steel purlins 12 with the specification of 700X300X13X24mm, and H-shaped steel supports 13 with the specification of 700X300X13X24mm form the inner supports. The joint of the H-shaped steel purlin 12 is welded into a whole.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. The utility model provides a narrow and small area underground structure supporting construction guiding device, characterized by:

2. The narrow zone foundation pit supporting construction guiding device of claim 1, which is characterized in that: the distance between the bottom of the inner and outer ring high-pressure jet grouting pile located right above the box culvert and the top of the box culvert is 0.2m, and the high-pressure jet grouting pile is reinforced to the position 0.5m above the top of the box culvert.

3. The narrow zone foundation pit supporting construction guiding device of claim 1, which is characterized in that: the pile top and the waist of the inner and outer ring high-pressure jet grouting pile are respectively provided with a concrete crown beam and a concrete waist beam, and an upper reinforced concrete inner support and a lower reinforced concrete inner support are formed between the inner and outer ring concrete crown beams and the concrete waist beams.

4. A foundation pit supporting construction diversion device in a narrow zone as claimed in any one of claims 1 to 3, wherein specifications of the inner and outer ring high-pressure jet grouting piles are phi 900@600, specifications of the inserted H-shaped steel are 700 × 300 × 13 × 24mm, specifications of the concrete crown beams are 1100 × 1000mm, specifications of the upper reinforced concrete inner support between the concrete crown beams are 600 × 600@2000, specifications of the concrete waist beams are 600 × 600mm, specifications of the lower reinforced concrete inner support between the concrete waist beams are 400 × 500@2000, and the two ends of the outer ring high-pressure jet grouting pile and the inner ring high-pressure jet grouting pile are reinforced in a full chamber by the phi 700@400 high-pressure jet grouting pile.

5. The narrow zone foundation pit supporting construction guiding device of claim 1, which is characterized in that: the plugging parts of the front and rear box culverts are temporary plugging walls formed by C25 underwater concrete with the thickness of 250mm, and 12@200 bidirectional steel bars are arranged in the walls.