A protection system and construction method for the pile head of cast-in-place piles in a complex construction environment

Abstract

The present invention provides a protection system and construction method for the pile head of a cast-in-place pile under complex construction environments. The pile head protection system includes a front-section protection unit, a middle-section protection unit, and a rear-section protection unit. A pile hole is formed inside a building foundation pit. The bottom of the building foundation pit is the foundation soil layer, and the top is the soil layer between piles. A cast-in-place pile is poured in the pile hole. The exposed part at the top of the cast-in-place pile is the pile head main body, and the bottom of the pile head main body is the pile head foundation. The pile head foundation extends outward upward with a circularly arrayed bearing platform steel bars. The inner side of the bearing platform steel bars is the inner steel pile body, and the outer side is the outer steel pile body. By arranging protection units at the front, middle, and rear, the present invention can achieve full-process protection of the pile head, ensure the construction efficiency and quality of the pile head. The structures of the three-section protection units are interconnected and interdependent, making the entire construction process more continuous and simplifying the protection steps.

Description

Technical Field

[0001] The present invention relates to the technical field of cast-in-place pile construction, and specifically relates to a protection system and construction method for the pile head of a cast-in-place pile under a complex construction environment. Background Art

[0002] Cast-in-place pile construction refers to forming a pile hole in the foundation soil at the construction site by means of mechanical drilling, steel pipe soil extrusion or manual excavation, etc., and placing a steel reinforcement cage and pouring concrete therein to form a pile;

[0003] After the cast-in-place pile is constructed, the pile head needs to be processed, and the processing steps are as follows: clean the soil between the piles to expose the pile head part, then break the outer pile body and inner pile body of the steel bars of the pile head, and only retain the bearing platform steel bars and the pile head foundation. Finally, lay a waterproof layer to protect the pile head foundation;

[0004] However, the protection measures for the pile head are limited. Only a waterproof layer is laid to protect the pile head foundation. However, the pile head construction environment is complex and the construction steps are cumbersome. The pile head is easily damaged in the following situations:

[0005] 1. When cleaning the soil between the piles, the bucket of the excavator often knocks against the pile head, resulting in the inclination or fracture of the pile head, which is very troublesome in the subsequent separation process and affects the forming quality of the pile head foundation;

[0006] 2. When lifting the inner pile body of the steel bar, the inner pile body of the steel bar deflects due to the deviation of the center of gravity, and then presses down on the bearing platform steel bar, making the bearing platform steel bar easily bend and be damaged or even broken.

[0007] In summary, there is a need for a protection system that can play a protective effect in each construction stage of the pile head. Summary of the Invention

[0008] Aiming at the deficiencies of the prior art, the present invention provides a protection system for the pile head of a cast-in-place pile under a complex construction environment, and solves the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention is realized through the following technical solutions:

[0010] A protection system for the pile head of a cast-in-place pile under a complex construction environment. The pile head protection system includes a front-section protection unit, a middle-section protection unit, and a rear-section protection unit. A pile hole is opened inside a building foundation pit. The bottom of the building foundation pit is a foundation soil layer, and the top is a soil layer between piles. A cast-in-place pile is poured in the pile hole. The exposed part at the top of the cast-in-place pile is the pile head main body. The bottom of the pile head main body is the pile head foundation. The pile head foundation extends upward with a circular-array-distributed bearing platform steel bar. The inner side of the bearing platform steel bar is the inner pile body of the steel bar, and the outer side is the outer pile body of the steel bar;

[0011] The front protection unit is arranged during the formation of the cast-in-place pile and the cleaning of the soil between the piles; the front protection unit includes an upper tube body and a lower tube body, and the pile head body is formed in the upper tube body and the lower tube body; the upper tube body stopper is embedded in the inner top of the pile hole, and the lower tube body is detachably installed flush with the bottom end of the upper tube body; the upper tube body and the lower tube body assembled as one are used to shape and protect the pile head body during the pouring stage and the cleaning of the soil between the piles stage;

[0012] The middle section protection unit is arranged during the removal stage of the inner and outer reinforcement pile bodies; the middle section protection unit includes a lower pipe body, which is used to protect the pile head foundation;

[0013] The rear protection unit is arranged after the pile head is broken; the rear protection unit includes a waterproof component, a steel protection cover and a lower pipe body. The waterproof component is laid on the pile head foundation, the lower pipe body and the surface of the foundation soil layer, and the steel protection cover covers the outside of the foundation steel bars.

[0014] Furthermore, an upper ring groove is provided on the surface of the lower tube body, and a plurality of second screw holes are provided at positions of the outer wall of the lower tube body relative to the upper ring groove. Locking screws pass through the second screw holes, and the second screw holes are vertically connected to the upper ring groove. A side ring groove is provided on the outer wall of the lower tube body.

[0015] Furthermore, the top end of the upper tube body is bent outward to form a retaining ring, which stops on the surface of the soil layer between the piles. A plurality of first screw holes are provided on the surface of the retaining ring, and the first screw holes are connected to the first lifting ring or the pouring support assembly. The bottom end of the upper tube body is provided with an insert ring that cooperates with the upper ring groove, and the insert ring is fixed to the lower tube body by a locking screw.

[0016] Furthermore, the cast-in-place support assembly includes a side frame body and a steel cage guide ring. The two side frames are symmetrically installed on the retaining ring. A steel cage guide ring is provided between the two side frames. The steel cage guide ring is used to guide and constrain the installation process of the steel cage. A pre-embedded lifting assembly is installed on the bottom surface of the steel cage guide ring, and the bottom end of the pre-embedded lifting assembly is pre-embedded in the pile body of the steel bar.

[0017] Furthermore, the embedded lifting assembly includes a connecting ring plate, a sleeve, and an anchor rod; a plurality of sleeves are vertically arranged on the bottom surface of the connecting ring plate, an anchor rod is inserted inside each sleeve, an assembly hole is opened at the top end of the anchor rod, and a barb is opened on the outer wall of the bottom end; the anchor rod is embedded in the pile body of the steel bar, and a third screw hole is opened on the surface of the connecting ring plate, and the third screw hole cooperates with the connecting steel bar cage guide ring or the second lifting ring.

[0018] Further, the waterproof component includes a waterproof expansion rubber sleeve, a concrete cushion layer, a cementitious capillary crystalline waterproof coating, a polymer cement waterproof layer, a coiled material waterproof layer, and a fine aggregate concrete layer; a waterproof expansion rubber sleeve is sleeved on the root of the pile cap steel bars, the concrete cushion layer is circularly laid on the foundation soil layer, and the cementitious capillary crystalline waterproof coating is laid on the surfaces of the concrete cushion layer, the lower pipe body, and the pile foundation. The coiled material waterproof layer is laid on the surface of the cementitious capillary crystalline waterproof coating, and the coiled material waterproof layer is pressed into the upper ring groove through a first pressing ring and into the side ring groove through a second pressing ring. A fine aggregate concrete layer is laid on the surface of the coiled material waterproof layer.

[0019] Further, the steel bar protection cover includes a main frame, expansion columns, a guiding frame, and a clamping assembly. The main frame includes a first plate body and a first support plate. Four annularly arranged first support plates are provided on the bottom surface of the first plate body. A clamping assembly vertically penetrates through the bottom end of each first support plate. The inner ends of the four clamping assemblies clamp the outer wall of the fine aggregate concrete layer. A perforation is provided at the center of the first plate body. The guiding frame includes an annular cover and a second support plate. The second support plate is vertically arranged on the surface of the first plate body and symmetrically arranged on both sides of the perforation. An annular cover is provided at the top end of the second support plate. The expansion column includes a tapered column and a second plate body. The second plate body is provided at the top end of the tapered column. The second plate body is vertically slidably connected to the annular cover and the second support plate. The second plate body is abutted against the surface of the first plate body. The maximum outer diameter of the tapered column is the same as the inner diameter of the perforation. The downward moving tapered column synchronously expands each pile cap steel bar outwards.

[0020] The construction method of the pile head protection system for cast-in-place piles in a complex construction environment. The construction method includes the following steps:

[0021] S1. Protection of the front section of the pile head:

[0022] Install an assembled protection component at the inner top of the pile hole. The upper pipe body of the protection component is erected on the surface of the soil layer between piles.

[0023] Install the pouring support component and the embedded lifting component on the surface of the upper pipe body.

[0024] Pass the steel reinforcement cage through the pouring support component and put it into the pile hole.

[0025] Pour concrete into the pile hole. The pile head is formed inside the upper pipe body and the lower pipe body to obtain a cast-in-place pile. The bottom end of the embedded lifting component is embedded into the steel bar inner pile body.

[0026] S2. Protection of the middle section of the pile head:

[0027] Dismantle the pouring support component.

[0028] Clean the soil between piles. During the cleaning process, the upper pipe body and the lower pipe body protect the pile head to avoid accidental damage to the pile head.

[0029] Unscrew the locking screw at the connection of the upper pipe body and the lower pipe body, install the first lifting ring on the upper pipe body, and then lift the upper pipe body to expose the upper part of the pile body main body;

[0030] Workers break the outer pile body of the reinforcement along the top surface of the lower pipe body, chisel through the root of the inner pile body of the reinforcement, and then install the second lifting ring on the embedded lifting component to lift the inner pile body of the reinforcement, and the lower pipe body always protects the pile head foundation;

[0031] S3. Protection of the latter-stage pile head:

[0032] Lay a waterproof component on the surfaces of the pile head foundation and the foundation soil layer;

[0033] Install the main frame outside the pile head foundation, adjust each clamping component so that the clamping component is clamped and positioned outside the pile head foundation, and vertically hammer the expansion column into each pile cap reinforcement along the guiding frame. The expansion column synchronously drives each pile cap reinforcement to bend outward by 70°; in this way, the main frame and the expansion column can protect the bent pile cap reinforcement.

[0034] The present invention provides a protection system for the pile head of a cast-in-place pile in a complex construction environment. Compared with the prior art, it has the following beneficial effects:

[0035] By arranging protection units in the front, middle, and rear stages, full-process protection of the pile head can be achieved, ensuring the construction efficiency and construction quality of the pile head. The structures of the three-stage protection units are interconnected and interdependent, making the entire construction process more continuous and simplifying the protection steps. Description of the Drawings

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0037] Figure 1 Shows the structural schematic diagram of the front-stage protection unit in the pouring stage of the present invention;

[0038] Figure 2 Shows the structural schematic diagram of the front-stage protection unit in the cleaning stage of the soil between piles of the present invention;

[0039] Figure 3 Shows the structural schematic diagram of the protection component of the present invention;

[0040] Figure 4 Shows the structural schematic diagram of the anchor rod of the present invention;

[0041] Figure 5Shows the schematic diagram of the connection structure of the upper pipe body and the lower pipe body of the present invention;

[0042] Figure 6 Shows the schematic diagram of the structure of the middle section protection unit of the present invention;

[0043] Figure 7 Shows the schematic diagram of the structure of the rear section protection unit of the present invention;

[0044] Figure 8 Shows Figure 7 The enlarged schematic diagram of the structure at position A of

[0045] Figure 9 Shows the schematic diagram of the structure of the steel bar protection cover of the present invention;

[0046] Figure 10 Shows the cross-sectional schematic diagram of the steel bar protection cover of the present invention;

[0047] As shown in the figure: 1. Building foundation pit; 11. Foundation soil layer; 12. Soil layer between piles; 13. Pile hole; 2. Protection component; 21. Upper pipe body; 211. Retaining ring; 2111. First screw hole; 212. Inserting ring; 22. Lower pipe body; 221. Upper ring groove; 222. Side ring groove; 223. Second screw hole; 23. First lifting ring; 24. Locking screw; 3. Grouting support component; 31. Side frame body; 32. Steel reinforcement cage guiding ring; 4. Embedded lifting component; 41. Connecting ring plate; 411. Third screw hole; 42. Sleeve; 43. Anchor rod; 431. Barbs; 432. Assembly hole; 44. Second lifting ring; 5. Cast-in-place pile; 51. Pile head main body; 511. Pile head foundation; 512. Inner steel bar pile body; 513. Outer steel bar pile body; 6. Cap steel reinforcement; 7. Waterproof expansion rubber sleeve; 8. Steel bar protection cover; 81. Main frame; 811. First plate body; 812. First support plate; 82. Expansion column; 821. Taper column; 822. Second plate body; 8221. Slide block; 83. Guide frame; 831. Ring cover; 8311. Vertical groove; 832. Second support plate; 84. Clamping component; 841. Adjusting screw; 842. Pressing plate; 9. Concrete cushion; 9a. Cementitious capillary crystalline waterproof coating; 9b. Polymer cement waterproof layer; 9c. Coiled material waterproof layer; 9d. Fine aggregate concrete layer; 9e. First pressing ring; 9f. Second pressing ring. Detailed implementation manners

[0048] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0049] Example 1

[0050] To solve the technical problems in the background art, the following cast-in-place pile head protection system in a complex construction environment is provided:

[0051] Combined with Figures 1 - 10 As shown in the figure, for the cast-in-place pile head protection system in a complex construction environment provided by the present invention, the pile head protection system includes a front section protection unit, a middle section protection unit, and a rear section protection unit. A pile hole 13 is provided inside a building foundation pit 1. The bottom of the building foundation pit 1 is a foundation soil layer 11, and the top is an inter-pile soil layer 12. A cast-in-place pile 5 is poured in the pile hole 13. The exposed part at the top of the cast-in-place pile 5 is the pile head main body 51. The bottom of the pile head main body 51 is the pile head foundation 511. The pile head foundation 511 extends outward upward with a ring-arrayed bearing platform steel bars 6. The inner side of the bearing platform steel bars 6 is the steel bar inner pile body 512, and the outer side is the steel bar outer pile body 513;

[0052] The front section protection unit is arranged during the formation of the cast-in-place pile 5 and the cleaning of the inter-pile soil. The front section protection unit includes an upper pipe body 21 and a lower pipe body 22. The pile head main body 51 is formed inside the upper pipe body 21 and the lower pipe body 22. The upper pipe body 21 is stopped and embedded in the inner top of the pile hole 13, and the lower pipe body 22 is detachably installed at the bottom end of the upper pipe body 21 in a flush manner. The assembled upper pipe body 21 and lower pipe body 22 are used to perform shaping protection on the pile head main body 51 during the pouring stage and the cleaning of the inter-pile soil stage. The middle section protection unit is arranged during the breaking of the steel bar inner pile body 512 and the steel bar outer pile body 513. The middle section protection unit includes the lower pipe body 22, and the lower pipe body 22 is used to protect the pile head foundation 511. The rear section protection unit is arranged after the pile head is broken. The rear section protection unit includes a waterproof component, a steel bar protection cover 8, and the lower pipe body 22. The waterproof component is laid on the surfaces of the pile head foundation 511, the lower pipe body 22, and the foundation soil layer 11, and the steel bar protection cover 8 covers the outside of the bearing platform steel bars 6.

[0053] By arranging protection units in the front, middle, and rear, this system can achieve full-process protection of the pile head, ensure the construction efficiency and quality of the pile head. The structures of the three-section protection units are interconnected and interdependent, making the entire construction process more continuous and simplifying the protection steps;

[0054] In the front section protection unit, the upper pipe body 21 and the lower pipe body 22 can be used to enclose and protect the top of the pile hole 13. On the one hand, it ensures the solidification of the soil quality at the top of the pile hole 13 during the pouring and forming process and avoids the collapse of the hole top. On the other hand, the upper pipe body 21 and the lower pipe body 22 are preset outside the pile head at this step, which is convenient for avoiding the damage of the bucket of the excavator to the pile head during the subsequent cleaning of the inter-pile soil process, ensuring the integrity of the pile head, and facilitating subsequent professional demolition and pile body detection;

[0055] In the middle-section protection unit, the remaining lower pipe body 22 can serve as a cutting mark, and the worker can just perform the breaking operation along the top surface of the upper pipe body 21. In this way, the operation of the worker is made more convenient, and the height of the pile head foundation 511 is ensured. At the same time, during the demolition process, due to the positioning constraint of the lower pipe body 22 on the pile head foundation 511, the integrity of the pile head foundation 511 is ensured.

[0056] In the rear-section protection unit, in order to ensure the waterproof ability of the bent steel bars and the pile head foundation 511, a waterproof component and a steel bar protection cover 8 are arranged.

[0057] As an improvement of the above technical solution, an upper ring groove 221 is formed on the surface of the lower pipe body 22. A plurality of second screw holes 223 are formed at the relative position between the outer wall of the lower pipe body 22 and the upper ring groove 221. A locking screw 24 penetrates through the second screw holes 223. The second screw holes 223 are vertically communicated with the upper ring groove 221. A side ring groove 222 is formed on the outer side wall of the lower pipe body 22.

[0058] As an improvement of the above technical solution, the top end of the upper pipe body 21 is bent outward to form a retaining ring 211. The retaining ring 211 abuts against the surface of the soil layer 12 between piles. A plurality of first screw holes 2111 are formed on the surface of the retaining ring 211. The first screw holes 2111 are connected with a first lifting ring 23 or a perfusion support assembly 3 in a matching manner. An insertion ring 212 matched with the upper ring groove 221 is arranged at the bottom end of the upper pipe body 21. The insertion ring 212 and the lower pipe body 22 are fixed by a locking screw 24.

[0059] The design of the retaining ring 211 enables the quick positioning of the protection assembly 2 formed by the upper pipe body 21 and the lower pipe body 22. During the perfusion stage, the perfusion support assembly 3 is installed at the top of the retaining ring 211. During the pile demolition stage, the first lifting ring 23 is installed at the top of the retaining ring 211. In this way, the retaining ring 211 can be converted into different modes according to the construction stage, with continuous operation and simplified construction steps.

[0060] As an improvement of the above technical solution, the perfusion support assembly 3 includes side frame bodies 31 and a steel cage guiding ring 32. The two side frame bodies 31 are symmetrically installed on the retaining ring 211. A steel cage guiding ring 32 is arranged between the two side frame bodies 31. The steel cage guiding ring 32 is used to guide and constrain the installation process of the steel cage. An embedded lifting assembly 4 is installed at the bottom surface of the steel cage guiding ring 32. The bottom end of the embedded lifting assembly 4 is embedded into the steel pile body 512.

[0061] The steel cage guiding ring 32 can guide the steel cage, making the installation of the steel cage more convenient. It can be accurately placed at the center line of the pile hole 13, improving the installation efficiency of the steel cage.

[0062] As an improvement of the above technical solution, the embedded lifting assembly 4 includes a connecting ring plate 41, a sleeve 42, and an anchor rod 43; a plurality of sleeves 42 are vertically provided on the bottom surface of the connecting ring plate 41, and an anchor rod 43 is inserted into each sleeve 42. An assembly hole 432 is provided at the top end of the anchor rod 43, and barbs 431 are provided on the outer wall of the bottom end. The anchor rod 43 is embedded in the steel bar inner pile body 512. A third screw hole 411 is provided on the surface of the connecting ring plate 41, and the third screw hole 411 is cooperatively connected to the steel bar cage guiding ring 32 or the second lifting ring 44.

[0063] The steel bar cage guiding ring 32 can also be used as the installation structure of the embedded lifting assembly 4. In this way, the anchor rod 43 can be reserved during the pouring stage. When lifting the steel bar inner pile body 512, the worker can directly connect the lifting device to the embedded lifting assembly 4. At the same time, the anchor rod 43 can be vertically placed at the center of the steel bar inner body. In this way, during subsequent lifting, the lifting center of gravity of the steel bar inner pile body 512 coincides highly with the center line of the steel bar inner pile body 512, avoiding the steel bar inner pile body 512 from tilting during lifting and bending the cap steel bars 6; when the traditional steel bar inner pile body 512 is lifted, the worker hammers the anchor rod 43 into the steel bar inner pile body 512 alone. The layout of the anchor rod 43 is troublesome, and the lifting center of gravity is easily deviated from the center line of the steel bar inner pile body 512, resulting in the steel bar inner pile body 512 often tilting during lifting, and then bending the cap steel bars 6. If the bending is not much, it can still be used after subsequent correction. If the cap steel bars 6 are bent too much or broken, the worker needs to continue the steel bars, and the repair is very troublesome;

[0064] The bottom of the above anchor rod 43 is provided with barbs 431, and the anchoring effect is better. An assembly hole 432 is provided at the upper part. In this way, the anchor rod 43 and the sleeve 42 can be connected by screws. After the lifting is completed, the sleeve 42 and the anchor rod 43 can be separated for the recycled use of the connecting ring plate 41 and the sleeve 42.

[0065] Embodiment 2

[0066] As Figure 7 and Figure 8 shown, on the basis of the above embodiment, in order to enable the latter protection unit to achieve the above functions, the following content is further given in this embodiment:

[0067] The waterproof component includes a waterproof expansion rubber sleeve 7, a concrete cushion layer 9, a cementitious capillary crystalline waterproof coating 9a, a polymer cement waterproof layer 9b, a coiled material waterproof layer 9c, and a fine aggregate concrete layer 9d. A waterproof expansion rubber sleeve 7 is sleeved on the root of the pile cap steel bars 6. The concrete cushion layer 9 is circularly laid on the foundation soil layer 11. The cementitious capillary crystalline waterproof coating 9a is laid on the surface of the concrete cushion layer 9, the surface of the lower pipe body 22, and the surface of the pile foundation. The coiled material waterproof layer 9c is laid on the surface of the cementitious capillary crystalline waterproof coating 9a. The coiled material waterproof layer 9c is pressed into the upper annular groove 221 through the first pressing ring 9e and into the side annular groove 222 through the second pressing ring 9f. The fine aggregate concrete layer 9d is laid on the surface of the coiled material waterproof layer 9c.

[0068] The above-mentioned multiple protective layers can effectively ensure the waterproof and sealing effects at various positions; the waterproof expansion rubber sleeve 7 can seal the connection between the pile cap steel bars 6 and the pile head foundation 511; the lower pipe body 22 can enclose the connection between the foundation soil layer 11 and the pile head foundation 511 and protect this place.

[0069] Using a whole coiled material waterproof layer 9c, there is no splicing seam at the connection between the foundation soil layer 11 and the pile head foundation 511, and the protection effect is better. Moreover, by using the cooperation between the pressing ring and the reserved annular groove of the lower pipe body 22, the coiled material part can be pressed into the annular groove, which can prevent the coiled material from resetting and warping.

[0070] The steel bar protection cover 8 includes a main frame 81, expansion columns 82, a guide frame 83, and a clamping assembly 84. The main frame 81 includes a first plate body 811 and a first support plate 812. Four annularly arranged first support plates 812 are provided on the bottom surface of the first plate body 811. The bottom end of each first support plate 812 vertically penetrates through the clamping assembly 84. The inner ends of the four clamping assemblies 84 clamp the outer wall of the fine aggregate concrete layer 9d. A perforation is provided at the center of the first plate body 811. The guide frame 83 includes an annular cover 831 and a second support plate 832. The second support plate 832 is vertically provided on the surface of the first plate body 811. The second support plates 832 are symmetrically arranged on both sides of the perforation. The annular cover 831 is provided at the top end of the second support plate 832. The expansion column 82 includes a tapered column 821 and a second plate body 822. The second plate body 822 is provided at the top end of the tapered column 821. The second plate body 822 is vertically slidably connected to the annular cover 831 and the second support plate 832. The second plate body 822 is cooperatively stopped on the surface of the first plate body 811. The maximum outer diameter of the tapered column 821 is the same as the inner diameter of the perforation. The downward moving tapered column 821 synchronously expands each pile cap steel bar 6 outward.

[0071] The inner wall of the guiding frame 83 is provided with a vertical groove 8311. Sliders 8221 are arranged on both sides of the baffle plate, and the sliders 8221 are slidably embedded in the vertical groove 8311. The clamping assembly 84 includes an adjusting screw 841 and a pressing plate 842. The adjusting screw 841 penetrates through the first support plate 812, and the pressing plate 842 is arranged at the inner end of the adjusting screw 841.

[0072] The above-mentioned main frame 81 can shield and protect the bearing platform steel bars 6 from above, preventing external stones and equipment from hitting the bearing platform steel bars 6, ensuring that the bearing platform steel bars 6 can be stably maintained in an inclined state and have a complete structure before the bearing platform is installed.

[0073] Multiple clamping assemblies 84 can position the main frame 81 in the circumferential direction, preventing the main frame 81 from shifting under force and improving the protection effect of the main frame.

[0074] When the external hammer strikes the expansion column 82, it can drive the expansion column 82 to move downward along the guiding frame 83. In this way, the expansion column 82 can simultaneously expand each bearing platform steel bar 6, enabling the bearing platform steel bars 6 to be quickly bent to the appropriate inclination angle, greatly improving the bending efficiency of the bearing platform steel bars 6 and eliminating the inclination angle error caused by traditional manual bending one by one. The expansion column 82 can also support each bearing platform steel bar 6 from the inside to ensure the structural stability of the bearing platform steel bars 6.

[0075] Embodiment Three

[0076] The construction method of the pile head protection system for cast-in-place piles 5 in a complex construction environment, the construction method includes the following steps:

[0077] S1. Protection of the front section of the pile head:

[0078] Install the integrated protection component 2 at the inner top of the pile hole 13, and the upper pipe body 21 of the protection component 2 is placed on the surface of the soil layer between piles 12.

[0079] Install the perfusion support component 3 and the embedded lifting component 4 on the surface of the upper pipe body 21.

[0080] Pass the steel reinforcement cage through the perfusion support component 3 and put it into the pile hole 13.

[0081] Pour concrete into the pile hole 13, and the pile head is formed in the upper pipe body 21 and the lower pipe body 22 to obtain the cast-in-place pile 5. The bottom end of the embedded lifting component 4 is embedded into the pile body 512 of the steel bars.

[0082] S2. Protection of the middle section of the pile head:

[0083] Dismantle the perfusion support component 3.

[0084] Clean the soil between piles. During the cleaning process, the upper pipe body 21 and the lower pipe body 22 protect the pile head to prevent the pile head from being accidentally damaged.

[0085] Unscrew the locking screw 24 at the connection between the upper pipe body 21 and the lower pipe body 22, install the first lifting ring 23 on the upper pipe body 21, and then lift the upper pipe body 21 to expose the upper part of the pile body main body;

[0086] The worker breaks the outer pile body 513 of the steel bar along the upper pipe body 21, chisels through the root of the inner pile body 512 of the steel bar, and then installs the second lifting ring 44 on the embedded lifting assembly 4 to lift the inner pile body 512 of the steel bar, and the lower pipe body 22 always protects the pile head foundation 511;

[0087] S3. Protection of the rear pile head:

[0088] Lay a waterproof component on the surfaces of the pile head foundation 511 and the foundation soil layer 11;

[0089] Install the main frame 81 outside the pile head foundation 511, adjust each clamping component 84 so that the clamping component 84 is clamped and positioned outside the pile head foundation 511, and vertically hammer the expansion column 82 into each pile cap steel bar 6 along the guide frame 83. The expansion column 82 synchronously drives each pile cap steel bar 6 to bend outward by 70°; in this way, the main frame 81 and the expansion column 82 can protect the bent pile cap steel bars 6.

[0090] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0091] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. The pile head protection system for cast-in-place piles under complex construction environments, characterized in that: The pile head protection system includes a front section protection unit, a middle section protection unit, and a rear section protection unit. A pile hole is formed inside a building foundation pit. The bottom of the building foundation pit is the foundation soil layer, and the top is the soil layer between piles. A cast-in-place pile is poured in the pile hole. The exposed part at the top of the cast-in-place pile is the pile head main body. The bottom of the pile head main body is the pile head foundation. The pile head foundation extends outward upward with a circular array of bearing platform steel bars. The inner side of the bearing platform steel bars is the inner steel pile body, and the outer side is the outer steel pile body; The front section protection unit is arranged during the formation of the cast-in-place pile and the cleaning of the soil between piles. The front section protection unit includes an upper pipe body and a lower pipe body. The pile head main body is formed inside the upper pipe body and the lower pipe body. The upper pipe body is stopped and embedded in the inner top of the pile hole, and the lower pipe body is detachably installed flush at the bottom end of the upper pipe body. The assembled upper pipe body and lower pipe body are used to shape and protect the pile head main body during the pouring stage and the stage of cleaning the soil between piles; The middle section protection unit is arranged during the breaking of the inner steel pile body and the outer steel pile body. The middle section protection unit includes a lower pipe body, and the lower pipe body is used to protect the pile head foundation; The rear section protection unit is arranged after the pile head is broken. The rear section protection unit includes a waterproof component, a steel bar protection cover, and a lower pipe body. The waterproof component is laid on the surfaces of the pile head foundation, the lower pipe body, and the foundation soil layer. The steel bar protection cover covers the outside of the bearing platform steel bars; The waterproof component includes a waterproof expansion rubber sleeve, a concrete cushion layer, a cementitious capillary crystalline waterproof coating, a polymer cement waterproof layer, a coiled material waterproof layer, and a fine aggregate concrete layer. A waterproof expansion rubber sleeve is sleeved on the root of the bearing platform steel bars. The concrete cushion layer is laid circularly on the foundation soil layer. The cementitious capillary crystalline waterproof coating is laid on the surfaces of the concrete cushion layer, the lower pipe body, and the pile body foundation. The coiled material waterproof layer is laid on the surface of the cementitious capillary crystalline waterproof coating. The fine aggregate concrete layer is laid on the surface of the coiled material waterproof layer; The steel bar protection cover includes a main frame, expansion columns, a guiding frame, and a clamping component. The main frame includes a first plate body and a first support plate. Four circularly arranged first support plates are provided on the bottom surface of the first plate body. Each first support plate is vertically penetrated by a clamping component at the bottom end. The inner ends of the four clamping components clamp the outer wall of the fine aggregate concrete layer. A through hole is opened at the center of the first plate body. The guiding frame includes a ring cover and a second support plate. The second support plate is vertically arranged on the surface of the first plate body. The second support plates are symmetrically arranged on both sides of the through hole. A ring cover is provided at the top end of the second support plate. The expansion column includes a tapered column and a second plate body. The tapered column is provided with a second plate body at the top end. The second plate body is vertically slidably connected to the ring cover and the second support plate. The second plate body cooperates with and stops against the surface of the first plate body. The maximum outer diameter of the tapered column is the same as the inner diameter of the through hole. The downward moving tapered column synchronously expands each bearing platform steel bar outward; 2. The cast-in-place pile head protection system in a complex construction environment according to claim 1, wherein: An upper ring groove is opened on the surface of the lower pipe body. A plurality of second screw holes are opened at the positions of the outer wall of the lower pipe body corresponding to the upper ring groove. Locking screws penetrate through the second screw holes. The second screw holes are vertically communicated with the upper ring groove. A side ring groove is opened on the outer side wall of the lower pipe body.

3. The cast-in-place pile head protection system under complex construction environment according to claim 2, wherein: The top end of the upper pipe body is bent outward to form a retaining ring, the retaining ring stops at the surface of the soil layer between the piles, and a plurality of first screw holes are formed on the surface of the retaining ring. The first screw holes are connected with a first lifting ring or a grouting support assembly in a matching manner. The bottom end of the upper pipe body is provided with an insertion ring that matches with the upper ring groove, and the insertion ring and the lower pipe body are fixed by locking screws.

4. The cast-in-place pile head protection system in a complex construction environment according to claim 3, characterized in that: The grouting support assembly includes a side frame body and a steel reinforcement cage guiding ring. The two side frame bodies are symmetrically installed on the retaining ring, and a steel reinforcement cage guiding ring is arranged between the two side frame bodies. The steel reinforcement cage guiding ring is used to guide and restrict the installation process of the steel reinforcement cage; a pre-buried lifting assembly is installed on the bottom surface of the steel reinforcement cage guiding ring, and the bottom end of the pre-buried lifting assembly is pre-buried into the steel reinforcement inner pile body.

5. The cast-in-place pile head protection system in a complex construction environment according to claim 4, characterized in that: The pre-buried lifting assembly includes a connecting ring plate, a sleeve, and an anchor rod; a plurality of sleeves are vertically arranged on the bottom surface of the connecting ring plate, and an anchor rod is inserted into each sleeve. An assembly hole is formed at the top end of the anchor rod, and barbs are formed on the outer wall of the bottom end. The anchor rod is pre-buried into the steel reinforcement inner pile body. Third screw holes are formed on the surface of the connecting ring plate, and the third screw holes are connected with the steel reinforcement cage guiding ring or a second lifting ring in a matching manner.

6. The cast-in-place pile head protection system in a complex construction environment according to claim 5, characterized in that: The coiled material waterproof layer is pressed into the upper ring groove by a first pressing ring and into the side ring groove by a second pressing ring.

7. The construction method of the cast-in-place pile head protection system under complex construction environments according to claim 6, characterized in that, The shown construction method includes the following steps: S1. Protection of the front-section pile head: Install a protection assembly assembled into one body at the inner top of the pile hole, and the upper pipe body of the protection assembly is erected on the surface of the soil layer between the piles; Install the grouting support assembly and the pre-buried lifting assembly on the surface of the upper pipe body; Pass the steel reinforcement cage through the grouting support assembly and put it into the pile hole; Pour concrete into the pile hole, and the pile head is formed in the upper pipe body and the lower pipe body to obtain a cast-in-place pile. The bottom end of the pre-buried lifting assembly is pre-buried into the steel reinforcement inner pile body; S2. Protection of the middle-section pile head: Dismantle the grouting support assembly; Clean the soil between the piles. During the cleaning process, the upper pipe body and the lower pipe body protect the pile head to prevent accidental damage to the pile head; Unscrew the locking screws at the connection between the upper pipe body and the lower pipe body, install the first lifting ring on the upper pipe body, and then lift the upper pipe body to expose the upper part of the pile body main body; The worker breaks the outer pile body of the steel reinforcement along the top surface of the lower pipe body, chisels through the root of the inner pile body of the steel reinforcement, and then installs the second lifting ring on the pre-buried lifting assembly to lift the inner pile body of the steel reinforcement. The lower pipe body always protects the pile head foundation; S3. Protection of the rear-section pile head: Lay a waterproof assembly on the surface of the pile head foundation and the foundation soil layer; Install the main frame outside the pile head foundation, adjust each clamping assembly so that the clamping assembly is clamped and positioned outside the pile head foundation, and hammer the expansion columns vertically along the guiding frame into each pile cap steel bar. The expansion columns synchronously drive each pile cap steel bar to bend outward by 70°; in this way, the main frame and the expansion columns can protect the bent pile cap steel bars.

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