Prefabricated tubular pile, prefabricated tubular pile construction method and pile foundation structure

Abstract

The invention discloses a prefabricated pipe pile, a prefabricated pipe pile construction method and a pile foundation structure. Comprising the following steps that a pile plug is inserted into the end of a hollow pipe pile body to form a prefabricated pipe pile, and the prefabricated pipe pile is pressed into soil with the preset depth; the water-permeable bag filled with the high-water-stop filler is put into the pipe pile body, the water-permeable bag in the pipe pile body is compacted so that a water sealing plug can be formed on the pile plug, and feeding and compacting are continuously conducted till the preset water-stop condition is met; and the water sealing plug is pressed so that the pile plug can be separated from the pipe pile body, and filler is put into the pipe pile body till the preset termination condition is met. According to the method, the piping phenomenon can be avoided through the filled high-water-stop filler, and the subsequently formed water sealing plug can achieve the effects of absorbing water and physically preventing soft mud from entering; the squeezing and expanding guiding type and opening and closing type pile tip is adopted, a transverse squeezing and expanding reinforcing body can be formed at the pile end of the saturated soft soil layer pipe pile, and the problems that the water sealing capacity is poor and the bearing capacity is insufficient in the saturated soft soil layer early-stage filler reinforcing process are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of civil engineering, and in particular to a prefabricated pipe pile, a prefabricated pipe pile construction method and a pile foundation structure. Background Art

[0002] In the field of building pile foundations, high-strength prefabricated pipe piles that are prefabricated in factories are gradually being used in various types of buildings because of their advantages of high pile strength, stable quality, high single pile bearing capacity, short construction period and low cost. When prefabricated pipe piles are used for construction in coastal water-rich soft soil strata, the bearing capacity of the pipe piles is low, and even pile sinking may occur. A significant increase in pile length or pile diameter will lead to increased pile sinking resistance, excessive cost and damage to the pile end. Therefore, reinforcing the pile end of the prefabricated pipe pile and improving the pile end bearing capacity is an economically feasible method to improve the overall bearing capacity of the prefabricated pipe piles.

[0003] During the construction process, it was found that when the groundwater level is very high and the water pressure is high in the soil environment, the problem of poor water sealing ability is prone to occur during the early filling reinforcement process of the pipe piles. Specifically, due to the limited filling speed of the gap filling method, a part of the loose filler is attached to the upper part of the rammer and the wall of the prefabricated pipe pile hole, and the water sealing effect of the pile bottom is insufficient during the filling process. After the soil at the bottom of the pipe pile is disturbed by the impact, a large amount of water and soft mud flows into the interior of the pipe pile, resulting in the inability to continue ramming to form an enlarged head at the bottom of the pile, or resulting in the presence of soft mud interlayers in the enlarged head formed by the filling reinforcement.

[0004] In addition, field tests found that when the ends of precast pipe piles in water-rich soft soil layers were reinforced by ramming fillers, the pile end reinforcement body formed always tended to expand downward, while the lateral expansion effect was insufficient, resulting in little improvement in the bearing capacity of the reinforced pile ends of small and medium diameter precast pipe piles. The bearing capacity of the reinforced precast pipe pile ends after construction has not been significantly improved. Summary of the invention

[0005] The present invention provides a prefabricated pipe pile, a prefabricated pipe pile construction method and a pile foundation structure, aiming to solve the problem of poor water sealing ability in the early stage filling material reinforcement process in the prior art.

[0006] A first aspect of the present invention provides a prefabricated pipe pile construction method, comprising the following steps:

[0007] Inserting a pile plug into the end of a hollow pipe pile body to form a prefabricated pipe pile, and pressing the prefabricated pipe pile into the soil at a preset depth;

[0008] Putting a water-permeable bag filled with high water-stopping filler into the pipe pile body, and compacting the water-permeable bag in the pipe pile body to form a water-sealing plug on the pile plug, and continuing to put in materials and compact until the preset water-stopping conditions are met, wherein the pile plug remains inserted into the pipe pile body;

[0009] The water sealing plug is pressed to separate the pile plug from the pipe pile body, and filler is added into the pipe pile body until a preset termination condition is met.

[0010] In some embodiments of the first aspect, the components of the high water-stop filler include dry quicklime, dry waste incineration secondary bottom ash fine sand, and a mixture of dry cement and waste incineration secondary bottom ash fine sand;

[0011] The method of placing high water-stop filler into a water-permeable bag comprises the following steps:

[0012] First, the quicklime is filled into the water permeable bag;

[0013] Then, the waste incineration secondary bottom ash fine sand is filled into the water permeable bag;

[0014] Finally, the mixture of the cement and the fine sand of the secondary bottom ash from waste incineration is filled into the water-permeable bag.

[0015] In some embodiments of the first aspect, the volume of the quicklime is 1 / 10 to 1 / 6 of the volume of the permeable bag;

[0016] The volume of the fine sand from the secondary bottom ash of garbage incineration is 1 / 3 to 1 / 2 of the volume of the permeable bag;

[0017] The volume of the mixture of the cement and the fine sand from the secondary bottom ash of waste incineration is 1 / 3 to 1 / 2 of the volume of the permeable bag, and the mass ratio of the cement to the fine sand from the secondary bottom ash of waste incineration in the mixture is 1:3 to 1:5.

[0018] In some embodiments of the first aspect, in the step of placing the water-permeable bag filled with high water-stop filler into the pipe pile body, the outer peripheral side surface of a single water-permeable bag abuts against the inner peripheral wall of the pipe pile body.

[0019] In some embodiments of the first aspect, the water permeable bag is a woven mesh bag.

[0020] In some embodiments of the first aspect, the height of the water sealing plug is 5-30 cm.

[0021] In some embodiments of the first aspect, the preset water-stopping condition is that the water content at the top of the water sealing plug is less than a preset value.

[0022] In some embodiments of the first aspect, a filler is added to the pile body until a preset termination condition is met. Specifically, in this step, the filler is added to the pile body until a preset termination condition is met.

[0023] Adding bearing layer reinforcement filler into the pipe pile body until a first preset termination condition is met;

[0024] A core filling material is added into the pipe pile body until a second preset termination condition is met.

[0025] In some embodiments of the first aspect, the step of adding a bearing layer reinforcement filler into the pile body until a first preset termination condition is met is specifically as follows:

[0026] A watertight bag filled with a bearing layer reinforcement filler is put into the pipe pile body until the first preset termination condition is met.

[0027] In some embodiments of the first aspect, the components of the bearing layer reinforcement filler include dry hard cement mortar and crushed stone, the mass ratio of the dry hard cement mortar to the crushed stone is 1:1 to 1:2.5, and the particle size of the crushed stone is less than or equal to 6 mm;

[0028] The components of the dry hard cement mortar include water, cement and secondary bottom ash from waste incineration, and the mass ratio of the cement to the secondary bottom ash from waste incineration is 1:3-1:5.

[0029] The second aspect of the present invention provides a prefabricated pipe pile, which is used in the prefabricated pipe pile construction method described in the first aspect, and includes a hollow pipe pile body, a pile plug and a sealing member;

[0030] The pile plug is inserted into the end of the pipe pile body; the pile plug can be separated from the pipe pile body after being subjected to a preset pressure;

[0031] The sealing member can be elastically clamped between the pipe pile body and the pile plug.

[0032] In some embodiments of the second aspect, the prefabricated pipe pile further comprises a plurality of suspension ropes;

[0033] One end of the lifting rope is connected and fixed to the pipe pile body, and the other end of the lifting rope is connected and fixed to the pile plug.

[0034] In some embodiments of the second aspect, the pile plug has an extrusion and expansion guide section, and the pile diameter of the extrusion and expansion guide section gradually increases along the direction from the tubular pile body to the pile plug.

[0035] In some embodiments of the second aspect, along the direction from the pipe pile body to the pile plug, the pile plug sequentially comprises an upper extrusion and expansion guide section, a platform section and a lower extrusion and expansion guide section;

[0036] The maximum pile diameter of the upper extrusion and expansion guide section is less than or equal to the minimum pile diameter of the lower extrusion and expansion guide section;

[0037] The stage is used to clamp the pile plug onto the pipe pile body.

[0038] In some embodiments of the second aspect, the pile plug includes a connecting seat and a plurality of pile petals, wherein the plurality of pile petals are arranged on the peripheral side of the connecting seat, the pile petals are hinged to the connecting seat, and the plurality of pile petals can be flipped to surround the connecting seat or can be flipped and unfolded.

[0039] In some embodiments of the second aspect, the prefabricated pipe pile further includes a bladder cap;

[0040] The pouch cap comprises a cap body and a brim;

[0041] The circumference of the cap body is connected with a circle of the cap brim;

[0042] The cap body is arranged above the pile plug, and the cap brim is connected and fixed to the pipe pile body.

[0043] A third aspect of the present invention provides a pile foundation structure, which is obtained by applying the prefabricated pipe piles described in the second aspect to the prefabricated pipe pile construction method described in the first aspect.

[0044] It can be seen from the above technical solutions that the present invention has the following advantages:

[0045] The present embodiment provides a method for constructing prefabricated pipe piles. Since the method involves throwing a permeable bag filled with a high water-stop filler into the pipe pile body, the filler in the permeable bag will not scatter inside the pipe pile body after filling, thereby preventing the bulk-thrown filler from being directly lifted up by pressurized water due to its too small dry density, thereby causing pipe bursting. Furthermore, since the pile plug remains inserted into the pipe pile body and the filled permeable bag in the pipe pile body is compacted, a water-sealing plug will be formed on the pile plug. Therefore, the water-sealing plug is equivalent to forming a water-absorbing plug at the end of the pipe pile body. The filler in the water-sealing plug can absorb a large amount of water, thereby preventing a large amount of water from pouring into the hollow interior of the prefabricated pipe pile. The water-sealing plug can also play a role in physically blocking the entry of soft mud, thereby effectively solving the problem of poor water-sealing ability in the early filling reinforcement process in the prior art.

[0046] The present embodiment provides a pile foundation structure. When the pile end filler of the existing water-rich soft soil layer is reinforced, due to the insufficient restraining capacity of the lower stratum, most of the filler is vertically filled in the lower part of the prefabricated pipe pile, and the diameter of the formed reinforcement body does not exceed the diameter of the prefabricated pipe pile, and the bearing capacity improvement ratio of the reinforced pile is relatively low; the pile foundation structure of the present embodiment adopts an extrusion-guided and opening-and-closing pile tip to guide the filler to radially fill the prefabricated pipe pile during the filler reinforcement process; it is conducive to the formation of a large-volume reinforcement body with transverse extrusion at the pile end of the pipe pile in the saturated soft soil layer, and the pile foundation structure formed can significantly improve the bearing capacity of the reinforced pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0048] Figure 1 A schematic flow chart of a prefabricated pipe pile construction method provided in the first aspect of an embodiment of the present invention;

[0049] Figure 2 A schematic diagram of the construction process of a prefabricated pipe pile construction method provided in the first aspect of an embodiment of the present invention;

[0050] Figure 3 A schematic diagram of the overall structure of a prefabricated pipe pile with a hanging rope provided in the second aspect of an embodiment of the present invention;

[0051] Figure 4 A schematic structural diagram of an upper hinged opening and closing pile plug provided in accordance with a second aspect of an embodiment of the present invention;

[0052] Figure 5 A schematic diagram of the unfolded structure of the upper hinged retractable pile plug provided in the second aspect of the embodiment of the present invention;

[0053] Figure 6 A schematic structural diagram of a connecting socket provided in accordance with a second aspect of an embodiment of the present invention;

[0054] Figure 7 A schematic diagram of the structure of an upper hinged opening and closing stump petal provided in the second aspect of an embodiment of the present invention;

[0055] Figure 8 A schematic diagram of the structure of a lower hinged opening and closing pile plug provided in the second aspect of an embodiment of the present invention;

[0056] Fig. 9 A schematic diagram of the structure of the lower hinged opening and closing stump petal provided in the second aspect of the embodiment of the present invention;

[0057] Fig.10 A schematic structural diagram of a sealing member provided in accordance with a second aspect of an embodiment of the present invention;

[0058] Fig.11 A schematic diagram of the overall structure of a prefabricated pipe pile with a bag cap provided in the second aspect of an embodiment of the present invention;

[0059] Fig.12 A schematic structural diagram of a pile foundation structure with a suspension rope provided in accordance with a third aspect of an embodiment of the present invention;

[0060] Fig.13A schematic structural diagram of a pile foundation structure with a bag cap provided in the third aspect of an embodiment of the present invention.

[0061] Reference numerals:

[0062] 1. Pipe pile body; 2. Pile plug; 20. Upper extrusion guide section; 21. Platform stage; 22. Lower extrusion guide section; 23. Connecting seat; 24. Pile flap; 25. Bag cap; 3. Sealing element; 4. Lifting rope; 5. High water-stop filler; 6. Pile foundation structure; a. Extrusion reinforcement body; b. Compacted soil; c. Influenced soil. DETAILED DESCRIPTION

[0063] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and drawings of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0065] In the prefabricated pipe piles and construction methods in water-rich soft soil strata, the study found that the prefabricated pipe piles would have poor water-sealing ability during the early filling reinforcement process. Due to the limited filling speed of the gap filling method, a part of the loose filler adheres to the upper part of the rammer and the wall of the prefabricated pipe pile hole, and the water-sealing effect of the pile bottom is insufficient during the filling process. After the soil at the bottom of the pipe pile is disturbed by the impact, a large amount of water and soft mud flows into the pipe pile, resulting in the inability to continue ramming to form an enlarged head at the bottom of the pile, or causing the enlarged head formed by the filling reinforcement to have a soft mud interlayer. It is necessary to enhance the water-sealing ability of the reinforcement process and improve the quality of the pile bottom reinforcement body.

[0066] In addition, the study also found that when the pile ends of small and medium-diameter prefabricated pipe piles are reinforced with ramming fillers in water-rich soft soil layers, the pile end reinforcement body formed always tends to expand downward, while the lateral expansion effect of the reinforcement body is insufficient, resulting in limited improvement in the bearing capacity of the pile ends of small and medium-diameter prefabricated pipe piles. It is urgent to increase the lateral expansion capacity of the expansion reinforcement body.

[0067] The embodiment of the present invention provides a prefabricated pipe pile construction method, which is used to solve the technical problem of poor water sealing ability in the early filling material reinforcement process in the prior art.

[0068] See also Figure 1 and Figure 2 The present embodiment provides a prefabricated pipe pile construction method, comprising the following steps:

[0069] S1, inserting the pile plug 2 into the end of the hollow pipe pile body 1 to form a prefabricated pipe pile, and pressing the prefabricated pipe pile into the soil at a preset depth, wherein the pile plug 2 can be separated from the pipe pile body 1 after being subjected to a preset pressure;

[0070] S2, putting a water-permeable bag filled with high water-stopping filler 5 into the pipe pile body 1, and compacting the filled water-permeable bag in the pipe pile body 1 to form a water-sealing plug on the pile plug 2, and continue to put in materials and compact until the preset water-stopping conditions are met, wherein the pile plug 2 remains inserted into the pipe pile body 1;

[0071] S3, pressing the water-sealing plug to separate the pile plug 2 from the pile body 1, and adding filler into the pile body 1 until the preset termination condition is met.

[0072] In this embodiment, the pile plug 2 is inserted into the end of the pipe pile body 1 to form a prefabricated pipe pile, and the prefabricated pipe pile is pressed into the soil at a preset depth, so that the prefabricated pipe pile forms a structure with one end closed and the other end open, so as to perform water sealing treatment during the early filling process; a permeable bag filled with high water-stop filler 5 is put into the pipe pile body 1. Since the high water-stop filler 5 is put into the pipe pile body 1 after being filled in the permeable bag, the high water-stop filler 5 will not be scattered in the pipe pile body 1, and its dry density will not be too small to be directly lifted up by the pressure water, which can avoid the occurrence of pipe bursts; after the permeable bag is compacted on the pile plug 2 to form a water-sealing plug, the high water-stop filler 5 in the water-sealing plug can continuously absorb water, and the water-sealing plug and the pile plug 2 can cooperate to block the entry of soft mud and avoid the formation of a soft mud layer inside the pipe pile body 1; the water-sealing plug is pressed to separate the pile plug 2 from the pipe pile body 1, and filler is put into the pipe pile body 1 until the preset termination condition is met to form a pile foundation structure 6.

[0073] Compared with the prior art, the present invention has the following advantages: first, it can avoid the occurrence of pipe bursting, that is, the present embodiment puts the bagged high water-stop filler 5 into the pipe pile body 1. Compared with the prior art of lime in bulk, on the one hand, it can prevent the lime in bulk from being directly lifted up due to its too small dry density, thereby causing pipe bursting; on the other hand, it can slow down the speed of water entering the lime, thereby avoiding the gradual accumulation of a weak mud layer in the hollow of the prefabricated pipe pile during the reinforcement process, thereby affecting the tamping energy; second, it can fully absorb water and block the entry of soft mud. When sealing water and feeding, the pile plug 2 remains on the pipe pile body 1, and the high water-stop filler 5 can form a water-sealing plug inside the pipe pile body 1. The high water-stop filler 5 in the water-sealing plug can give full play to its water absorption performance. The cooperation of the water-sealing plug and the pile plug 2 can physically block the influx of soft mud. It can be seen that this embodiment can effectively solve the technical problems of a large amount of water and soft mud influxing into the interior of the pipe pile due to the high groundwater level in the water-rich soft soil layer, resulting in the inability to continue tamping to form a pile bottom reinforcement body or the reinforcement body formed by the conventional tamping reinforcement method is seriously enclosed in mud.

[0074] This technical solution can promote the traditional carrier pile and pile end reinforcement construction technology to water-rich soft soil construction sites such as coastal areas, and has good application prospects.

[0075] As an example, Figure 2 As shown, a feasible method for pressing the prefabricated pipe piles into the soil in step S1 is further provided. The prefabricated pipe piles can be pressed into the soil at a preset depth by static pressure, hammering, etc. When the designed pile top elevation of the prefabricated pipe pile is lower than the ground elevation, a pile cap can be installed on the prefabricated pipe pile top to assist the construction tools in pressing the prefabricated pipe pile into the designed depth.

[0076] As an example, Figure 2 As shown, an achievable method in step S2 is further provided. In the entire step S2, the pile plug 2 remains inserted into the pipe pile body 1. Step S2 specifically includes the following steps:

[0077] S20 , putting the water-permeable bag filled with high water-stop filler 5 into the pile body 1 .

[0078] In one embodiment, in order to meet the purpose of sufficient water absorption and maintaining the structural strength of the material, the components of the high water-stop filler 5 include dry quicklime, dry waste incineration secondary bottom ash fine sand and a mixture of dry cement and waste incineration secondary bottom ash fine sand, and the method of loading the high water-stop filler 5 into a permeable bag specifically includes the following steps: first, loading quicklime into the permeable bag; then, loading the waste incineration secondary bottom ash fine sand into the permeable bag; finally, loading the mixture of cement and waste incineration secondary bottom ash fine sand into the permeable bag.

[0079] In specific implementation, after the high water-stop filler 5 is filled into the water-permeable bag in the above order, a three-layer water-absorbing structure will be formed in the water-permeable bag. The first layer is quicklime, the second layer is fine sand from secondary bottom ash of garbage incineration, and the third layer is a mixture of cement and fine sand from secondary bottom ash of garbage incineration. After forming this three-layer structure, the advantages of each layer structure are:

[0080] The first layer is quicklime. Quicklime itself has good water absorption performance, but its piled state when dry is very loose. First, it cannot be compacted by tamping. Second, because the lime in the loose piled state has too light a specific gravity, it will not absorb water at the same time under the action of pressurized water. After research, it was found that when a cylinder is filled with lime and water pressure is applied inward on the bottom of the cylinder, it can be found that when clear water first appears on the upper surface of the cylinder, it is similar to the appearance of a small spring, while the lime around the spring is still dry, and then it will spread and soak around the spring. In other words, if only lime is used, it is difficult to seal the gushing water;

[0081] The second layer is fine sand from the secondary bottom ash of garbage incineration. The fine sand from the secondary bottom ash of garbage incineration has a smaller particle size, a lower permeability coefficient, is more flaky, and has a larger specific surface area, but it is not as fine as clay and does not have such a hydrophilic structure. Therefore, from the effect point of view, if fine sand from the secondary bottom ash of garbage incineration is used, on the one hand, its water absorption and water-proof performance are better than ordinary fine sand. On the other hand, it is easier to form than clay when hammered (clay is easy to become mud), and the permeability coefficient is not too small, which makes it difficult for the filler to be compressed and moved around. In addition, the fine sand from the secondary bottom ash of garbage incineration also has a certain gelling activity;

[0082] The third layer is a mixture of cement and fine sand from secondary bottom ash from waste incineration. This layer of material is easier to shape under the action of tamping and expansion, and has better strength after hardening. Because of the buffering of the first two layers of materials, the cement will not be diluted too quickly by the gushing water.

[0083] It can be seen that the setting of the three layers of materials inside the permeable bag, due to the different resistance and adsorption force of different layers, the liquid will have sufficient time and contact area to be continuously adsorbed and retained when passing through each layer, so that the water absorption performance of the entire permeable bag is from strong to weak, and the structural strength is from weak to strong, which not only ensures that each layer of material can give full play to its water absorption performance, but also ensures the continuity of material performance.

[0084] Based on the above embodiments, the volume of quicklime is 1 / 10~1 / 6 of the volume of the permeable bag; the volume of the fine sand of secondary bottom ash from waste incineration is 1 / 3~1 / 2 of the volume of the permeable bag; the volume of the mixture of cement and fine sand of secondary bottom ash from waste incineration is 1 / 3~1 / 2 of the volume of the permeable bag, and the mass ratio of cement to fine sand of secondary bottom ash from waste incineration in the mixture is 1:3~1:5. In specific implementation, when the water level of the construction stratum is high, the volumes of quicklime and fine sand of secondary bottom ash from waste incineration take larger values, and the mass of fine sand of secondary bottom ash from waste incineration in the mixture of cement and fine sand of secondary bottom ash from waste incineration takes larger value. The formula of the proposed high water-stop filler 5 is conducive to quickly and effectively blocking water gushing from the pile end, which greatly improves the construction success rate of water-rich soft soil strata.

[0085] Among them, the particle size of the fine sand of the secondary bottom ash of garbage incineration is 0.15-4.75mm, the flake particle content of the fine sand of the secondary bottom ash of garbage incineration is 9-11%, and the apparent density of the fine sand of the secondary bottom ash of garbage incineration is 2400-2410kg / m 3 The loose bulk density of fine sand from secondary bottom slag from waste incineration is 1175-1180kg / m 3 The porosity of fine sand from secondary bottom ash from waste incineration is 50-51%, and the crushing value is 10-11%.

[0086] In one embodiment, if Figure 2 As shown, in order to improve the water storage and water absorption effect of the pipe pile body 1, the high water-stop filler 5 added in a bagged manner can be freely deformed in the pile end or soil under the influence of external force or spatial constraints. When the permeable bag filled with the high water-stop filler 5 is put into the pipe pile body 1, the outer peripheral side surface of a single permeable bag abuts against the inner peripheral wall of the pipe pile body 1, that is, when in the pipe pile body 1, the cross-section of the permeable bag filled with the high water-stop filler 5 completely covers the inner circumferential cross-section of the prefabricated pipe pile, or in other words, the single filler amount added in the bagged manner is the same as the inner diameter of the pipe pile when it is in a strip shape due to the constraint of the pipe wall. The same, wherein the height of each permeable bag in the pipe pile body 1 is 20-30 cm. In specific implementation, after the pipe pile body 1 is filled with multiple permeable bags, the multiple permeable bags form a clearly layered multi-layer water-absorbing structure inside the pipe body. When the pressurized water passes through different permeable bags, it must repeat the three-layer water-absorbing process inside the permeable bag, that is, local saturation during the water absorption process can be avoided. After the previous permeable bag reaches saturation, it can be absorbed again in the next permeable bag, avoiding the problem that once a certain area reaches saturation in the ordinary water-absorbing structure, the water absorption efficiency will be greatly reduced.

[0087] In one embodiment, in order to enhance the structural strength of the subsequent water-sealing plug and the reinforcement body, the water-permeable bag is a woven mesh bag. The pore size of the woven mesh bag is smaller than the material diameter of the high water-stop filler 5. The pore size is appropriate to ensure that the filler does not leak out. On the one hand, it has good water permeability, and on the other hand, it can fully pack the high water-stop filler 5 to absorb water. Due to the fiber structure of the woven bag, the structural strength of the water-sealing plug can be enhanced to prevent it from being dispersed or collapsed by pressurized water; at the same time, the fiber strips formed by the rupture of the woven bag under subsequent action can also be used as fiber reinforcement materials for the reinforcement body.

[0088] S21, compacting the water-permeable bag in the pipe pile body 1 by tamping or static pressure to form a water-sealing plug on the pile plug 2, that is, during the reinforcement process, the high water-stop filler 5 is further compacted and forms a cylindrical water-sealing plug with the wall of the prefabricated pipe pile.

[0089] In one embodiment, in order to take into account both waterproofing and subsequent pressure impact treatment, the height of the water plug is 5-30 cm, that is, the distance from the top surface of the water plug to the end surface of the pile body 1 adjacent to the pile plug 2 is 5-30 cm. Through experiments, it was found that when the height of the water plug is less than 5 cm, the water plug is too thin, and the pressure water will disperse or collapse the water plug. The influx will form a soft mud layer at the bottom of the inner hole of the prefabricated pile, affecting the subsequent tamping or extrusion; when the height of the water plug is greater than 30 cm, the water plug is too thick, and the subsequent pressure impact to penetrate the pile plug 2 is difficult, that is, the force of the rammer will be reduced layer by layer, which is not conducive to the detachment operation of the pile plug 2.

[0090] It should be noted that, in the specific implementation, the upper surface of the water-sealing plug must be kept at a distance of no less than 5 cm from the pile end during the entire construction process, that is, the maximum depth of the bottom end of the rammer is 5 cm higher than the hollow bottom end of the prefabricated pipe pile; when this condition is not met, the high water-stop filler 5 must be re-introduced immediately, that is, during the high water-stop filler 5 process, the water-sealing plug is formed by the bagged high water-stop filler 5, and in the subsequent filling process, the water-sealing plug is formed by the subsequent filler.

[0091] In one embodiment, a compaction reinforcement method is provided, in which the pile end filling material is reinforced by heavy hammer ramming. The rammer of the heavy hammer ramming method should be rammed at a low drop distance. The rammer drop height should be less than 2 meters. The rammer penetration distance is recorded every 5 rammings.

[0092] In one embodiment, another compaction reinforcement method is provided, in which a static press is used to clamp a push drill pipe to fill the material in a push manner; the push drill pipe is a full-length hollow circular tube structure, and the bottom end has a bottom sealing plate structure that can only be opened and closed outward; when fillers are thrown into the hollow of the push drill pipe, the bottom sealing plate structure can be opened under the action of gravity, and the fillers fall into the pile end of the prefabricated pipe pile; the bottom sealing plate structure is closed when the push drill pipe is pushed downward; the push displacement needs to be recorded during the push reinforcement process.

[0093] It should be noted that when reinforcing the pile end filling material by jacking, the upper part of the jacking drill rod should be equipped with a continuous vibration device to make the jacking drill rod produce resonance with a certain energy and frequency; the resonance of the jacking drill rod can effectively promote the filling material injected through the hollow of the jacking drill rod to fall smoothly into the pile end of the prefabricated pipe pile, and on the other hand, it can transmit vibration energy to the pile end filling material and the reinforced soil layer through the jacking drill rod, which is conducive to further improving the reinforcement effect. In particular, when the continuous vibration device is working, the clamping force of the static press should be appropriately reduced.

[0094] S22, continue feeding and compacting until the preset water stop condition is met.

[0095] During specific implementation, the quicklime at the bottom of the high water-stop filler 5 can directly absorb water at the pile end. The permeability coefficient of the fine sand of the secondary bottom slag of garbage incineration above the quicklime is further reduced after tamping and compaction, thereby reducing the permeability rate of the pile end water-sealing filler. At the same time, under the action of tamping and infiltration water flow, the quicklime and fine sand will be mixed to a certain extent, and the mixture can form a reinforced body with performance higher than the strength of the reinforced soil layer, thereby ensuring the ultimate strength of the high water-stop filler 5.

[0096] In one embodiment, the preset water-stopping condition is that the water content at the top of the water-sealing plug is less than a preset value, and the preset value can be set to 0, that is, the high water-stopping feeding and compaction operations are terminated only when the water content at the top of the water-sealing plug is 0, which proves that the pressure water near the insertion end of the prefabricated pipe pile is fully absorbed, thereby providing a guarantee for the structural strength of the pile end reinforcement body to be formed subsequently; of course, the preset value can also be set to other possible suitable values, as long as it meets the needs of technical personnel in this field.

[0097] Among them, the moisture content of the top of the water-sealing plug can be judged directly or indirectly. For example, the indirect method can be: judging according to the dryness of the construction tools used for compaction, that is, after being lifted up during a compaction operation, the part where the construction tools contact the water-sealing plug is dry and water-free. For example, when the bottom end of the rammer or the top push drill rod is dry and water-free, it can be considered that the moisture content of the top of the water-sealing plug is 0, and the construction of the high water-stop filler 5 is completed; the direct method can be: using soil-taking equipment to take the soil at the top of the water-sealing plug, and using analysis equipment to judge the moisture content. Technical personnel in this field can choose according to actual conditions.

[0098] As an example, Figure 2 As shown, an implementable method in step S3 is further provided, and step S3 specifically includes the following steps:

[0099] S30, the water-sealing plug is pressed to separate the pile plug 2 from the pile body 1, that is, the pile plug 2 enters the bearing layer below the pile end under the squeezing and pushing action of the upper filler, and compacts the soil layer below the pile plug 2.

[0100] S31 , adding fillers into the pile body 1 until a preset termination condition is met, wherein, in the S31 stage, i.e., the step of adding fillers into the pile body 1 , a water sealing plug is formed in the pile body 1 .

[0101] In one embodiment, step S31 specifically includes the following steps:

[0102] S310, adding bearing layer reinforcement filler to the pipe pile body 1 until the first preset termination condition is met, wherein one of the first preset termination conditions is that the total volume of the bearing layer reinforcement filler reaches the designed filler volume; one of the first preset termination conditions is that the standard penetration value of the pile end filler meets the designed standard penetration value. In specific implementation, the bearing layer reinforcement filler will form a pile end reinforcement body at the lower part of the insertion end of the pipe pile body 1 to form a good structure.

[0103] The total volume of filler t It can be estimated by the following formula:

[0104]

[0105] In the above formula, The maximum distance between the pile tip and the end of the precast pipe pile; is the volume compression coefficient of the filler.

[0106] It should be pointed out that each time filling is done, a heavy hammer must be lifted out of the hollow of the prefabricated pipe pile and the bearing layer filler must be dropped into the pile end. When reinforcing the filler, the bottom end of the rammer or push drill rod must be kept 5 cm higher than the pile end to ensure the presence of the water-sealing plug.

[0107] In one embodiment, in order to enhance the structural strength of the pile end reinforcement body, an implementable method of step S31 is further provided, specifically: a watertight bag filled with a bearing layer reinforcement filler is put into the pipe pile body 1 until the first preset termination condition is met. In the specific implementation, the bearing layer reinforcement filler is packaged in a watertight bag, which can prevent the bearing layer reinforcement filler from being diluted too quickly after entering the soil layer, resulting in excessive cement loss, thereby solving the problem of low strength of the rammed expansion body.

[0108] Among them, the watertight bag is preferably packaged in an ordinary film plastic bag, or other watertight materials. Those skilled in the art can choose according to actual needs.

[0109] Based on the above embodiment, the components of the bearing layer reinforcement filler include dry hard cement mortar and crushed stone, the mass ratio of dry hard cement mortar and crushed stone is 1:1~1:2.5, and the particle size of the crushed stone is less than or equal to 6 mm; the components of dry hard cement mortar include water, cement and secondary bottom ash from waste incineration, the mass ratio of cement to secondary bottom ash from waste incineration is 1:3~1:5, water, cement and secondary bottom ash from waste incineration are mixed to form dry hard cement mortar, wherein crushed stone is added to provide a transmission skeleton for tamping energy, so that the surrounding soil is easier to be compacted, and the filler is easier to enter the soil, thereby increasing its tamping expansion volume and further improving the bearing performance.

[0110] In one embodiment, due to the structural design of the prefabricated pipe pile, a good transverse extrusion and reinforcement body a can be formed. For example, the extrusion and reinforcement body a is formed by the cooperation of the lifting rope 4 and the pile plug 2 with the extrusion and expansion guide section, the extrusion and reinforcement body a is formed by the cooperation of the lifting rope 4 and the openable pile plug, and the extrusion and reinforcement body a is formed by the bag cap 25, and the soil is formed into a compacted soil body b and an affected soil body c.

[0111] S311, core filling material is added into the pipe pile body 1 until the second preset termination condition is met to obtain the pile foundation structure 6, wherein the second preset termination condition is that the core filling height should be not less than 2m above the pile end; in specific implementation, after the bearing layer reinforcement filler forms a reinforcement body, the core filling filler will fill the remaining hollow of the pipe pile body 1 to ensure the structural strength of the entire pile foundation structure 6.

[0112] In one embodiment, the core filler is concrete with a strength of C30 or above.

[0113] In one embodiment, after the core filling is completed, a heavy hammer is used to tamp or a drill rod is pushed to extrude the core filling concrete, thereby increasing the density of the concrete in the core filling section and enhancing the connection strength between the core filling section and the reinforced bearing layer filler at the pile end.

[0114] In one embodiment, a method for pressing in filler is provided, which utilizes reverse pressing of an auger rig; a continuous feeding filler method is adopted when the auger rig is reversed and pressed in, which is conducive to the filler being subsequently squeezed and expanded toward the pile end through the channel formed by the auger rod and the prefabricated pipe pile.

[0115] An embodiment of the present invention provides a prefabricated pipe pile, which is applied in the above-mentioned prefabricated pipe pile construction method to solve the technical problem of poor water sealing ability in the early filling material reinforcement process in the prior art.

[0116] Please refer to Figures 3 to 11 The present embodiment provides a prefabricated pipe pile, comprising:

[0117] The pipe pile body 1 is hollow;

[0118] A pile plug 2, which is inserted into the end of the pipe pile body 1; the pile plug 2 can be separated from the pipe pile body 1 after being subjected to a preset pressure;

[0119] The sealing member 3 can be elastically clamped between the pile body 1 and the pile plug 2 .

[0120] In this embodiment, the pile plug 2 is inserted into the end of the pipe pile body 1. When the pile plug 2 is inserted into the pipe pile body 1, the sealing member 3 will remain elastically clamped between the pipe pile body 1 and the pile plug 2. The sealing member 3 between the pile plug 2 and the pipe pile body 1 can keep the end of the prefabricated pipe pile with the pile plug 2 sealed; when the pile plug 2 is subjected to a preset pressure, the pile plug 2 will separate from the pipe pile body 1.

[0121] Based on the above embodiment, in a specific construction process, the following steps are included:

[0122] S1, inserting the pile plug 2 into the pipe pile body 1 to form an assembled prefabricated pipe pile, and pressing the assembled prefabricated pipe pile into the soil at a preset depth;

[0123] S2, putting a water-permeable bag filled with high water-stopping filler 5 into the pipe pile body 1, and compacting the water-permeable bag in the pipe pile body 1 to form a water-sealing plug on the pile plug 2, and continue to put in materials and compact until the preset water-stopping conditions are met, wherein the pile plug 2 remains inserted into the pipe pile body 1;

[0124] S3, pressing the water-sealing plug to separate the pile plug 2 from the pile body 1, and adding filler into the pile body 1 until a preset termination condition is met;

[0125] It can be seen from the above process that the pile plug 2 remains inserted into the pipe pile body 1, and the sealing member 3 is elastically clamped between the two, so the pile plug 2 and the pipe pile body 1 can be kept sealed, and it is difficult for pressurized water and soil to enter from between the pile plug 2 and the pipe pile body 1, thereby avoiding the phenomenon of pipe burst; and because a permeable bag with a high water-stop filler 5 is provided, it can absorb water and block the entry of soft mud, thereby avoiding the problem of a soft mud layer inside the pipe pile body 1.

[0126] As an example, Figure 3 , Fig.10 and Fig.11 As shown, a feasible structure of the sealing member 3 is further provided. The sealing member 3 may be a sealing ring. When the sealing member 3 is a sealing ring, a groove for accommodating the sealing ring may be designed on the inner wall of the prefabricated pipe pile or the inner wall of the pile plug 2. After the sealing ring is placed in the groove, the prefabricated pipe pile and the pile plug 2 may clamp the sealing ring to elastically deform it, thereby playing a sealing role. The sealing member 3 may also be a sealing cap. The sealing cap cover is arranged outside the pile plug 2. Then, the structure formed by the sealing cap and the pile plug 2 is inserted into the prefabricated pipe pile together. The sealing cap is elastically deformed under the clamping of the pile plug 2 and the prefabricated pipe pile, thereby playing a sealing role.

[0127] As an example, Figure 3 and Fig.11 As shown, a feasible structure of a prefabricated pipe pile is further provided. The prefabricated pipe pile comprises a pile plug 2 and a pipe pile body 1. The connection mode in which the pile plug 2 can be separated from the pipe pile body 1 under pressure can be that the pile plug 2 and the pipe pile body 1 are connected by friction, that is, the pile plug 2 is embedded in the hollow position of the pipe pile body 1 by friction, and when the pressure on the pile plug 2 is greater than the friction, the pile plug 2 will be separated from the pipe pile body 1; or the pile plug 2 and the pipe pile body 1 are connected by spot welding with a preset connection strength, and when the pressure on the pile plug 2 is greater than the spot welding connection force, the pile plug 2 will be separated from the pipe pile body 1. Other structures that can be separated under pressure can also be selected by those skilled in the art, and no excessive restrictions are made here.

[0128] As an example, in order to solve the technical problem that the lateral expansion effect of the extruded reinforcement body a at the pile end is insufficient, as Figure 3 As shown, the prefabricated pipe pile also includes a plurality of lifting ropes 4; one end of each lifting rope 4 is connected and fixed to the pipe pile body 1 through a lifting ring, and the other end of each lifting rope 4 is connected and fixed to the pile plug 2 through a lifting ring, and the plurality of lifting ropes 4 are arranged around the center of the pile plug 2.

[0129] Specifically, when step S3 is implemented, when the pile plug 2 is separated from the pipe pile body 1, the pile plug 2 will be suspended at the lower part of the insertion end of the pipe pile body 1; when fillers are added to the pipe pile body 1, the pile plug 2 will move downward and compress the soil layer below the pile plug 2. When the fillers filled in the bottom of the prefabricated pipe pile reach a certain volume, the bearing layer soil layer below the pile plug 2 is fully compressed, and the supporting pile plug 2 no longer moves downward; if the strength of the reinforced bearing layer soil is low, the pile plug 2 is restricted from continuing to move downward after reaching the maximum length of the suspension rope, and the subsequent filled fillers form a nearly spherical filler extrusion and reinforcement body a with a transverse diameter greater than the diameter of the prefabricated pipe pile at the lower part of the prefabricated pipe pile end. At the outer edge of the extrusion and reinforcement body a, the bearing layer soil is subjected to stress waves or extrusion to form a larger volume and a compacted soil b and an affected soil c with a compression modulus higher than the original bearing layer soil.

[0130] From the above, it can be seen that the presence of the lifting rope 4 can prevent the pile plug 2 from moving downward without restriction. In the scenario of water-rich soft soil, the lifting rope 4 cooperates with the pile plug 2 to enable the filler to form an extruded and reinforced body a, a compacted soil body b and an affected soil body c at the bottom of the prefabricated pipe pile, thereby ensuring the strength of the entire pile foundation structure 6.

[0131] In one embodiment, the suspension rope 4 is a corrosion-resistant and high-strength steel wire rope, and the material can be selected according to the characteristics of the bearing layer. The length of the suspension rope 4 can control the maximum distance S between the pile plug 2 and the end of the precast pipe pile, which can be selected according to the properties of the bearing layer soil. The following provides a method: for saturated silt and clay bearing layers with standard penetration values Nk of 5 < Nk ≤ 10, 10 < Nk ≤ 15, and Nk > 15 respectively, the values of the maximum distance S are 2.5D to 3D, 2D to 2.5D, and 1.5D to 2D respectively, where D is the diameter of the precast pipe pile.

[0132] Based on the above embodiment of the suspension rope 4, in one embodiment, as Figure 3 shown, in order to improve the lateral extrusion effect, a realizable structure of the pile plug 2 is further provided. The pile plug 2 has an extrusion guiding section. Along the direction from the pipe pile body 1 to the pile plug 2, the pile diameter of the extrusion guiding section gradually increases, that is, the surface axis formed by the extrusion guiding section forms a certain angle with the axis of the pipe pile body 1. Specifically, when step S3 is implemented, after the pile plug 2 is separated from the pipe pile body 1, filler is put into the pipe pile body 1. Due to the existence of the suspension rope 4, the extrusion guiding section of the pile plug 2 can guide the filler to move to both sides of the pile plug 2, which can greatly promote the filling of the filler to both sides of the pile end. As the filler is added, the filler continuously squeezes into both sides under the guidance of the conical extrusion guiding section, strengthening the soil on the side of the pile, and forming an extrusion reinforcement body a whose volume is several times that of the diameter of the precast pipe pile, significantly improving the bearing capacity of the end of the precast pipe pile in the water-rich soft soil layer.

[0133] Further, in one embodiment, as Figure 3 shown, in order to better improve the effect of the lateral extrusion effect, a specific implementation structure of the pile plug 2 is provided. Along the direction from the pipe pile body 1 to the pile plug 2, the pile plug 2 sequentially includes an upper extrusion guiding section 20, a stepped section 21, a lower extrusion guiding section 22, and a constant diameter section. The maximum pile diameter of the upper extrusion guiding section 20 is less than or equal to the minimum pile diameter of the lower extrusion guiding section 22, and the pile diameter of the upper extrusion guiding section 20 is slightly smaller than the inner hollow diameter of the pipe pile body 1. The stepped section 21 includes a narrow-diameter stepped section and a wide-diameter stepped section. The narrow-diameter stepped section and the wide-diameter stepped section form a step that is clamped to the bottom of the pipe pile body 1. The narrow-diameter stepped section is inserted into the pipe pile body 1, and the wide-diameter stepped section abuts against the bottom of the pipe pile body 1. The stepped section 21 is used to clamp the pile plug 2 on the pipe pile body 1, that is, to embed the upper extrusion guiding section 20 into the pipe pile body 1 and clamp the wide-diameter stepped section outside the pipe pile body 1. Specifically, when step S3 is implemented, after the pile plug 2 is separated from the pipe pile body 1, the upper extrusion guiding section 20 is located at the top of the pile plug 2, and the filler just coming down from the precast pipe pile can be initially guided to both sides, avoiding the accumulation of materials at the top of the pile plug 2. And the lower extrusion guiding section 22 can secondarily guide the moving direction of the filler, making the lateral expansion area of the extrusion reinforcement body a larger.

[0134] In one embodiment, as Fig.10 As shown, the pile plug 2 may adopt a sealing ring or a sealing cap, as long as the sealing ability of the pile plug 2 and the pile body 1 is guaranteed when the pile plug 2 is inserted into the pile body 1.

[0135] Furthermore, in one embodiment, if Figures 4 to 9 As shown, in order to better improve the effect of the lateral squeezing and expanding effect, a specific implementation structure of the pile plug 2 is provided. The pile plug 2 includes a connecting seat 23 and at least three pile petals 24. The plurality of pile petals 24 are arranged on the peripheral side of the connecting seat 23. The pile petals 24 are hinged to the connecting seat 23. The plurality of pile petals 24 can be turned over to surround the connecting seat 23 or can be turned over and unfolded to form an open and closable pile plug. Specifically, when step S3 is implemented, after the pile plug 2 is separated from the pile body 1, the pile plug 2 will be turned over from the original state of surrounding the connecting seat 23 to the unfolded state under the squeezing and pushing action of the upper part, forming a petal-like structure. The outer contour diameter of the unfolded pile plug 2 is much larger than the diameter of the prefabricated pipe pile, which can greatly improve the lateral filler guiding ability of the pile plug 2, and form a nearly spherical filler extrusion expansion body with a diameter several times the diameter of the prefabricated pipe pile at the pile end of the prefabricated pipe pile.

[0136] It should be noted that the different positions of the pile petal 24 and the connecting seat 23 will make the pile plug 2 into an upper hinged opening and closing pile plug (such as Figures 4 to 7 ) and the lower hinged opening and closing pile plug (as shown Figures 8 to 9 There are two types of pile plugs (as shown in the figure), an upper hinged lobed pile plug is provided with an hinged arm at the top end of the pile plug 2, a pin hole is provided in the hinged arm, a lifting ring is provided on the outer wall of the upper and middle sections of the upper hinged lobed pile plug, the upper hinged lobed pile plug is connected with a double cross hinged seat through the hinged arm, and is combined into an upper hinged opening and closing type pile plug; a lower hinged lobed pile plug is provided with an hinged arm at the bottom end of the pile plug 2, a pin hole is provided in the hinged arm, the lower hinged lobed pile plug is connected with a double cross hinged seat through the hinged arm, and is combined into a lower hinged opening and closing type pile plug.

[0137] In one embodiment, if Figures 4 to 7 As shown, the pile plug 2 is an upper hinged openable pile plug, and the lifting ring of the pile plug 2 of the upper hinged openable pile plug is connected to the prefabricated pipe pile by a lifting rope 4. The upper end of the upper hinged petal pile plug is provided with an embedding step with an outer diameter slightly smaller than the inner diameter of the prefabricated pipe pile, which is used for the openable pile plug to be embedded in the inner hole of the prefabricated pipe pile to realize the installation of the openable pile plug on the pile end of the prefabricated pipe pile. Specifically, when step S3 is implemented, after the pile plug 2 is separated from the pipe pile body 1, due to the limiting effect of the lifting rope 4, the lower end of the petal pile plug will open outwards under the upper squeezing and pushing effect and the limiting effect of the lifting rope 4 of the upper hinged openable pile plug, and finally a petal-shaped pile plug 2 with an outer diameter several times larger than the prefabricated pipe pile is formed at a certain distance from the bottom of the prefabricated pipe pile.

[0138] In one embodiment, if Figures 8 to 9As shown, the pile plug 2 is a lower hinged opening and closing type pile plug, which does not need to be connected to the pipe pile body 1 through the lifting rope 4. The upper end of the lower hinged petal pile plug is provided with an embedding step whose outer diameter is slightly smaller than the inner diameter of the prefabricated pipe pile, which is used for the opening and closing type pile plug to be embedded in the inner hole of the prefabricated pipe pile to realize the installation of the opening and closing type pile plug on the pile end of the prefabricated pipe pile. Specifically, when step S3 is implemented, after the pile plug 2 is separated from the pipe pile body 1, the pile plug 2 is completely separated from the pipe pile body 1. Due to the squeezing action of the upper part, the petal pile plug opens outward from the upper end, and finally forms a petal-like structure.

[0139] It should be pointed out that the lower hinged opening and closing pile plug does not have the limiting effect of the lifting rope 4, and its pressing depth is mainly determined by the properties of the soil layer at the bottom of the pile, which can effectively make up for the defect of insufficient reinforcement of the bearing layer directly below the upper hinged opening and closing pile plug caused by the design. Of course, technical personnel in this field can make corresponding choices and connect the lower hinged opening and closing pile plug with the lifting rope 4, retaining the defect of insufficient reinforcement of the bearing layer directly below the upper hinged opening and closing pile plug. Technical personnel in this field can make choices according to actual needs.

[0140] In one embodiment, along the direction from the pile body 1 to the pile plug 2 on the pile petals 24, the pile petals 24 include a narrow-diameter pile segment, an extrusion guide segment and a constant-diameter pile segment in sequence. Specifically, when step S3 is implemented, the extrusion guide segment cooperates with the petal-shaped structure to greatly increase the overall volume of the extrusion reinforcement body a.

[0141] In one embodiment, the pile plug 2 using the pile petal 24 can choose to use a sealing cap as the sealing member 3, that is, when the pile plug 2 is inserted into the pile body 1, the sealing cap is covered on the pile plug 2, and the brim of the sealing cap is elastically clamped between the pile plug 2 and the pile body 1.

[0142] As an example, in order to solve the technical problem of insufficient lateral expansion effect of pile end reinforcement, such as Fig.11 As shown, the prefabricated pipe pile also includes a bag cap 25; the bag cap 25 includes a cap body and a brim; a circle of brim is connected to the circumference of the cap body; the cap body is covered above the pile plug 2, and the brim is connected and fixed to the pipe pile body 1, wherein the pile plug 2 and the pipe pile body 1 are connected by 2-3 spot weldings, and the welding strength is such that the bottom pile plug 2 will not fall off under the action of gravity.

[0143] Specifically, when step S2 is implemented, the bagged high water-stop filler 5 will form a water-sealing plug on the bag cap 25. When step S3 is implemented, the bag cap 25 will squeeze the pile plug 2 out of the pile body 1, and form a spherical extrusion and reinforcement body a, compacted soil b and affected soil c under the pile body 1.

[0144] From the above, it can be seen that the bag cap 25 can form a spherical extrusion reinforcement body a under the pile body 1 without the need for a lifting rope 4, which can solve the problem of insufficient lateral extrusion effect of the pile end reinforcement body. Compared with the lifting rope 4 solution, the proposed bag cap 25 solution can effectively solve the construction of prefabricated pipe pile end filler reinforcement in high water pressure and thick silt distribution bearing layer. On the one hand, it ensures the effectiveness and continuity of water sealing in the reinforcement stage; on the other hand, the limitation of the bag can well form a nearly spherical filler reinforcement body.

[0145] It should be noted that after the bladder cap 25 is used, the high water-stop filler 5 added in step S2 can be replaced with a high-strength concrete filler, and the strength of the pile end reinforcement can be guaranteed. Those skilled in the art can make a choice according to actual needs.

[0146] In addition, when using the bag method for reinforcement, it is advisable to use non-ramming methods to reinforce the filler; when the ramming method must be used, the filler should be filled first, and then low-energy ramming should be performed to avoid the rammer directly hitting the bag.

[0147] In one embodiment, if Fig.11 As shown, the opening end of the bag cap 25 is provided with an annular fixing ring of the bag cap 25, and circular holes corresponding to the threaded holes of the prefabricated pipe pile end plate are evenly distributed in the annular fixing ring of the bag cap 25. The annular fixing ring of the bag cap 25 is fixed to the prefabricated pipe pile end plate by fastening screws. After the bag is folded, it is placed in the hollow of the bottom of the prefabricated pipe pile. A pile plug 2 is installed under the bag cap 25, and a gap is provided at the radially overlapping portion of the pile plug 2 and the annular fixing ring of the bag. A sealing ring is provided in the gap between the pile plug 2 and the prefabricated pipe pile, and the sealing ring is elastically clamped by the pile plug 2 and the prefabricated pipe pile.

[0148] In one embodiment, the pouch cap 25 is a spherical open-bag structure when unfolded, and the pouch is made of a membrane-like organic material or inorganic material, and can be made of a high-strength material with reinforcement inside the pouch cap 25 to make it easy to deform.

[0149] To summarize the above-mentioned prefabricated pipe piles, the similarities of the above-mentioned prefabricated pipe piles are that, first, the pile plug 2 and the pipe pile body 1 are both provided with a seal 3, which can play a sealing and waterproofing role, and second, their purpose is to form an extruded and reinforced body a with a sufficiently large lateral volume below the pipe pile body 1; the difference is that the specific structure of the extruded and reinforced body a is different, at least there are examples of the extruded and reinforced body a formed by the cooperation of the lifting rope 4 and the pile plug 2 with an extrusion guide section, the extruded and reinforced body a formed by the cooperation of the lifting rope 4 and the opening and closing pile plug, and the extruded and reinforced body a formed by the bag cap 25. It can be seen that the present scheme provides a large number of prefabricated pipe piles that can perform the prefabricated pipe pile construction method, and the content is very detailed. Those skilled in the art can choose according to actual needs.

[0150] The embodiment of the present invention provides a pile foundation structure 6, such as Fig.12and Fig.13 As shown, according to the above-mentioned prefabricated pipe pile construction method, the above-mentioned prefabricated pipe pile is constructed to obtain a pile foundation structure 6, wherein Fig.12 The pile foundation structure 6 shown is a pile foundation structure 6 including a suspension rope. Fig.13 The pile foundation structure 6 shown is a pile foundation structure 6 including a bladder cap 25 .

[0151] The formed pile foundation structure 6 has the following advantages: on the one hand, during the early filling process, the cooperation of the bagged high-water-stop filler 5, the water-sealing plug and the seal 3 can effectively prevent water or soft mud layer from entering the prefabricated pipe piles, thereby ensuring the water-sealing ability of the pile bottom reinforcement process and improving the quality of the reinforcement body; on the other hand, due to the design structure of the prefabricated pipe pile, an extruded reinforcement body a with a sufficiently large lateral volume can be formed under the pipe pile body 1, ensuring sufficient lateral extrusion and expansion effect, thereby improving the bearing capacity of the pile end reinforcement piles of small and medium diameter prefabricated pipe piles.

[0152] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0153] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are merely 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.

Claims

1. A prefabricated pipe pile construction method, characterized in that: The following steps are involved: Inserting a pile plug into the end of a hollow pipe pile body to form a prefabricated pipe pile, and pressing the prefabricated pipe pile into the soil at a preset depth; Putting a water-permeable bag filled with high water-stopping filler into the pipe pile body, and compacting the water-permeable bag in the pipe pile body to form a water-sealing plug on the pile plug, and continuing to put in materials and compact until the preset water-stopping conditions are met, wherein the pile plug remains inserted into the pipe pile body; The water sealing plug is pressed to separate the pile plug from the pipe pile body, and filler is added into the pipe pile body until a preset termination condition is met.

2. The prefabricated pipe pile construction method according to claim 1, characterized in that: The components of the high water-stop filler include dry quicklime, dry waste incineration secondary bottom slag fine sand, and a mixture of dry cement and waste incineration secondary bottom slag fine sand; The method of placing high water-stop filler into a permeable bag comprises the following steps: First, the quicklime is filled into the water permeable bag; Then, the waste incineration secondary bottom ash fine sand is filled into the water permeable bag; Finally, the mixture of the cement and the fine sand of the secondary bottom ash from waste incineration is filled into the water-permeable bag.

3. The prefabricated pipe pile construction method according to claim 2, characterized in that: The volume of the quicklime is 1 / 10 to 1 / 6 of the volume of the permeable bag; The volume of the fine sand from the secondary bottom ash of garbage incineration is 1 / 3 to 1 / 2 of the volume of the permeable bag; The volume of the mixture of the cement and the fine sand from the secondary bottom ash of waste incineration is 1 / 3 to 1 / 2 of the volume of the permeable bag, and the mass ratio of the cement to the fine sand from the secondary bottom ash of waste incineration in the mixture is 1:3 to 1:

5.

4. The prefabricated pipe pile construction method according to claim 1, characterized in that: In the step of placing the water-permeable bag filled with high water-stop filler into the pipe pile body, the outer peripheral side surface of a single water-permeable bag abuts against the inner peripheral wall of the pipe pile body.

5. The prefabricated pipe pile construction method according to claim 1, characterized in that: The water-permeable bag is a woven mesh bag.

6. The prefabricated pipe pile construction method according to claim 1, characterized in that: The height of the water sealing plug is 5cm-30cm.

7. The prefabricated pipe pile construction method according to claim 1, characterized in that: The preset water-stopping condition is that the water content at the top of the water-sealing plug is less than a preset value.

8. The prefabricated pipe pile construction method according to claim 1, characterized in that: Filling is added to the pile body until a preset termination condition is met. Specifically, in this step: Adding bearing layer reinforcement filler into the pipe pile body until a first preset termination condition is met; A core filling material is added into the pipe pile body until a second preset termination condition is met.

9. The prefabricated pipe pile construction method according to claim 8, characterized in that: In the step of adding a bearing layer reinforcement filler into the pipe pile body until the first preset termination condition is met, the specific steps are as follows: A watertight bag filled with a bearing layer reinforcement filler is put into the pipe pile body until the first preset termination condition is met.

10. The prefabricated pipe pile construction method according to claim 9, characterized in that: The components of the bearing layer reinforcement filler include dry hard cement mortar and crushed stone, the mass ratio of the dry hard cement mortar to the crushed stone is 1:1-1:2.5, and the particle size of the crushed stone is less than or equal to 6 mm; The components of the dry hard cement mortar include water, cement and secondary bottom ash from waste incineration, and the mass ratio of the cement to the secondary bottom ash from waste incineration is 1:3-1:

5.

11. A prefabricated pipe pile, characterized in that: The method for constructing a prefabricated pipe pile according to any one of claims 1 to 10 comprises a hollow pipe pile body, a pile plug and a sealing member; The pile plug is inserted into the end of the pipe pile body; the pile plug can be separated from the pipe pile body after being subjected to a preset pressure; The sealing member can be elastically clamped between the pipe pile body and the pile plug.

12. The prefabricated pipe pile according to claim 11, characterized in that: The prefabricated pipe pile also includes a plurality of hanging ropes; One end of the lifting rope is connected and fixed to the pipe pile body, and the other end of the lifting rope is connected and fixed to the pile plug.

13. The prefabricated pipe pile according to claim 12, characterized in that: The pile plug has an extrusion and expansion guide section, and the pile diameter of the extrusion and expansion guide section gradually increases along the direction from the pipe pile body to the pile plug.

14. The prefabricated pipe pile according to claim 13, characterized in that: Along the direction from the pipe pile body to the pile plug, the pile plug comprises an upper extrusion and expansion guide section, a platform section and a lower extrusion and expansion guide section in sequence; The maximum pile diameter of the upper extrusion and expansion guide section is less than or equal to the minimum pile diameter of the lower extrusion and expansion guide section; The stage is used to clamp the pile plug onto the pipe pile body.

15. The prefabricated pipe pile according to claim 11 or 12, characterized in that: The pile plug comprises a connection seat and a plurality of pile petals, wherein the plurality of pile petals are arranged on the peripheral side of the connection seat, the pile petals are hinged to the connection seat, and the plurality of pile petals can be turned over to surround the connection seat or can be turned over to unfold.

16. The prefabricated pipe pile according to claim 11, characterized in that: The prefabricated pipe pile also includes a bag cap; The pouch cap comprises a cap body and a brim; The circumference of the cap body is connected with a circle of the cap brim; The cap body is arranged above the pile plug, and the cap brim is connected and fixed to the pipe pile body.

17. A pile foundation structure, characterized in that: The prefabricated pipe piles described in any one of claims 11 to 16 are applied to the prefabricated pipe pile construction method described in any one of claims 1 to 10 for construction.

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