CN111155782A - High-water-level existing basement pile foundation construction method - Google Patents

Abstract

The invention belongs to the field of basement structure dismantling and modification, and particularly relates to a high-water-level existing basement pile foundation construction method. The construction method sequentially comprises the following steps: the method comprises the steps of preparation before construction, floor slab reinforcement, hole opening, sleeve placement, pile-forming construction and sleeve recovery. The method disclosed by the invention at least has the following advantages: the floor is perforated by a water drill, so that noise pollution and dust pollution are reduced; the sleeve is used for drainage, so that the pollution of slurry to the existing basement structure in the traditional pile-repairing construction is avoided; the slurry generated by pile repair construction is treated by a mud-water separation system and then delivered out of a factory, so that the treatment efficiency is improved, and the pollution to the environment is reduced; the generated construction waste is less, and the construction waste is treated in a centralized clearing mode, so that the tidiness of a construction site is ensured; continuous precipitation is avoided, underground water resources are protected, and meanwhile, the influence on the surrounding environment is reduced.

Description

High-water-level existing basement pile foundation construction method

Technical Field

The invention belongs to the field of basement structure dismantling and modification, and particularly relates to a high-water-level existing basement pile foundation construction method.

Background

With the diversified development of the building market, the projects for carrying out function modification on the original building become more and more, and the accompanying structure modification work is carried out to make the construction difficulty in the original building function modification process.

At present, the existing basement structure is not subjected to a plurality of mature construction methods for dismantling and modifying the existing basement structure in the industry, particularly, the underground water level of the area is high, the pile repairing construction of the existing basement structure is required, the design bearing capacity of the original pile foundation cannot meet the requirement of a new structure after dismantling and modifying, the underground water level is controlled as the greatest construction difficulty, and the difficulties that the construction space is narrow, the pile forming verticality is difficult to control, the constructed structure is easy to damage and the like exist. Therefore, a high-water-level existing basement pile foundation construction method needs to be invented to ensure the overall construction quality of later-stage structure reconstruction.

Disclosure of Invention

The invention discloses a construction method of a high water level existing basement pile foundation, which enables confined water to achieve self-balance in a pipe by arranging a sleeve, avoids continuous precipitation, protects water resources and reduces the influence on the surrounding environment; and the pile filling construction is positioned on the top plate of the basement, so that the problem that the space for constructing the basement is narrow is solved.

Specifically, the technical scheme of the invention is as follows:

the invention discloses a high water level existing basement pile foundation construction method, which sequentially comprises the following steps: the method comprises the steps of preparation before construction, floor slab reinforcement, hole opening, sleeve placement, pile-forming construction and sleeve recovery.

Preferably, the preparation step before construction includes: pile position rechecking, pile position positioning and sleeve type selection.

More preferably, the pile position positioning method comprises the following steps: and (3) checking the drawing according to the pile position, measuring the pile position by using a total station and a steel ruler, marking the pile position by adopting a cross pile-bolting method, and protecting.

Preferably, the sleeve type selecting step comprises: the length of the sleeve is calculated before construction, and the shortest length L required by the sleeve in construction is more than or equal to s + d₁+d₂+ h, where s is the depth of insertion into the soil, d₁Is the thickness of the cushion layer, d₂The thickness of the bottom plate is, h is the depth of the basement, and the depth of the sleeve inserted into the soil body is required to be not less than 1.0 m.

Preferably, the sleeve is a steel sleeve.

Preferably, the floor slab reinforcing step includes: rechecking the construction load of the pile machine and the design bearing capacity of a structural top plate, and reinforcing the area needing to be reinforced; preferably, the floor in the construction range of the drilling machine is reinforced by adopting a disc buckle type scaffold, a profile steel return top and a steel plate reinforcing mode.

Preferably, the step of opening the hole comprises: and (3) drilling holes on the floor slab and the bottom plate, constructing by using water drilling holes, and arranging a plurality of water drilling holes in a circle by taking the pile site as the circle center.

Preferably, the sleeve placing step comprises: the sleeve is erected and then inserted into the lower layer of the bottom plate in a hoisting mode, the sleeve sinking construction is completed by adopting a hydraulic vibration hammer, a preset position is marked on the sleeve by using paint before sinking, the sleeve stops when in place, and then water stopping treatment is carried out.

More preferably, the water stop treatment step includes: and an annular water stop ring is welded at the joint of the sleeve and the bottom plate.

Preferably, the pile-forming construction step includes: in the drilling process of the pile machine, measuring the pile perpendicularity every 5 meters, and rechecking the pile perpendicularity after the pile is completed;

clear water is used for splitting the grouting pipe within 7-8 hours after the pile is formed, so that the grouting pipe is kept smooth; grouting is carried out after the pile is formed for 1.5 to 2.5 days.

Preferably, after the pile repairing construction is completed and about 4-5 hours (after the concrete is initially set) after the concrete is poured, reinforcing steel bars of the sleeve at the positions of all the floors are removed, a concrete pier for sealing the steel sleeve and the bottom plate is chiseled, and the water stop ring is cut off. And (4) pulling out the steel sleeve by adopting a hydraulic vibration hammer, and directly hanging the pulled-out steel sleeve to a next hole site for installation.

On the basis of the common general knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily without departing from the concept and the protection scope of the invention.

Compared with the prior art, the invention has the following remarkable advantages and effects:

(1) the floor is perforated by a water drill, so that noise pollution and dust pollution are reduced;

(2) the basement adopts the LED lamp strip to provide illumination, so that the energy consumption is reduced;

(3) the sleeve is used for drainage, so that the pollution of slurry to the existing basement structure in the traditional pile-repairing construction is avoided;

(4) the slurry generated by pile repair construction is treated by a mud-water separation system and then delivered out of a factory, so that the treatment efficiency is improved, and the pollution to the environment is reduced;

(5) the generated construction waste is less, and the construction waste is treated in a centralized clearing mode, so that the tidiness of a construction site is ensured;

(6) continuous precipitation is avoided, underground water resources are protected, and meanwhile, the influence on the surrounding environment is reduced.

Drawings

FIG. 1 is a schematic view of pile position positioning according to an embodiment of the present invention;

FIG. 2 is a schematic view of floor reinforcement according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of the arrangement of water drilling holes in the embodiment of the invention;

FIG. 4 is a schematic view of a sealing process in an embodiment of the present invention;

in the figure:

1-opening part, 2-disc buckle type scaffold, 3-section steel, 4-water drilling, 5-steel sleeve, 6-water stop ring, 7-bottom plate and 8-concrete.

Detailed Description

The technical solutions of the present invention are described in detail below with reference to the drawings and the embodiments, but the present invention is not limited to the scope of the embodiments.

Example 1

The invention discloses a high water level existing basement pile foundation construction method, which sequentially comprises the following steps: the method comprises the steps of preparation before construction, floor slab reinforcement, hole opening, sleeve placement, pile-forming construction and sleeve recovery.

Specifically, the scheme is as follows:

firstly, preparation of construction

1. Pile position rechecking

After receiving a pile repairing positioning drawing of a design unit, organizing related technical personnel to carry out overlapping and rechecking on the positioning drawing of the pile and an original structure drawing and check whether the condition that the pile foundation positioning collides with main stressed components such as a main beam, a column and a wall of an original structure exists or not. The pile positioning device is communicated with design negotiation aiming at the situation, pile positioning is finely adjusted within an allowable range, damage to an existing structure due to hole opening is reduced, and later-stage repairing cost is reduced.

2. Pile position location

The original structure of the floor slab and the bottom plate are perforated before pile repair, so that a three-dimensional model is constructed according to a measuring plane control net and an elevation control net, a drawing is rechecked according to the pile position, the pile position is measured by using a total station and a steel ruler, a cross pile position (shown in figure 1) is adopted as a pile bolting mark at the pile position, and a steel bar tripod is used for protection.

3. Steel sleeve model selection

The length of the steel sleeve needs to be calculated before construction, and the shortest length L required by the steel sleeve in construction is more than or equal to s + d₁+d₂+ h (where s is the depth of insertion into the soil, d₁Is the thickness of the cushion layer, d₂The thickness of the bottom plate is, and h is the depth of the basement), the depth of the steel sleeve inserted into the soil body is required to be not less than 1.0 m. The ring flange needs to be reserved at the top of the steel sleeve, if the length of the steel sleeve cannot meet the use requirement, the steel sleeve needs to be lengthened in a welded joint mode, the material requirement of the steel sleeve is Q235 steel, and the wall thickness of the sleeve is calculated according to the actual use condition.

The steel sleeve wall thickness calculation formula (5.2.1-1) is taken from GB 150.3-2011 pressure vessel: the cylinder calculation formula and the working pressure calculation in the pipe (5.2.1-2) in the P94 in the design are mainly used for considering the pressure of slurry on the side wall of a steel sleeve and the influence of construction machinery in the drilling process of a formed hole.

P＝(1+k)×ρgL (5.2.1-2)

In the formula:

t-wall thickness of steel sleeve

P-working pressure

D-outer diameter of steel sleeve

[ sigma ] -allowable stress of steel material

-weld factor, take 0.8.

C is the wall thickness addition quantity, and the value is taken according to the actual situation.

k is a construction influence coefficient, and the value range is 0-1.

Rho-mud weight

L-Steel Sleeve Length

Fourthly, floor reinforcement

And (4) rechecking the construction load of the pile machine and the design bearing capacity of a structural top plate, and reinforcing the area needing to be reinforced. The floor in the construction range of the drilling machine is reinforced by adopting the modes of full-hall supporting disc buckled steel pipe scaffold (as shown in figure 2, parameters such as transverse and longitudinal spacing, step pitch and the like are specifically set up and determined according to actual conditions), profile steel back-jacking, steel plate reinforcement and the like. In fig. 2: 1 indicates the position of the opening, 2 indicates the dish button scaffold, and 3 indicates the shaped steel.

Fifthly, drilling holes on the floor and the bottom plate

The holes on the floor and the bottom plate are drilled by a water drill, the pile point is used as a circle center O, and the hole radius R (standard query) (R ═ R) is adopted₁+r₂+50mm, where r₁Is the pile radius, r₂Radius of the water drill) is arranged, a concrete schematic diagram is shown in fig. 3, and 4 in fig. 3 refers to the water drill.

The construction key points are as follows:

1) the opening construction is carried out by ensuring the concentricity and the same diameter of the upper opening, the middle opening and the lower opening of the same pile position;

2) if a large verticality deviation occurs in the drilling process of the water drilling, stopping drilling, and using a sleeve with a large aperture to drill again to ensure that the verticality meets the construction requirement;

3) after the hole of each layer plate is opened, a model steel sleeve with the length of 1m and the same diameter as that of the long sleeve to be installed is adopted for trial installation, whether the phenomenon of sticking exists between the wall of the sleeve and the edge of the plate is observed, and if the problem exists, the hole is repaired again to ensure the smooth installation of the subsequent long sleeve;

4) after the upper, middle and lower three-layer plates are all perforated, a pile position control point of a cross bolt pile position is utilized, and a line weight and a steel ruler are adopted to check the concentricity.

Sixthly, placing the steel sleeve

1. Hoisting of steel sleeve

A50T truck crane is used for carrying out two-point hoisting, the steel sleeve is erected and then changed into single-head hoisting, the lifting lugs are made of Q235 steel plates with the thickness of 25mm, the size of each connecting plate is 20cm in the vertical direction, 15cm in the circumferential direction, the size of each lug plate is 20cm in the radial direction, 10cm in the circumferential direction (lug width) and the aperture is 5 cm. The lug is cut off before the sleeve returns the straight installation, avoids influencing the sleeve and transfers, demolishs top and section portion interior support.

The depth of the sleeve entering undisturbed soil below the bottom plate is not less than 1m, a hydraulic vibration hammer is adopted to finish the sinking construction of the steel sleeve, a preset position is marked on the sleeve by paint before sinking, the steel sleeve stops when in place, and the subsequent reinforcement measures are finished. Adopt the reinforcing bar to fix with the welding of well style of calligraphy on each layer of concrete face after the sleeve installation is accomplished, prevent among the pore-forming process that the pile casing landing, translation.

2. Sealing treatment between steel sleeve and bottom plate

After the steel sleeve is hoisted in place, an annular water stop ring (with the width of 100mm and the thickness of 3mm) is welded at the joint of the steel sleeve and the bottom plate, and a concrete pier is poured (the actual construction size is determined by calculation of a formula 5.2.5-1), as shown in fig. 4. In fig. 4: 5 indicate steel sleeve, 6 indicate seal ring, 7 indicate the bottom plate, 8 indicate the concrete, the computational formula that relates to is as follows:

wherein:

v-concrete pier volume

ρ₁Is the specific gravity of the slurry; rho₂The volume weight of the soil under the bottom plate; rho₃Is the density of concrete

L-Steel Sleeve Length

S-depth of sleeve into soil

A-clearance between the bottom plate and the steel sleeve, can be approximately as follows

Calculating, wherein R is the radius of the opening and D is the outer diameter of the steel sleeve

Sixthly, pile forming and subsequent construction

Compared with the conventional cast-in-situ bored pile construction, the pile forming construction is characterized in that a pile machine is positioned on a top plate of a basement for pile filling construction, and pile forming verticality is a control point of the construction, so that the verticality of a drill bit and a drill rod during construction is focused. In the drilling process of the pile machine, the pile perpendicularity is measured once every 5 meters of forward movement, and the pile perpendicularity is rechecked after the pile is completed, so that the pile perpendicularity can meet the use requirement.

And (3) splitting the grouting pipe by clear water within 7-8 hours after the pile is formed, so that the grouting pipe is kept smooth. Grouting should be carried out 2 days after pile formation. Grouting should be kept at low pressure and slow speed. The grouting should adopt P.042.5-grade cement slurry, and the water-cement ratio is controlled to be 0.55-0.6. The grouting amount of the engineering pile is adjusted correspondingly according to the static load test result. The grouting amount is used as the main control, and the grouting pressure is used as the auxiliary control. The grouting termination meets the following conditions:

1) the grouting amount meets the design requirement;

2) the grouting amount is not less than 80% of the design requirement, and the pressure is not less than 2 MPa.

3) And carrying out ultrasonic detection on the pile body 28 days after the concrete pouring is finished.

Seven, retrieve sleeve

And (3) removing reinforcing steel bars of the sleeve at each floor position after the concrete pouring is finished for about 4-5 hours (after the concrete is initially set) after the pile repairing construction, chiseling a concrete pier sealed by the steel sleeve and the bottom plate, and cutting off a water stop ring. And (4) pulling out the steel sleeve by adopting a hydraulic vibration hammer, and directly hanging the pulled-out steel sleeve to a next hole site for installation. The basement adopts LED lamp area to provide the illumination in this embodiment.

The materials and equipment involved in this example are shown in tables 1 and 2, respectively.

TABLE 1 materials usage table

TABLE 2 Equipment usage table

The construction method disclosed by the embodiment has the following advantages:

(1) the floor is perforated by a water drill, so that noise pollution and dust pollution are reduced;

(2) the basement adopts the LED lamp strip to provide illumination, so that the energy consumption is reduced;

(3) the sleeve is used for drainage, so that the pollution of slurry to the existing basement structure in the traditional pile-repairing construction is avoided;

(4) the slurry generated by pile repair construction is treated by a mud-water separation system and then delivered out of a factory, so that the treatment efficiency is improved, and the pollution to the environment is reduced;

(5) the generated construction waste is less, and the construction waste is treated in a centralized clearing mode, so that the tidiness of a construction site is ensured;

(6) continuous precipitation is avoided, underground water resources are protected, and meanwhile, the influence on the surrounding environment is reduced.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims (10)

1. A high water level existing basement pile foundation construction method is characterized by sequentially comprising the following steps: the method comprises the steps of preparation before construction, floor slab reinforcement, hole opening, sleeve placement, pile-forming construction and sleeve recovery.

2. The construction method according to claim 1, wherein the pre-construction preparation step comprises: pile position rechecking, pile position positioning and sleeve type selection.

3. The method of claim 2, wherein the pile position locating method comprises: and (3) checking the drawing according to the pile position, measuring the pile position by using a total station and a steel ruler, marking the pile position by adopting a cross pile-bolting method, and protecting.

4. The method of claim 2, wherein the sleeve sizing step comprises: the length of the sleeve is calculated before construction, and the shortest length L required by the sleeve in construction is more than or equal to s + d₁+d₂+ h, where s is the depth of insertion into the soil, d₁Is the thickness of the cushion layer, d₂The thickness of the bottom plate is, h is the depth of the basement, and the depth of the sleeve inserted into the soil body is required to be not less than 1.0 m.

5. The method of claim 1, wherein the sleeve is a steel sleeve.

6. The method of claim 1, wherein the floor slab reinforcing step comprises: rechecking the construction load of the pile machine and the design bearing capacity of a structural top plate, and reinforcing the area needing to be reinforced; preferably, the floor in the construction range of the drilling machine is reinforced by adopting a disc buckle type scaffold, a profile steel return top and a steel plate reinforcing mode.

7. The method of claim 1, wherein the step of aperturing comprises: and (3) drilling holes on the floor slab and the bottom plate, constructing by using water drilling holes, and arranging a plurality of water drilling holes in a circle by taking the pile site as the circle center.

8. The method of claim 1, wherein the sleeve placing step comprises: the sleeve is erected and then inserted into the lower layer of the bottom plate in a hoisting mode, the sleeve sinking construction is completed by adopting a hydraulic vibration hammer, a preset position is marked on the sleeve by using paint before sinking, the sleeve stops when in place, and then water stopping treatment is carried out.

9. The method of claim 8, wherein the water stop treatment step comprises: and an annular water stop ring is welded at the joint of the sleeve and the bottom plate.

10. The method of claim 1, wherein the piling constructing step comprises: in the drilling process of the pile machine, measuring the pile perpendicularity every 5 meters, and rechecking the pile perpendicularity after the pile is completed;

clear water is used for splitting the grouting pipe within 7-8 hours after the pile is formed, so that the grouting pipe is kept smooth; grouting is carried out after the pile is formed for 1.5 to 2.5 days.

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