Construction method of wedge-shaped composite discrete material pile

Abstract

The invention relates to the technical field of discrete material pile construction, and discloses a construction method of a wedge-shaped composite discrete material pile, which comprises the following steps: S1, piling operation preparation; s2, along-rail gooseneck type rod hammers are used for ramming and reaming, and gravel is mixed with soil to form a retaining wall; s3, pile forming at the lower part; s4, forming a pile in the middle; s5, molding the upper pile body; s6, pile forming of the upper pile body; s7, pile top forming; and S8, a complete wedge-shaped discrete material pile body is formed. The wedge-shaped pile body with the large upper portion and the small lower portion is formed, the upper portion load pressure stress trapezoid transmission characteristic is formed, the pressure bearing area of the pile top is increased, meanwhile, the compactness and the compressive strength of soil between piles are promoted to be improved, the lateral restraining force generated by the discrete material pile body is promoted to be improved, and the multiple effects of synchronous improvement are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of bulk material pile construction, and in particular to a construction method of a wedge-shaped composite bulk material pile. Background Art

[0002] Bulk piles are made of bulk materials and do not condense. When a certain bearing capacity is reached, they will spread out in all directions. They are not as self-contained as concrete piles and wooden piles. The single pile bearing capacity of bulk piles (i.e., the strength and stability of the foundation soil and the pile itself can be guaranteed under load, and the deformation is within the allowable range to ensure the maximum load that the structure can withstand in normal use) is mainly determined by the lateral constraint of the soil around the pile. If the soil between the piles is loose, weak, and low in strength, and has not been reinforced accordingly, the single pile bearing capacity will be very small, and the waste of resources will be very large. However, traditional pile-making processes have basically ignored this point. Therefore, the market is in urgent need of:

[0003] 1. When constructing the pile body, the soil between the piles needs to be reinforced accordingly to increase the lateral restraint force of the soil between the piles;

[0004] 2. Increase the bottom depth of the pile: place the bottom of the pile at a deeper elevation to obtain a greater treatment or penetration depth;

[0005] 3. Improve the strength of the bearing layer at the bottom of the pile: Under the tamping action, the hard aggregate replacement body is rammed into the soil at the pile end to increase the pile end resistance and pile bearing capacity.

[0006] In view of this, we propose a construction method for wedge-shaped composite granular material piles. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a construction method for wedge-shaped composite granular material piles.

[0008] In order to solve the above technical problems, the technical solution of the present invention is:

[0009] A construction method for a wedge-shaped composite granular material pile, characterized in that it comprises the following steps:

[0010] S1. Stop the construction equipment at the construction area, align the gooseneck hammer of the pile driver with the pile position to prepare for the piling operation;

[0011] S2. Micro-hole expansion: The gooseneck hammer along the track tamps the soil from top to bottom. The downward impact of the gooseneck hammer along the track crushes the stones. The crushed stones squeeze the soil laterally. The soil and crushed stones on the side are mixed more and more densely due to the squeezing, thereby forming a complete and solid protective wall of the pile hole. At the same time, due to the lateral connection between the top of the gooseneck hammer along the track and the pile driver track, a flexible connection is achieved through the "universal joint", forming a "gooseneck" function; during the injection process, especially when the bottom of the hammer touches a large-diameter stone or hard object, the upper end of the gooseneck hammer along the track will naturally produce a certain degree of micro-swing (front and back or left and right), and the "universal joint" effect can leave a certain amount of activity space for this swing, forming a flexible connection effect, so that it can not only eliminate the adverse factors caused by the rigid connection between the original pile driver track and the gooseneck hammer along the track (causing hard collision with the pile driver track and corresponding distortion and damage), but also can achieve a certain degree of micro-hole expansion effect from bottom to top on the pile hole, forming a complete and continuous wedge-shaped pile hole;

[0012] S3, lower pile formation: after the pile hole and stable retaining wall are formed, the replacement material is filled in sections from bottom to top, and the hammer head is replaced for section-by-section tamping to ensure that each section of the lower pile body reaches the vertical compaction of the pile body and the lateral extrusion of the hole wall, so that the pile body and the retaining wall form a tightly combined vertical bearing body; at the same time, a wedge-shaped replacement material lower pile body with a diameter gradually increasing from bottom to top is formed;

[0013] S4, middle pile formation: fill the pile hole with replacement material in sections from bottom to top, and tamp it in sections at the same time, to ensure that each section of the middle pile body reaches the vertical compaction of the pile body and the lateral extrusion of the hole wall, so that the pile body and the retaining wall form a tightly combined vertical bearing body; at the same time, a wedge-shaped replacement material middle pile body with a diameter gradually increasing from bottom to top is formed;

[0014] S5, upper pile body mold: after the lower and middle pile bodies are formed, the replacement material is continued to be backfilled in the pile hole, and then the flat cone long neck middle hammer is replaced for continuous tamping, and the middle and lower wedge-shaped pile bodies are further tamped, compacted and expanded by the tamping force transmission, and at the same time, the upper wedge-shaped pile body mold with a larger upper part and a smaller lower part is formed;

[0015] S6, forming the upper pile body: the inner cavity of the outer mold of the wedge-shaped pile body formed by the operation in S5 is filled with replacement material; the outer mold of the wedge-shaped pile body backfilled with replacement material in S5 and the replacement material in the mold are continuously rammed with a flat cone flat hammer, and the ramming is stopped after the hammer withdrawal standard is reached, forming a wedge-shaped pile body of the upper part of the replacement material that gradually expands from bottom to top, and at the same time forming an expanded outer mold (ramming pit) at the top of the pile body;

[0016] S7, forming the pile top: filling the outer mold at the top of the pile body with replacement material, and continuing to compact it with a flat cone hammer to form a wedge-shaped expanded diameter pile body at the top;

[0017] S8. The wedge-shaped composite bulk material pile is constructed through the above steps to form a complete and continuous wedge-shaped composite bulk material pile body, which is composed of multiple sections of pile bodies with different diameters and shapes stacked on the same vertical line, and the pile body with a diameter gradually increasing from bottom to top is tightly integrated with the retaining wall.

[0018] Preferably, the diameter, mass and height of the gooseneck hammer along the track in S2 are configured accordingly according to different design requirements, thickness of soft soil layer or burial depth, so as to meet the hole depth and pile specifications required by the design; at the same time, through a simple connection method, the length, weight or diameter of the hammer body can be increased or decreased (increased or decreased) at will according to the needs of different formation conditions, so as to obtain a one-hammer-multiple-purpose effect to adapt to various geological conditions and design requirements.

[0019] Preferably, the length of the along-track gooseneck hammer, flat-cone long-necked middle hammer, and flat-cone flat hammer in S2 needs to be slightly longer than the thickness of the soft soil layer or the burial depth, so that the hammer handles on the top of the along-track gooseneck hammer, flat-cone long-necked middle hammer, and flat-cone flat hammer can always be exposed from the floor surface, which is conducive to the automatic connection between the hanging ear and the hammer body and improves the construction efficiency; at the same time, the burial depth of each hammer body can be intuitively understood, which is convenient for construction records and improving the quality control effect and efficiency.

[0020] Preferably, the replacement material in S3 is a bulk material with a particle size not too large, such as crushed stone soil, sandy soil, construction waste aggregate, industrial waste aggregate, etc., and cementitious material can be added when there are special design requirements.

[0021] Preferably, the solid protective wall formed by the mixture of soil and gravel in S2 provides peripheral support and restraint for the replacement material during compaction, limiting the displacement material from being squeezed and expanded around due to high-energy tamping impact, thereby improving the efficiency, effect and density of the pile.

[0022] Preferably, the on-track gooseneck hammer top flexible connection pile driver in S2 is mainly to set one or more universal joints on the top of the on-track gooseneck hammer to achieve the "gooseneck" function that the hammer body rests on the hard bottom without tilting and the top can swing freely.

[0023] Preferably, the track-following gooseneck hammer in S2 includes two types of hammer heads: a stone-breaking and stone-extruding type with a pointed cone side extrusion shape at the bottom and a vertical extrusion shape for cutting, and a compacting and compacting type with a flat bottom, as well as a "pin-type connecting device" that can be quickly disassembled and assembled.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] ①During the construction of the pile body, since it is a bulk material pile, in view of the bulk characteristics of the bulk material pile, during the construction, through the repeated tamping of the gooseneck hammer along the track, the stones are crushed and squeezed to the side of the pile to mix with the soil to form a protective wall for the pile hole, and at the same time, a certain restricted area is formed for the bulk backfill material to be filled, solving the problem of scattering caused by impact around the bulk material during the pile forming process;

[0026] ② The top of the gooseneck hammer used in the construction is flexibly connected to the pile driver, which avoids the problem of the gooseneck hammer and the pile driver body being fixedly connected and swinging and deviating when encountering hard stones during the construction process, causing the pile driver to be twisted and damaged;

[0027] ③ The flexible connection between the top of the gooseneck hammer and the pile driver also brings about the unexpected effect of micro-expansion of the pile hole during lateral swing during construction, which increases the diameter of the pile hole and the pile body, facilitates the up and down movement of the hammer body, and improves construction efficiency.

[0028] ④ The increase in hole diameter can increase the bottoming depth of the pile body (reduce frictional resistance): placing the pile bottom at a deeper elevation to obtain a greater treatment or penetration depth to bring unexpected effects;

[0029] ⑤ Under the tamping action during pile formation, a wedge-shaped pile body with a larger top and a smaller bottom is further formed to adapt to the transmission characteristics of the upper load compressive stress, that is, to achieve:

[0030] a. For piles that bear vertical pressure, the compressive stress will gradually decrease as the depth of the pile increases. The pile section that bears the greatest pressure is at the upper part of the pile (the top of the pile). By intentionally making the pile into a wedge shape, you can achieve twice the result with half the effort.

[0031] b. For bulk material piles, under the action of lateral constraints (soil-rock retaining wall confining pressure), the piles will become denser and denser, and the compressive strength will gradually increase;

[0032] c. The wedge-shaped pile body makes the soil between the piles denser and denser, and at the same time, the restraining effect on the pile body becomes stronger;

[0033] It has a dual effect: it simultaneously promotes the further improvement of the compressive strength of the soil between the piles and the lateral restraint force on the pile body. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the construction process of the present invention;

[0035] Figure 2 It is a schematic diagram of the structure of the wedge-shaped composite granular material pile in the present invention;

[0036] Figure 3 Schematic diagram of the pointed cone shape of the wedge-shaped composite granular material pile in the present invention;

[0037] Figure 4 It is a cross-sectional view of the wedge-shaped composite granular material pile taken along line AA in the present invention;

[0038] Figure 5 It is a cross-sectional view of a wedge-shaped composite bulk material pile BB in the present invention;

[0039] Figure 6 It is a cross-sectional view of a wedge-shaped composite granular material pile CC in the present invention;

[0040] Figure 7 It is a schematic diagram of compressive stress transmission of a wedge-shaped composite granular material pile in the present invention;

[0041] Figure 8 It is a schematic diagram of the structure of the gooseneck hammer along the track and the single cone side extrusion stone breaking hammer head in the present invention;

[0042] Fig. 9 It is a schematic diagram of the structure of the gooseneck hammer along the track and the multi-cone cutting stone breaking hammer head in the present invention;

[0043] Fig.10 It is a schematic diagram of the structure of the gooseneck type hammer for compaction and compaction (compacting and compacting hammer head) along the track in the present invention;

[0044] Fig.11 This is a schematic diagram of the flat cone long neck middle hammer structure of the present invention;

[0045] Fig.12 It is a schematic diagram of the flat cone flat hammer structure in the present invention;

[0046] Fig.13 The figure is a comparison chart of the bearing capacity of pile bodies formed by the construction method of the present invention and the existing combination hammer construction method. DETAILED DESCRIPTION

[0047] The specific embodiments of the present invention are further described below. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0048] Give a brief but clear description of the core technical problems to be solved by this application, the technical solutions to be used to solve the core technical problems, and the technical effects that can be achieved.

[0049] Example

[0050] like Figure 1-12 As shown, the present invention provides a construction method for a wedge-shaped composite granular material pile, which is characterized by comprising the following steps:

[0051] S1. Stop the construction equipment at the construction area, align the gooseneck hammer of the pile driver with the pile position to prepare for the piling operation;

[0052] S2. Micro-hole expansion: The gooseneck hammer along the track tamps the soil from top to bottom. The downward impact of the gooseneck hammer along the track crushes the stones. The crushed stones squeeze the soil laterally. The soil and crushed stones on the side are mixed more and more densely due to the squeezing, thereby forming a complete and solid protective wall of the pile hole. At the same time, due to the lateral connection between the top of the gooseneck hammer along the track and the pile driver track, a flexible connection is achieved through the "universal joint", forming a "gooseneck" function; during the injection process, especially when the bottom of the hammer touches a large-diameter stone or hard object, the upper end of the gooseneck hammer along the track will naturally produce a certain degree of micro-swing (front and back or left and right), and the "universal joint" can leave a certain amount of activity space for this swing, forming a gooseneck function and achieving a flexible connection effect, so that it can not only eliminate the adverse factors caused by the rigid connection between the original pile driver track and the gooseneck hammer along the track (causing hard collision with the pile driver track and corresponding distortion and damage), but also can achieve a certain degree of micro-hole expansion effect from bottom to top on the pile hole, forming a complete and continuous wedge-shaped pile hole;

[0053] S3, lower pile formation: after the pile hole and stable retaining wall are formed, the replacement material is filled in sections from bottom to top, and the hammer head is replaced for section-by-section tamping to ensure that each section of the lower pile body reaches the vertical compaction of the pile body and the lateral extrusion of the hole wall, so that the pile body and the retaining wall form a tightly combined vertical bearing body; at the same time, a wedge-shaped replacement material lower pile body with a diameter gradually increasing from bottom to top is formed;

[0054] S4, middle pile formation: fill the pile hole with replacement material in sections from bottom to top, and tamp it in sections at the same time, to ensure that each section of the middle pile body reaches the vertical compaction of the pile body and the lateral extrusion of the hole wall, so that the pile body and the retaining wall form a tightly combined vertical bearing body; at the same time, a wedge-shaped replacement material middle pile body with a diameter gradually increasing from bottom to top is formed;

[0055] S5, upper pile body mold: after the lower and middle pile bodies are formed, the replacement material is continued to be backfilled in the pile hole, and then the flat cone long neck middle hammer is replaced for continuous tamping, and the middle and lower wedge-shaped pile bodies are further tamped, compacted and expanded by the tamping force transmission, and at the same time, the upper wedge-shaped pile body mold with a larger upper part and a smaller lower part is formed;

[0056] S6, forming the upper pile body: the inner cavity of the outer mold of the wedge-shaped pile body formed by the operation in S5 is filled with replacement material; the outer mold of the wedge-shaped pile body backfilled with replacement material in S5 and the replacement material in the mold are continuously rammed with a flat cone flat hammer, and the ramming is stopped after the hammer withdrawal standard is reached, forming a wedge-shaped pile body of the upper part of the replacement material that gradually expands from bottom to top, and at the same time forming an expanded outer mold (ramming pit) at the top of the pile body;

[0057] S7, forming the pile top: filling the outer mold at the top of the pile body with replacement material, and continuing to compact it with a flat cone hammer to form a wedge-shaped expanded diameter pile body at the top;

[0058] S8. The wedge-shaped composite bulk material pile is constructed through the above steps to form a complete and continuous wedge-shaped composite bulk material pile body, which is composed of multiple sections of pile bodies with different diameters and shapes stacked on the same vertical line, and the pile body with a diameter gradually increasing from bottom to top is tightly integrated with the retaining wall.

[0059] In this embodiment, the diameter, mass and height of the gooseneck hammer along the track in S2 are configured according to different design requirements, thickness of soft soil layer or burial depth to meet the design requirements of hole depth and pile specifications; at the same time, a simple connection method is used to increase or decrease (increase or decrease) the length or weight or diameter of the hammer body according to the needs of different formation conditions, so as to obtain a one-hammer multi-purpose effect to adapt to various geological conditions and design requirements.

[0060] In this embodiment, the length of the gooseneck hammer, flat cone long neck middle hammer and flat cone flat hammer in S2 needs to be slightly longer than the thickness of the soft soil layer or the burial depth, so that the hammer handles on the top of the gooseneck hammer, flat cone long neck middle hammer and flat cone flat hammer can always be exposed from the floor surface, which is conducive to the automatic connection between the hanging ear and the hammer body and improves the construction efficiency; at the same time, the depth of each hammer body into the soil can be intuitively understood, which is convenient for construction records and improving the quality control effect and efficiency.

[0061] In this embodiment, the replacement material in S3 is a bulk material such as crushed stone soil, sand, construction waste aggregate, industrial waste aggregate, etc., the particle size of which should not be too large. Cementitious materials can be added when there are special design requirements.

[0062] In this embodiment, the solid protective wall formed by the mixture of soil and gravel in S2 provides peripheral support and restraint for the replacement material during the compaction process, limiting the unlimited squeezing and expansion of the replacement material around due to the impact of high-energy tamping, thereby improving the efficiency, effect and density of the pile.

[0063] It is worth further explaining that after strong compaction, the bulk material is replaced, and a large amount of filler is mixed with the soil between the piers during the formation of the pile body. The shallower the area, the more the mixture. Therefore, the soil between the piers is no longer the original soil but a mixed soil with much improved water content and density. It can form a composite foundation together with the pile body. After the soil between the piers is compacted by the compressive stress tendency, it also has a direct effect of increasing the confining pressure on the constraint force of the pile body.

[0064] In this embodiment, the flexible connection pile driver at the top of the gooseneck hammer along the track in S2 is mainly to set one or more universal joints at the top of the gooseneck hammer along the track to achieve the "gooseneck" function that the hammer body rests on the hard bottom without tilting and the top can swing freely.

[0065] In this embodiment, the gooseneck hammer along the track in S2 includes two types of hammer heads: a stone breaking and squeezing type with a pointed cone side extrusion shape at the bottom and a vertical extrusion shape for breaking and cutting, and a compaction and compaction type with a flat bottom, as well as a "pin-type connecting device" that can be quickly disassembled and assembled.

[0066] It is worth further explaining that the gooseneck hammer along the track will produce a certain rebound effect when encountering hard objects during free fall (especially when encountering large rocks), and this rebound effect will cause the top of the hammer to swing violently in an undirected manner, that is, it will cause a violent lateral collision with the upper "along-track device" and cause damage. After many discussions and tests, it was found that the top of the hammer and the pile driver track are flexibly connected, and at the same time, a release method for this "lateral swing law" and "swing force" is provided (that is, through the "universal joint"); at the same time, this "lateral swing law" is reasonably utilized (the pile hole is slightly expanded with a larger top and a smaller bottom, so that it forms a wedge-shaped pile hole outer mold that gradually expands from bottom to top; at the same time, the hole wall is again slapped and squeezed by the top of the hammer horizontally to form a more compact and stable pile hole protective wall), so as to achieve a complete wedge-shaped pile body effect.

[0067] It is worth further explaining that when the hammer body impacts downward and encounters a backfilled rock layer or a large-diameter, high-strength rock or an underground isolated rock, it is necessary to equip the hammer head with different functions, specifically:

[0068] ① Such as Figure 8 As shown in the figure: When encountering a large amount of riprap filling or blasting and quarrying with stones and filling the gully with some soil particles, the "high-energy impact side squeeze" target should be the main goal, that is, the "single-pointed cone side squeeze" hammer head is used to break the large amount of lumps of stone at the pile hole position under the cone push action, and rammed into the hole wall position outside the pile hole or the soil between the piles outside the hole wall, so as to achieve the effect of breaking the lumps of stone and lateral squeeze to form the pile hole wall protection;

[0069] ② If Fig. 9 As shown in the figure: When encountering clusters or individual large-diameter boulders or isolated boulders buried deep in the soil, because the boulders are too large or the inclined surface is facing upward, the "single-cone side extrusion" hammer head is easy to tilt and cause the entire hammer body to tilt, making it difficult to crush the boulders. In this case, it is necessary to change to a "multi-cone breaking and cutting" hammer head to impact and crush the large-diameter boulders (isolated boulders) at the pile hole position in situ, so as to achieve the effect of crushing in situ and then compacting by tamping or squeezing them into the pile hole laterally;

[0070] ③ The characteristics of the multi-cone cutting hammer head are: at the lower end of the seemingly flat-bottomed hammer head, several pointed cone heads are added to form a "multi-cone cutting" cone head (parallel to the lower end of the cone bottom plane). The specific function is: under the action of the down-track device, the direction of the downward high-energy impact of the hammer body is always vertical and directional, and most of the large rocks buried in the soil have inclined surfaces facing upward (it is difficult to achieve a flat surface facing upward). At this time, any pointed cone on the hammer head will form a huge impact crushing force after touching the large rock, achieving the impact crushing effect.

[0071] ④ Such as Fig.10 As shown: when the stone breaking and squeezing are completed and the pile hole meets the design requirements, the hammer head is quickly disassembled to form a "flat-headed" tamping hammer head (hammer body): In order to achieve the purpose of rapid disassembly, the connection method of the hammer head and the hammer body adopts a "pin-type connection device" to improve the construction efficiency.

[0072] It is worth further explaining that the micro-expansion of the pile formed by S2-S8 can improve the bearing capacity of the pile through the difference in cross-sectional area. The cross-sectional area at the top of the pile is larger than that at the bottom, which makes the pile more firmly embedded in the soil like a nail, and its stability is maximized.

[0073] It is worth further explaining that the rock-breaking and rock-extruding type gooseneck hammer with a tapered bottom is mainly used for impact crushing rocks in the soil. During the impact process, the broken rocks are squeezed around under the action of the impact force and gradually mixed with the soil during the extrusion process. During each impact of the rock-breaking and rock-extruding type gooseneck hammer, the rocks and soil around the pile hole are squeezed, and then squeezed tighter and tighter, forming a natural, complete and solid earth and stone protective wall for the pile hole.

[0074] Among them, the tamping and compacting type along-track gooseneck hammer with a flat bottom is mainly used for compaction operations after filling replacement materials in the pile hole opened up by the tamping and compacting type along-track gooseneck hammer with a conical bottom.

[0075] It is worth further explaining that there is another drilling method in S2: normal drilling: using a gooseneck hammer along the track to impact the soil frequently from top to bottom to form a pile hole at the pile site; the downward impact of the gooseneck hammer along the track breaks the stones, and the broken stones squeeze the soil laterally. The lateral soil and gravel are mixed more and more densely due to the squeezing, thereby forming a pile hole and a complete and solid protective wall of the pile hole.

[0076] It is worth further explaining that the step in S3 is to repeatedly and multiple times perform multi-segment shaping of the lower pile body.

[0077] It is worth further explaining that the length of the along-track gooseneck hammer, flat-cone long-necked middle hammer and flat-cone flat hammer in S2-S7 needs to be slightly longer than the thickness of the soft soil layer or the burial depth, so that the hammer handles on the top of the along-track gooseneck hammer, flat-cone long-necked middle hammer and flat-cone flat hammer can always be exposed from the floor surface, which is beneficial to the connection between the hanging ear and the hammer body and improves construction efficiency.

[0078] It is worth further explaining that the wedge-shaped composite bulk material pile is constructed through the above steps to form a wedge-shaped bulk material pile body with multiple sections of pile bodies with different diameters and shapes stacked on the same vertical line and with the diameter gradually increasing from bottom to top.

[0079] Among them, the top of the wedge-shaped composite bulk material pile is wedge-shaped, and the pile body is also a wedge-shaped that is larger at the top and smaller at the bottom. By applying and transmitting compressive stress from top to bottom, the density, strength and stability of the entire pile body are improved. At the same time, in terms of construction, because different hammers are replaced layer by layer and step by step for tamping construction, a certain interval or rest period is obtained in the construction process. At the same time, through this process, the bulk material pile and the retaining wall outside the pile body and the soil outside the retaining wall form a horizontal composite whole, which greatly improves the strength and stability of the entire foundation.

[0080] It is worth further explaining that the wedge-shaped composite bulk material pile includes a lower pile body, a middle pile body, an upper wedge-shaped pile body, and a top pile body from bottom to top, and the interface diameter gradually increases from bottom to top.

[0081] The cross-sectional diameter of the lower pile body is smaller than that of the middle pile body, and the cross-sectional diameter of the upper wedge-shaped pile body is 20-40 cm larger than that of the middle pile body.

[0082] It is worth further explaining that under the action of the hammer and the tamping, a wedge-shaped pile body with a larger top and a smaller bottom is formed to adapt to the transmission characteristics of the upper load compressive stress, that is, to achieve:

[0083] ① Under the action of vertical compressive stress, the more the bulk material pile is compressed, the denser it becomes and the higher the compressive strength;

[0084] ② Under the compressive stress of the wedge-shaped pile, the soil between the piles becomes denser and denser. On the contrary, the restraining effect on the pile becomes stronger;

[0085] ③Triple effect: The pile body is further compacted, and the close combination between the pile body and the retaining wall promotes the increase of the density of the soil between the piles and the lateral restraint force on the pile body, which is further improved synchronously.

[0086] It is worth further explaining that the value advantage of this wedge-shaped composite bulk material pile is based on the total price of a single pile and its bearing capacity, that is, the total price of a single pile ÷ the bearing capacity of a single pile = unit value, so the size of the single pile price and the bearing capacity of a single pile can directly reflect its value advantage. That is, the smaller the volume of the pile, the lower the total price, and the greater the bearing capacity of a single pile, the more obvious its price advantage, and the bulk materials are generally local cheap materials produced locally, which forms the high cost-effectiveness of this type of pile.

[0087] Experimental example

[0088] like Fig.13 As shown, under the same construction conditions and environment:

[0089] After the construction of the wedge-shaped composite pile with a pile diameter (upper / lower end) of 1500 / 850mm was completed, the estimated characteristic value of the bearing capacity could reach 1504kPa at a testing depth of 5m. After testing, its maximum bearing capacity could reach 2136kN.

[0090] After the construction of the wedge-shaped composite pile with a pile diameter (upper / lower end) of 1500 / 850mm was completed, the estimated characteristic value of the bearing capacity could reach 1504kPa at a testing depth of 10m. After testing, its maximum bearing capacity could reach 2136kN.

[0091] After the construction of the wedge-shaped composite pile with a pile diameter (upper / lower end) of 1500 / 850mm was completed, the estimated characteristic value of the bearing capacity could reach 1504kPa at a testing depth of 15m. After testing, its maximum bearing capacity could reach 2136kN.

[0092] After the construction of the wedge-shaped composite pile with a pile diameter (upper / lower end) of 1500 / 850mm is completed, the estimated characteristic value of the bearing capacity can reach 1504kPa when the detection depth is 20m. After testing, its maximum bearing capacity can reach 2136kN.

[0093] The pile body formed by the combination hammer construction with a pile body diameter (upper end / lower end) of 1700 / 1250mm has an estimated characteristic bearing capacity value of 950kPa at a testing depth of 5m. After testing, its maximum bearing capacity can reach 810kN.

[0094] The pile body formed by the combination hammer construction with a pile body diameter (upper end / lower end) of 1700 / 1250mm has an estimated characteristic bearing capacity value of 950kPa at a testing depth of 5m. After testing, its maximum bearing capacity can reach 810kN.

[0095] The pile body formed by the combination hammer construction with a pile body diameter (upper end / lower end) of 1700 / 1250mm has an estimated characteristic bearing capacity value of 950kPa at a testing depth of 10m. After testing, its maximum bearing capacity can reach 810kN.

[0096] The pile body formed by the combination hammer construction with a pile body diameter (upper end / lower end) of 1700 / 1250mm has an estimated characteristic bearing capacity value of 950kPa at a testing depth of 15m. After testing, its maximum bearing capacity can reach 810kN.

[0097] For the pile body formed by the combination hammer construction with a pile diameter (upper / lower end) of 1700 / 1250mm, when the testing depth is 20m, the estimated characteristic value of the bearing capacity can reach 950kPa. After testing, its maximum bearing capacity can reach 810kN.

[0098] By comparison, it can be seen that under the same detection depth, the maximum load capacity detected by the wedge-shaped composite pile with a relatively small pile diameter is actually greater than the pile with a larger diameter formed after the original combination hammer construction.

[0099] It is worth further explaining that the conclusion drawn from this test is that the reason why the bearing capacity of this type of pile is greatly increased is mainly due to the construction method of the present invention and the wedge shape of the pile body. This experiment was conducted by Jiangxi Provincial Architectural Design and Research Institute Group Co., Ltd.

[0100] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the protection scope of the present invention.

Claims

1. A construction method for a wedge-shaped composite bulk material pile, Features: The following steps are involved: S1. Stop the construction equipment at the construction area, align the gooseneck hammer of the pile driver with the pile position to prepare for the piling operation; S2. Micro-hole expansion: The gooseneck hammer along the track tamps the soil from top to bottom. The downward impact of the gooseneck hammer along the track crushes the stones. The crushed stones squeeze the soil laterally. The soil and crushed stones on the side are mixed more and more densely due to the squeezing, thereby forming a complete and solid protective wall of the pile hole. At the same time, due to the lateral connection between the top of the gooseneck hammer along the track and the pile driver track, a flexible connection is achieved through the "universal joint", forming a "gooseneck" function; during the injection process, especially when the bottom of the hammer touches a large-diameter stone or hard object, the upper end of the gooseneck hammer along the track will naturally produce a certain degree of micro-swing (front and back or left and right), and the "universal joint" can leave a certain amount of activity space for this swing, forming a flexible connection effect, so that it can not only eliminate the adverse factors caused by the rigid connection between the original pile driver track and the gooseneck hammer along the track (causing hard collision with the pile driver track and corresponding distortion and damage), but also achieve a certain degree of micro-hole expansion effect from bottom to top on the pile hole, forming a complete and continuous wedge-shaped pile hole; S3, lower pile formation: after the pile hole and stable retaining wall are formed, the replacement material is filled in sections from bottom to top, and the hammer head is replaced for section-by-section tamping to ensure that each section of the lower pile body reaches the vertical compaction of the pile body and the lateral extrusion of the hole wall, so that the pile body and the retaining wall form a tightly combined vertical bearing body; at the same time, a wedge-shaped replacement material lower pile body with a diameter gradually increasing from bottom to top is formed; S4, middle pile formation: fill the pile hole with replacement material in sections from bottom to top, and tamp it in sections at the same time, to ensure that each section of the middle pile body reaches the vertical compaction of the pile body and the lateral extrusion of the hole wall, so that the pile body and the retaining wall form a tightly combined vertical bearing body; at the same time, a wedge-shaped replacement material middle pile body with a diameter gradually increasing from bottom to top is formed; S5, upper pile body mold: after the lower and middle pile bodies are formed, the replacement material is continued to be backfilled in the pile hole, and then the flat cone long neck middle hammer is replaced for continuous tamping, and the middle and lower wedge-shaped pile bodies are further tamped, compacted and expanded by the tamping force transmission, and at the same time, the upper wedge-shaped pile body mold with a larger upper part and a smaller lower part is formed; S6, forming the upper pile body: the inner cavity of the outer mold of the wedge-shaped pile body formed by the operation in S5 is filled with replacement material; the outer mold of the wedge-shaped pile body backfilled with replacement material in S5 and the replacement material in the mold are continuously rammed with a flat cone flat hammer, and the ramming is stopped after the hammer withdrawal standard is reached, forming a wedge-shaped pile body of the upper part of the replacement material that gradually expands from bottom to top, and at the same time forming an expanded outer mold (ramming pit) at the top of the pile body; S7, forming the pile top: filling the outer mold at the top of the pile body with replacement material, and continuing to compact it with a flat cone hammer to form a wedge-shaped expanded diameter pile body at the top; S8. The wedge-shaped composite bulk material pile is constructed through the above steps to form a complete and continuous wedge-shaped composite bulk material pile body, which is composed of multiple sections of pile bodies with different diameters and shapes stacked on the same vertical line, and the pile body with a diameter gradually increasing from bottom to top is tightly integrated with the retaining wall.

2. The construction method of the wedge-shaped composite granular material pile according to claim 1, Features: The diameter, mass and height of the gooseneck hammer along the track in S2 are configured accordingly according to different design requirements, thickness of soft soil layer or burial depth to meet the hole depth and pile specifications required by the design; at the same time, through a simple connection method, the length, weight or diameter of the hammer body can be increased or decreased (increased or decreased) as needed according to different stratum conditions, so as to achieve a one-hammer-multiple-purpose effect to adapt to various geological conditions and design requirements.

3. The construction method of the wedge-shaped composite granular material pile according to claim 1, Features: The length of the gooseneck hammer, flat cone long neck middle hammer and flat cone flat hammer in S2 needs to be slightly longer than the thickness of the soft soil layer or the burial depth, so that the hammer handles on the top of the gooseneck hammer, flat cone long neck middle hammer and flat cone flat hammer can always be exposed from the floor surface, which is conducive to the automatic connection between the hanging ear and the hammer body and improves the construction efficiency; at the same time, the burial depth of each hammer body can be intuitively understood, which is convenient for construction records and improving the quality control effect and efficiency.

4. The construction method of the wedge-shaped composite granular material pile according to claim 1, Features: The replacement material in S3 is a bulk material such as crushed stone soil, sandy soil, construction waste aggregate, industrial waste aggregate, etc., the particle size of which should not be too large. Cementitious materials can be added when there are special design requirements.

5. The construction method of the wedge-shaped composite granular material pile according to claim 1, Features: The solid protective wall formed by the mixture of soil and gravel in S2 provides peripheral support and restraint for the replacement material during the compaction process, limits the displacement material from being squeezed and expanded around due to the impact of high-energy tamping, improves the efficiency and effect of pile formation and the density of the pile body, and at the same time, after completing the restraint effect, forms a tight fit with the replacement material pile body, and finally forms a load-bearing pile body with an enlarged diameter and a superimposed cross-sectional area, so as to improve the bearing capacity of a single pile.

6. The construction method of the wedge-shaped composite granular material pile according to claim 1, Features: The gooseneck type hammer with flexible connection at the top of the pile driver in S2 is mainly to set one or more universal joints at the top of the gooseneck type hammer to achieve the "gooseneck" function that the hammer body rests on the hard bottom without tilting and the top can swing freely.

7. The construction method of the wedge-shaped composite granular material pile according to claim 1, Features: The track-following gooseneck hammer in S2 includes two types of hammer heads: a stone-breaking and stone-extruding type with a pointed cone side extrusion shape at the bottom and a stone-breaking and stone-extruding type with a flat bottom, and a "pin-type connection device" that can be quickly disassembled and assembled.

Images