Construction method for manually excavating support pile

Abstract

The invention provides a construction method for manually excavating a support pile, which comprises the following steps of: leveling a site of a construction area, carrying out survey and lofting, carrying out fore shaft construction at a preset position, excavating a first section of pile hole and constructing a retaining wall, erecting a template in the excavated retaining wall and pouring concrete, excavating a lower section of pile hole, and binding reinforcing steel bars of the retaining wall. The inner wall of the pile hole and the bottom of the pile hole are subjected to coring through a water milling drill, finally excavation is conducted to the designed depth, pile body steel bars are bound, pile body concrete is poured, and pile body detection is conducted after the pile body concrete reaches the designed strength; the problem that in the prior art, if supporting measures are not in place in the construction process, hole wall collapse or pile hole instability is prone to occurring, and therefore the overall quality of a pile hole is affected is solved.

Description

Technical Field

[0001] The invention relates to the technical field of pile foundation hole construction, and in particular to a construction method of artificially excavated support piles. Background Art

[0002] Manually dug pile holes are a common foundation treatment method and are widely used in foundation construction in construction projects. Pile foundations have good bearing capacity and earthquake resistance, and can effectively disperse the load of buildings to deep soil or bedrock. They are particularly suitable for foundations with poor bearing capacity. When the construction site is narrow, mechanical equipment cannot enter, or complex geological conditions are encountered, manually dug pile holes can deal with these problems more flexibly. In addition, the construction equipment for manually dug pile holes is simple, and the required site space is small, which is suitable for special construction environments such as densely populated urban areas and complex underground pipelines.

[0003] At present, in the process of artificial pile hole construction, the support and wall protection quality of the pile hole directly affects the bearing capacity and stability of the pile foundation. If the support measures are not in place during the construction process, it is very easy for the hole wall to collapse or the pile hole to become unstable, thus affecting the overall quality of the pile hole. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a method for constructing manually excavated support piles, which solves the problem in the prior art that if the support measures are not in place during the construction process, the hole wall collapse or the pile hole instability may easily occur, thereby affecting the overall quality of the pile hole.

[0005] According to an embodiment of the present invention, a method for constructing manually excavated supporting piles comprises the following steps: leveling the construction area site, measuring and setting out, performing locking construction at a predetermined position, excavating the first section of the pile hole and constructing a retaining wall, supporting a formwork in the excavated retaining wall and pouring concrete, excavating the lower section of the pile hole, tying the retaining wall reinforcement, pulling and connecting the reinforcement in the lower section with the reinforcement in the upper section, coring the inner wall of the pile hole and the bottom of the pile hole with a water-grinding drill, and finally excavating to the designed depth, tying the pile body reinforcement, pouring the pile body concrete, and inspecting the pile body after the pile body concrete reaches the designed strength.

[0006] Compared with the prior art, the present invention has the following beneficial effects: after applying a lock mouth in the area to be excavated, excavation is carried out in sections downwards; after excavating the first section of the pile hole, a retaining wall is applied on the inner wall of the pile hole; a template is supported on the excavated pile hole and concrete is poured; after the concrete reaches the designed strength, the next section of the pile hole is excavated; when the retaining wall steel bars of the next section of the pile hole are tied, the retaining wall steel bars in the lower section are connected with the steel bars in the upper section; a water-grinding drill is used to core the inner wall of the pile hole and the bottom of the pile hole to the designed depth; finally, the pile body steel bars are lowered and the pile body concrete is poured to form a pile; since the construction method excavates in sections and connects the retaining wall steel bars in the lower section with the retaining wall steel bars in the upper section, settlement or displacement of the retaining wall steel bars in the upper section is avoided when the lower section of the pile hole is excavated, thereby ensuring the stability of the retaining wall, effectively avoiding the hole wall collapse or pile hole instability caused by inadequate support measures, and thus improving the overall quality of the pile hole.

[0007] Furthermore, the soft soil in the pile hole is replaced during the excavation process of the pile hole.

[0008] Further, after leveling the site, drainage ditches are arranged around the pile holes to be excavated.

[0009] Furthermore, if the wall reinforcement or pile reinforcement does not meet the acceptance conditions after being tied, it needs to be re-tied.

[0010] Furthermore, a temporary sump is provided in the pile hole during the excavation process.

[0011] Furthermore, skip hole excavation is implemented when excavating multiple pile holes.

[0012] Furthermore, the concrete is poured in layers.

[0013] Furthermore, when tying the wall reinforcement, anchor rods are arranged radially in the pile hole.

[0014] Furthermore, a winch is installed after the first section of the retaining wall is excavated. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a flow chart of an embodiment of the present invention.

[0016] Figure 2 It is a schematic diagram of coring by a water-grinding drill according to an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0018] like Figure 1—2, an embodiment of the present invention proposes a method for constructing manually excavated supporting piles, comprising the following steps: leveling the construction area, measuring and setting out, performing locking construction at a predetermined position, excavating the first section of the pile hole and constructing a retaining wall, supporting a formwork in the excavated retaining wall and pouring concrete, excavating the lower section of the pile hole, tying the retaining wall steel bars, connecting the steel bars in the lower section with the steel bars in the upper section, coring the inner wall of the pile hole and the bottom of the pile hole with a water-grinding drill, and finally excavating to a designed depth, tying the pile body steel bars, pouring the pile body concrete, and inspecting the pile body after the pile body concrete reaches the designed strength. When the site is leveled, a backhoe is used to remove surface debris, vegetation, construction waste, etc. and transport them to the designated abandoned soil site. A construction platform with a width of not less than 2M is leveled. The height of the excavation and backfilling of the construction platform is determined by measurement and setting out. An excavator is used for excavation and backfilling. Drainage ditches are set on the stone columns of the pile holes to prevent surface water from entering the pile holes and causing pile collapse. At the same time, it provides convenience for the subsequent discharge of water seepage in the pile holes. The top of the pile hole lock should be 20CM higher than the ground. Before pouring concrete on the pile hole lock, the steel bars of the protective railings and the steering crane are embedded. After pouring concrete, the steering hanger is installed after the concrete strength of the pile hole lock reaches 75%. The steering hanger is fixed to the lock with counterweights and steel hoops. The jumping pile method is used for excavation of multiple pile holes. When the depth of the pile hole exceeds two meters, a blower and an air duct are used to transport air into the pile hole. After the depth of the pile hole exceeds 5M, the air supply of the blower is increased and continuous ventilation is carried out. The excavation is carried out manually with a pneumatic pick from top to bottom in sections. Generally, the construction section is about 1M, and the easily collapsed stratum is 0.3-0.5M as a section. When excavating in the same section, the periphery is first excavated and then the middle. The templates of the lock and the retaining wall are assembled bamboo plywood templates. To ensure the accuracy of the template and the verticality of the pile hole, a plumb ball is used to drop from the lock to the excavation surface for inspection. After confirming that the template is installed correctly, concrete can be poured. The concrete strength grade is C30, and it is vibrated with an inserted vibrator. When pouring concrete, the concrete is poured evenly to avoid bias pressure causing the overall offset of the template. After the first section of the retaining wall is poured, the axes and control elevations are led to the upper mouth of the retaining wall, and the standard axes are nailed with small iron nails and marked with red paint to facilitate the control of the pile elevation and center. The pre-processed steel bars are hoisted into the pile hole, and the vertical steel bars and the steel bars in the upper section of the retaining wall are overlapped or pulled together with the vertical steel bars in the lower section of the retaining wall to avoid the settlement or displacement of the retaining wall steel bars in the upper section when the lower section of the pile hole is excavated. After the pile hole is excavated to the designed depth, the loose slag, floating soil, retaining wall sludge, silt, sediment and other disturbed soft layers at the bottom of the pile hole are cleaned up. After a section of the pile hole is excavated and the concrete of the retaining wall reaches the designed strength, the next section of the pile hole is excavated downward.Specifically, during the water-grinding drilling construction, several coring points are set at equal intervals along the circumferential direction of the pile hole, and the cores are drilled based on the coring points. After the cores are taken, a circular free surface is formed on the inner wall of the pile hole. Multiple cores are drilled based on the bottom of the pile hole, and then a steel wedge is inserted. By hitting the steel wedge, the rock at the bottom of the pile hole receives a horizontal impact force. Under the action of the horizontal impact force, the rock in the pile hole is cracked along the plumb plane, and horizontal shear failure occurs at the bottom of the pile hole. The slag is hoisted out of the pile hole by a winch, and the steel bars are tied and formed in the pile hole. Specifically, the steel bars are processed in a steel bar processing plant before construction. The transport vehicle transports the steel bars to the site, and the crane and manual labor are used to hoist the single main steel bar into the pile hole and install it at the designed position, and fix it with stirrups. After all the main bars are installed in this way, all the remaining steel bars are tied. The pile body concrete uses commercial concrete and is transported by concrete tank trucks. Before pouring, the pile hole wall and the bottom of the pile hole are cleaned to ensure that there is no sediment at the bottom of the pile hole, and the water in the pile hole is drained with submersible pumps and other equipment. The small amount of water remaining at the bottom of the pile hole must be drained with an iron ladle and sponge, and then concrete is poured through the string tube. The height of the end of the string tube from the bottom of the hole and the concrete surface shall not exceed two meters. Before pouring concrete, the hole diameter, hole depth, and hole shape should be fully inspected and reported to the supervision engineer. Concrete pouring can only be carried out after passing the inspection. At the pile-sheet wall positions on both sides of the pile body, pile-sheet wall steel bars are embedded, and the steel bars extending out of the pile body are bent to 90 degrees, close to the retaining wall, so as to facilitate the later chiseling of the embedded steel bars. Generally, the inspection is carried out after the concrete strength of the pile body reaches 75%. Before pouring the pile body concrete, a detection tube is embedded in the pile to be inspected. In this embodiment, the detection tube is an acoustic detection tube. In order to fix the acoustic detection tube, tension bars (Φ14@500, three lines, arranged vertically along the pile) are added in the pile to fix the acoustic detection tube so that they are parallel to each other after the pile is formed, and the acoustic detection tubes are arranged in a symmetrical shape along the outer side of the pile cross section.

[0019] Furthermore, the soft soil in the pile hole is replaced during the excavation of the pile hole. During the excavation of the pile hole, a soft soil layer (such as silt, quicksand, etc.) is encountered. The low strength and high compressibility of the soft soil may cause the hole wall to be unstable and the bearing capacity to be insufficient. At this time, the soft soil is removed manually or mechanically, and the appropriate graded materials are filled into the pile hole, and the filling and compaction are carried out layer by layer, so as to ensure the strength of the inner wall of the pile hole in the later stage.

[0020] Furthermore, after the site is leveled, drainage ditches are set around the pile holes to be excavated. The drainage ditches prevent surface water from entering the pile holes and causing the pile holes to collapse.

[0021] like Figure 1 As shown, further, if the wall reinforcement or pile reinforcement does not meet the acceptance conditions after being tied, it is necessary to re-tie. After the wall reinforcement or pile reinforcement is tied, it is necessary to ensure the appropriate spacing and tie it firmly. The reinforcement that does not meet the requirements shall be removed, and the stability of the constructed part shall be minimized during the removal.

[0022] Furthermore, a temporary water collection pit is set up in the pile hole during the excavation process. During the excavation process, if groundwater is affected, a temporary water collection pit is dug in the pile hole, and a high-lift submersible pump is used to pump water while excavating. A special person is sent to the ground to repair the drainage ditch and drain the water pumped out of the pile hole in time.

[0023] Furthermore, when excavating multiple pile holes, skipping hole excavation is implemented. By skipping hole excavation, while improving construction efficiency, some pile holes are skipped in order, and the alternate pile holes are excavated first, and then the remaining pile holes are excavated. Especially when excavating pile holes in areas with a lot of soft soil or high groundwater levels, the occurrence of hole collapse and instability of retaining walls can be effectively avoided.

[0024] Furthermore, the concrete is poured in layers. Specifically, in this embodiment, the thickness of each layer is 30-45CM, and the concrete is vibrated by an inserted vibrator. The method of fast insertion and slow withdrawal is adopted during the vibration, and the vibrating rod is continuously moved up and down to vibrate evenly. The moving spacing of the inserted vibrator should not be greater than 1.5 times its effective radius, that is, it should not be greater than 37.5CM. The vibrating rod is inserted into the concrete for 5-10CM and keeps a distance of 5-10CM from the side wall of the pile hole. For each vibrated part, vibrate until the part is dense, that is, the concrete no longer sinks significantly, no bubbles appear, and the slurry begins to overflow. During the pouring process, the top surface of the concrete shall not accumulate more than 5CM of water, and the accumulated water must be removed before pouring can continue. After the concrete is poured to the designed pile top elevation, cover the pile top with water-retaining materials and sprinkle water for curing, or backfill and bury the pile for water-retaining curing. When covering and sprinkling with water-retaining materials for curing, sprinkle water several times a day to keep the concrete surface moist. The concrete curing age shall be no less than 14 days.

[0025] Furthermore, when tying the retaining wall reinforcement, anchor rods are arranged radially in the pile hole. When necessary, anchor rods can be arranged radially in the pile hole to prevent the upper retaining wall reinforcement from settling or deflecting when the next pile hole is excavated.

[0026] like Figure 1 As shown, further, after the first section of the retaining wall is excavated, a winch is installed. Specifically, the winch is an electric winch, which is installed directly above the pile hole through a lifting frame, and a bucket is suspended on the winch, which is lowered into the pile hole through the bucket, so that workers can shovel the excavated mud into the bucket and discharge the mud in the pile hole to the outside.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A construction method of manually excavated support piles, characterized in that: The following steps are involved: Level the construction area and conduct survey and layout; Carry out lock construction at the predetermined location; Dig the first pile hole and construct retaining wall; Set up formwork and pour concrete inside the excavated retaining wall; Excavation of the lower pile hole; Tie the wall reinforcement bars, and connect the reinforcement bars at the lower section with the reinforcement bars at the upper section; The water-grinding drill cores the inner wall and bottom of the pile hole and finally excavates to the designed depth; Pile reinforcement binding; Pouring pile concrete; The pile body is inspected after the pile body concrete reaches the design strength.

2. A method for constructing artificial excavated support piles as claimed in claim 1, characterized in that: During the excavation of the pile hole, the soft soil in the pile hole is replaced.

3. A method for constructing artificial excavated support piles as claimed in claim 1, characterized in that: After leveling the site, drainage ditches are set up around the pile holes to be excavated.

4. A method for constructing artificial excavated support piles as claimed in claim 1, characterized in that: If the wall reinforcement or pile body reinforcement does not meet the acceptance conditions after being tied, it shall be re-tied.

5. The method for constructing artificial excavated support piles according to claim 1, characterized in that: During the excavation process, a temporary sump is set up in the pile hole.

6. The method for constructing artificial excavated support piles according to claim 1, characterized in that: When excavating multiple pile holes, skip hole excavation is implemented.

7. The method for constructing artificial excavated support piles according to claim 1, characterized in that: When pouring concrete, pour it in layers.

8. The method for constructing artificial excavated support piles according to claim 1, characterized in that: When tying the wall reinforcement, anchor rods are arranged radially in the pile hole.

9. The method for constructing artificial excavated support piles according to claim 1, characterized in that: After excavating the first section of retaining wall, install the winch.

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