Steel sheet pile with negative Poisson's ratio and construction method thereof

Abstract

The invention discloses a negative Poisson's ratio steel sheet pile and a construction method thereof. The steel sheet pile comprises a pile cap, at least one pile body section and a pile tip section. The pile body section and the pile tip section are both of a shell structure, and the horizontal section of the pile body section is consistent with the horizontal section of the upper portion of the pile tip section. Wherein the two longitudinal ends of the pile body section are arranged in parallel at intervals, and the middles of the two transverse ends of the pile body section are bent towards the center of the pile body section, so that the pile body section forms an hourglass-shaped structure on the horizontal section; the wall thickness of the pile body section and the wall thickness of the pile tip section are filled with negative poisson ratio materials. The lower portion of the pile tip section extends downwards along the transverse end of the upper portion to form a lower end sharp corner structure. On the premise that pile side resistance is not lost, the bending resistance of the steel sheet pile can be enhanced, the inertia moment of the section is increased, remarkable anti-seismic and energy-absorbing characteristics can be achieved, the bearing capacity under the vibration impact load and the buffering effect on a supporting structure are improved, and the service life of the steel sheet pile is prolonged. The device is suitable for areas frequently bearing vibration and explosion impact loads.

Description

Technical Field

[0001] The invention relates to a steel sheet pile technology, belongs to the field of infrastructure construction, and specifically relates to a steel sheet pile with a negative Poisson's ratio and a construction method thereof. Background Art

[0002] Special-shaped steel sheet piles are specially designed steel sheet piles. Their cross-sectional shape, locking structure or overall structure are different from those of traditional steel sheet piles. They have been widely used in high-rise building deviation correction and foundation settlement control.

[0003] Although special-shaped steel sheet piles have the characteristics of strong adaptability, special-shaped steel sheet piles still have the following defects: 1. Due to their unique structure, special-shaped steel sheet piles have small moment of inertia and weak bending resistance, and the use of high-strength steel or adding corrosion-resistant coatings on the surface will increase the overall cost; 2. The pile body mainly adopts steel structure, which has poor seismic energy absorption characteristics and cannot be used on a large scale under conditions of frequent vibration and explosive impact loads (such as coastal retaining pipe pile walls in high-frequency earthquake zones and foundation treatments such as mines and tunnels that require frequent blasting); Specifically, traditional steel sheet piles have a positive Poisson's ratio effect, that is, when the material is stretched or compressed in one direction, it will shrink or expand accordingly in the lateral direction (perpendicular to the force direction). When facing high-intensity seismic waves, blasting shocks or other complex stress conditions, positive Poisson's ratio materials may not provide sufficient protection. At this time, steel sheet piles need to exhibit a negative Poisson's ratio effect, that is, the unique lateral compression characteristics of negative Poisson's ratio materials and negative Poisson's ratio structures when subjected to force, which makes it have great potential in absorbing and dissipating vibration energy, buffering vibration isolation and reducing structural deformation.

[0004] Therefore, there is an urgent need for a special steel sheet pile with negative Poisson's ratio and large moment of inertia to meet the needs of foundation treatment in areas that are frequently subjected to vibration and impact loads. Summary of the invention

[0005] The purpose of the present invention is to provide a steel sheet pile with a negative Poisson's ratio, which can not only enhance the bending resistance of the steel sheet pile and increase the moment of inertia of the cross section without losing the pile side resistance, but also has significant seismic energy absorption characteristics, improves the bearing capacity under vibration impact loads and the buffering effect on the supporting structure.

[0006] To achieve the above object, a steel sheet pile with a negative Poisson's ratio includes a pile cap, at least one pile body section, and a pile tip section connected in sequence from top to bottom;

[0007] It is characterized in that

[0008] The two longitudinal ends of the pile body are arranged in parallel and spaced apart, and the middle parts of the two transverse ends are bent toward the center of the pile body, so that the pile body forms an hourglass-shaped structure on the horizontal cross section;

[0009] The wall thickness of the pile body section and the pile tip section are filled with negative Poisson's ratio materials;

[0010] The lower part of the pile tip section extends downward along the transverse end of the upper part to form a lower end pointed angle structure.

[0011] In some embodiments, the pile body section and the pile tip section are respectively provided with a first slot hole and a second slot hole along a circumferential closed loop;

[0012] The centers of the first slot hole and the second slot hole are consistent with the center of the wall thickness, and the upper ends are open and the lower ends are closed;

[0013] The negative Poisson's ratio material is filled in the first slot and the second slot.

[0014] In some embodiments, the length of each longitudinal end of the pile body segment is equal to the distance between a pair of longitudinal ends;

[0015] The included angle β between the transverse end and the longitudinal end of the pile section is 65°-75°.

[0016] In some embodiments, the relationship between the distance h1 from the first slot to the bottom end of the pile body segment and the overall height h of the pile body segment is:

[0017] h1=(0.1~0.15)h

[0018] The relationship between the distance h2 from the second slot to the bottom end of the pile tip section and the outer length a of the longitudinal end of the pile tip section is:

[0019]

[0020] Among them, α is the angle between the tip of the pile and the horizontal plane, and the value is 45°-50°;

[0021] The relationship between the width t1 of the first slot and the second slot and the outer length a of the longitudinal end of the pile body section is:

[0022] t1=(0.04~0.1)a.

[0023] In some embodiments, the transverse ends between adjacent pile shaft segments and the longitudinal ends of the pile shaft segments adjacent to the pile tip segment are both provided with edge chamfers.

[0024] In some embodiments, the radius of the outer fillet R1 where the lateral end and the longitudinal end of the pile segment are connected is the same as the radius of the outer fillet R2 where the middle part of the lateral end of the pile segment is bent, and

[0025] R1=R2=0.05a

[0026] Where a is the outer length of the longitudinal end of the pile section;

[0027] The radius of the fillet R3 on the inner side where the lateral end of the pile section is connected to the longitudinal end and close to the first slot hole is the same as the radius of the fillet R4 on the inner side where the middle part of the lateral end of the first slot hole is bent and close to the first slot hole, and

[0028] R3=R4=0.05c

[0029] Wherein, c is the inner length of the longitudinal end of the pile section.

[0030] In some embodiments, the pile cap has a pile eaves, and a positioning assembly located below the pile eaves;

[0031] When driving, the positioning assembly is used to limit the upper end of the pile body section or the pile tip section.

[0032] In some embodiments, the positioning assembly is an arc-shaped structure and is located at the connection between the transverse end and the longitudinal end of the pile body segment. The positioning assembly includes a first positioning plate and a second positioning plate of an arc-shaped structure;

[0033] The first positioning plate can contact the inner side of the pile body segment, and the second positioning plate can contact the outer side of the pile body segment.

[0034] In some embodiments, the inner edge of the pile eaves extends inwardly at equal intervals relative to the inner contour of the pile body section, and the outer edge extends outwardly at equal intervals relative to the outer contour of the pile body section;

[0035] The relationship between the upper and lower thickness h3 of the pile cap and the thickness h1 from the first slot to the bottom of the pile body section is:

[0036] h3 = (1 ~ 1.2) h1.

[0037] The present invention also aims to provide a construction method for steel sheet piles with a negative Poisson's ratio, which can install the pile tip section and the pile body section in sections, which not only reduces the adverse stress of the pile section during transportation and lifting, but also ensures uniform impact on the pile section below, avoids local deformation and affects the subsequent connection effect, and is suitable for areas that are frequently subjected to vibration and explosion impact loads.

[0038] A construction method for a steel sheet pile with a negative Poisson's ratio comprises the following steps:

[0039] Step 1, clean up the pile sinking point;

[0040] Step 2, transporting the steel sheet pile with negative Poisson's ratio as claimed in claim 2 to the vicinity of the pile sinking point and performing pile sinking operation;

[0041] Step 2-1, first arrange the pile tip section vertically and align it with the pile sinking point, and then install a pile cap on the top of the pile tip section to ensure that the pile body is evenly compressed. Drive the pile until the top of the pile tip section is at least 0.5m above the soil surface, and then remove the pile cap;

[0042] Step 2-2, placing the pile body section above the pile tip section so that the lower end of the pile body section and the upper end of the pile tip section are closely connected and calibrated;

[0043] Welding the longitudinal ends of the pile body section and the pile tip section;

[0044] Step 2-3, after the welding is naturally cooled, a pile cap is placed on the upper end of the pile body and driven until the upper end of the pile body is at least 0.5m above the soil surface, and then the pile cap is removed;

[0045] The upper pile section and the lower pile section are welded at the butt joint at the longitudinal ends;

[0046] Step 2-4, connect other pile sections to the pile section below in sequence, repeat steps 2-3, until all pile sections are driven into the soil, and the negative Poisson's ratio steel sheet pile is driven;

[0047] When the uppermost pile section is driven into the soil, the pile cap is welded to the uppermost pile section to ensure integrity;

[0048] When driving stops, the brim of the pile cap contacts and compacts the soil surface below to ensure that the pile cap protects the internal structure of the pile body.

[0049] Compared with the prior art, the present invention has a negative Poisson's ratio steel sheet pile. On the one hand, the pile tip section and the pile body section both adopt a closed hourglass-shaped hollow section. When the surface of the steel sheet pile can still maintain a large-area extrusion contact with the soil, the inertia moment of the section can be increased. Therefore, the bending resistance of the steel sheet pile is enhanced under the premise of ensuring that the pile side resistance is not lost. On the other hand, the hourglass-shaped section of the pile body has a negative Poisson's ratio effect along the longitudinal direction of the section, and negative Poisson's ratio materials are arranged in the pile body section and the pile tip section. The negative Poisson's ratio material can bear the vertical load together with the surrounding steel plates and has significant anti-seismic energy absorption characteristics. The two work together to increase the bidirectional vibration isolation energy absorption effect when the pile body is subjected to horizontal and vertical vibration impact loads, and improve the bearing capacity of the steel sheet pile under vibration impact loads and the buffering effect on the supporting structure; it is suitable for areas that are frequently subjected to vibration and explosion impact loads;

[0050] The volume of the polyurethane elastomer is determined after determining the overall height h of the pile body, the outer length a of the longitudinal end, and the angle α between the sharp corner of the lower end of the pile tip section and the horizontal plane, so as to avoid the problem of mismatch of the volume of the polyurethane elastomer due to the different structural dimensions of the pile body section and the pile tip section, so that the pile body section and the pile tip section can have a better negative Poisson's ratio effect when they can withstand impact loads; in addition, the connection between the transverse end and the longitudinal end of the pile body section adopts a rounded corner transition, and the inward bend of the middle part of the transverse end also adopts a rounded corner transition, which can avoid the problem of stress concentration caused by the sharp transition of the cross section, so as to improve the bending resistance and other capabilities of the steel sheet pile;

[0051] Since the inner and outer edges of the pile cap extend inward and outward at equal intervals relative to the fixed plate, and a first positioning plate and a second positioning plate are provided, when the pile cap is driven, a positioning connection between the pile cap and the pile body section / pile tip section can be achieved, thereby ensuring uniform impact on the pile section below and avoiding local deformation that affects the subsequent connection effect. When the steel sheet pile is driven, the pile cap on the top of the uppermost pile body section can increase the contact area between the whole and the foundation soil, thereby increasing the bearing capacity of the steel sheet pile, reducing the horizontal and vertical displacements of the pile section, and can play a certain protective role on the pile body section and pile tip section below. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is an overall schematic diagram of the present invention;

[0053] Figure 2 It is a schematic diagram of the pile body section in the present invention;

[0054] Figure 3 is a top view of a pile body section in the present invention;

[0055] Figure 4 is a schematic cross-sectional view of a pile body section in the present invention;

[0056] Figure 5 is a schematic diagram of a pile tip section in the present invention;

[0057] Figure 6 is a schematic cross-sectional view of a pile tip section in the present invention;

[0058] Figure 7 It is a left side view of the pile tip section in the present invention;

[0059] Figure 8 is a schematic diagram of a pile cap in the present invention;

[0060] Fig. 9 is a bottom view of the pile cap in the present invention (projection of the pile body section on the pile cap);

[0061] Fig.10 is a schematic diagram of the connection of adjacent pile body sections in the present invention;

[0062] In the figure: 10, pile body section, 11, first slot hole;

[0063] 20. pile tip section, 21. second slot hole, 22. sharp corner;

[0064] 30. pile cap, 31. pile eaves, 32. first positioning plate, 33. second positioning plate;

[0065] 40. Negative Poisson's ratio materials;

[0066] 50. Chamfer the edges. DETAILED DESCRIPTION

[0067] In order to make the purpose, technical solution and advantages of the technical solution of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described in conjunction with the drawings of specific embodiments of the present invention. The same figure marks in the drawings represent the same parts. It should be noted that the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described 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.

[0068] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not necessarily indicate a quantity limitation. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0069] The description is made by taking the vertical center of the steel sheet pile close to the negative Poisson's ratio as the inside and the vertical center of the steel sheet pile far from the negative Poisson's ratio as the outside;

[0070] like Figure 1 , Figure 2 , Figure 3 , Figure 5 As shown, the present steel sheet pile with negative Poisson's ratio comprises a pile cap 30, at least one pile body section 10, and a pile tip section 20 which are sequentially connected from top to bottom;

[0071] The pile body section 10 and the pile tip section 20 are both shell structures, and the horizontal cross section of the pile body section 10 is consistent with the horizontal cross section of the upper part of the pile tip section 20;

[0072] The two longitudinal ends of the pile body section 10 are arranged in parallel and spaced apart, and the middle parts of the two transverse ends are bent toward the center of the pile body section 10, so that the pile body section 10 forms an hourglass-shaped structure in the horizontal cross section;

[0073] The wall thickness of the pile body section 10 and the pile tip section 20 are filled with negative Poisson's ratio material 40;

[0074] The lower portion of the pile tip section 20 extends downward along the lateral end of the upper portion to form a lower end sharp corner 22 structure.

[0075] Specifically, the pile cap 30 is mounted above the uppermost pile body section 10; it can be understood that since the profile of the pile body section 10 is consistent with the profile of the pile tip section 20, the pile cap 30 can be mounted on the upper end of the pile tip section 20 and the upper end of each pile body section 10 to facilitate the driving of the steel sheet pile;

[0076] The pile body section 10 and the pile tip section 20 can both adopt an integrally formed symmetrical shell structure, which can eliminate stress concentration and potential cracks at the welded joints and improve the overall tensile, bending and fatigue resistance. The number of pile body sections 10 can be flexibly determined according to engineering requirements, such as Figure 1 As shown, the number of the pile body segments 10 is 2; the horizontal cross section of the pile body segment 10 is consistent with the horizontal cross section of the upper portion of the pile tip segment 20. It can be understood that the inner and outer contours of the pile body segment 10 are consistent with the inner and outer contours of the pile tip segment 20;

[0077] The length of each longitudinal end of the pile body segment 10 can be equal to the distance between the two longitudinal ends, that is, the line connecting the four corners of the pile body segment 10 is a square structure; the middle part of the transverse section of the pile body segment 10 is bent inward so that the angle β between it and the longitudinal end is 65°-75°. From the top view of the pile body segment 10, the pile body segment 10 presents a better hourglass structure to enhance the bending resistance of the steel sheet pile;

[0078] The negative Poisson's ratio material 40 can be foamed metal such as foamed aluminum, foamed copper, or honeycomb metal; preferably, the negative Poisson's ratio material 40 is a polyurethane elastomer; the negative Poisson's ratio polyurethane elastomer is filled in the wall thickness of the pile body section 10 and the pile tip section 20, and can bear the vertical load together with the surrounding steel plates (pile body section 10, pile tip section 20) and has significant seismic energy absorption characteristics;

[0079] The lower part of the pile tip section 20 is a sharp corner 22 structure and the outer surface is smooth, which can increase the driving speed without affecting the friction resistance of the pile side;

[0080] Compared with the special-shaped steel sheet piles with solid cross-section, the closed hourglass-shaped hollow cross-section of the steel sheet pile can increase the moment of inertia of the cross-section, and the surface of the pile section can still maintain a large area of ​​compression contact with the soil, thereby enhancing the bending resistance of the steel sheet pile without losing the side resistance of the pile. On the other hand, a polyurethane elastomer with a negative Poisson's ratio effect is arranged in the pile body section 10 and the pile tip section 20. The negative Poisson's ratio material 40 can share the vertical load with the surrounding steel plate and has significant anti-seismic energy absorption characteristics. Therefore, the steel sheet pile has a negative Poisson's ratio effect while being subjected to lateral dynamic loads through the hourglass-shaped cross-sectional structure, thereby increasing the bidirectional vibration isolation and energy absorption effect of the pile body when it is subjected to horizontal and vertical vibration impact loads, and improving its bearing capacity under vibration impact loads and the buffering effect on the supporting structure; in addition, the pile body sections 10 can be connected to each other in multiples, that is, the construction method of segmented driving can be adopted so that the steel sheet pile can be constructed under low clearance conditions, which is convenient for transportation and reduces the adverse stress generated by the pile body section 10 during transportation.

[0081] In some examples of the present invention, Figure 2 , Figure 4 , Figure 5 , Figure 6 As shown, the pile body section 10 and the pile tip section 20 are provided with a first slot hole 11 and a second slot hole 21 along a circumferential closed loop, respectively;

[0082] The center of the first slot hole 11 and the second slot hole 21 are consistent with the center of the wall thickness, and the upper end is open and the lower end is closed;

[0083] The negative Poisson's ratio material 40 is filled in the first slot 11 and the second slot 21;

[0084] Specifically, the first slot hole 11 and the second slot hole 21 have the same size, and the center is consistent with the center of the wall thickness, that is, the upper part of the pile body section 10 and the upper part of the pile tip section 20 are equivalent to the steel plates arranged with inner and outer spacing, and the thickness of the steel plates is consistent;

[0085] The first slot hole 11 and the second slot hole 21 of the circumferential closed loop are used to fill the negative Poisson's ratio material 40. When the steel sheet pile is sunk and subjected to vertical load, the negative Poisson's ratio material 40 can contact the steel plate of the pile body section 10 / pile tip section 20, thereby absorbing and dissipating vibration energy, buffering and isolating vibration, and reducing structural deformation.

[0086] Further, such as Figure 4 , Figure 7 As shown, the angle β between the transverse end and the longitudinal end of the pile body section 10 is 65°-75°;

[0087] The two longitudinal ends of the pile body section 10 are arranged in parallel and spaced apart, and the length of each longitudinal end is equal to the distance between the two longitudinal ends;

[0088] In some examples of the present invention, the relationship between the distance h1 from the first slot 11 to the bottom end of the pile body section 10 and the overall height h of the pile body section 10 is:

[0089] h1=(0.1~0.15)h

[0090] The distance h2 from the second slot 21 to the bottom end of the pile tip section 20 can be determined according to the angle α between the sharp corner 22 at the lower end of the pile tip section 20 and the horizontal plane, and the angle α can be 45°-50°, that is, the relationship between the distance h2 from the second slot 21 to the bottom end of the pile tip section 20 and the outer length a of the longitudinal end of the pile tip section 20 is:

[0091]

[0092] like Figure 4 , Figure 6 As shown, the relationship between the width t1 of the first slot hole 11 and the second slot hole 21 and the outer length a of the longitudinal end of the pile body section 10 is:

[0093] t1=(0.04~0.1)a

[0094] As explained, the horizontal cross section of the pile shaft section 10 is consistent with the horizontal cross section of the upper portion of the pile tip section 20, so the outer length of the longitudinal end of the pile shaft section 10 and the outer length of the longitudinal end of the pile tip section 20 can both be represented by a.

[0095] The width t1 of the first slot 11 and the second slot 21 determines the volume of the negative Poisson's ratio material 40 that can be accommodated.

[0096] In this embodiment, the volume of the negative Poisson's ratio material 40 is determined by determining the overall height h of the pile body segment 10, the outer length a of the longitudinal end, and the angle α between the sharp corner 22 of the lower end of the pile tip segment 20 and the horizontal plane, thereby avoiding the problem of volume mismatch of the negative Poisson's ratio material 40 due to the different structural dimensions of the pile body segment 10 and the pile tip segment 20, so that the pile body segment 10 and the pile tip segment 20 can have a better negative Poisson's ratio effect when they can withstand impact loads.

[0097] In some examples of the present invention, Figure 2 , Figure 3 , Fig.10 As shown, the transverse ends between adjacent pile segments 10 and the longitudinal ends of the pile segments 10 adjacent to the pile tip segment 20 are both provided with edge chamfers 50;

[0098] Specifically, the edge chamfer 50 is arranged in the center, and the relationship between the length d and the outer length a of the longitudinal end of the pile body section 10 is:

[0099] d=0.9a

[0100] The relationship between the width w of the edge chamfer 50 and the outer length a of the longitudinal end of the pile shaft section 10 is:

[0101] w=0.01a

[0102] In this embodiment, chamfers 50 are provided at the lateral ends of the pile body section 10 and the pile tip section 20 to facilitate welding connection between the pile body sections 10 and the pile tip section 20 after docking, so as to avoid fracture due to insufficient connection force during smooth docking or excessive welding seam affecting the construction and installation of the steel sheet pile.

[0103] In some examples of the present invention, Figure 3 As shown, the radius of the outer fillet R1 where the lateral end and the longitudinal end of the pile body section 10 are connected is the same as the radius of the outer fillet R2 where the middle part of the lateral end of the pile body section 10 is bent, and

[0104] R1=R2=0.05a

[0105] Wherein, a is the outer length of the longitudinal end of the pile section 10;

[0106] The radius of the fillet R3 on the inner side where the lateral end and the longitudinal end of the pile body section 10 are connected and close to the first slot hole 11 is the same as the radius of the fillet R4 on the inner side where the middle part of the lateral end of the first slot hole 11 is bent and close to the first slot hole 11, and

[0107] R3=R4=0.05c

[0108] Wherein, c is the inner length of the longitudinal end of the pile body section 10;

[0109] Specifically, the connection between the transverse end and the longitudinal end of the pile body segment 10 adopts a rounded transition, and the inward bend of the middle part of the transverse end also adopts a rounded transition. Since the pile body segment 10 itself is a shell structure, that is, the pile body segment 10 has a certain thickness, there are naturally internal and external rounded corners at the connection and the bend, especially when the pile body segment 10 is provided with a circumferential closed loop first slot 11, at this time, there are relatively more rounded corners;

[0110] In this example, rounded corners are used at the above-mentioned connections and bends to avoid stress concentration caused by sharp transitions in the cross-section, so as to improve the bending resistance of the steel sheet pile. In addition, it can be understood that the horizontal cross-section of the pile body section 10 is consistent with the horizontal cross-section of the upper part of the pile tip section 20, and accordingly, the pile tip section 20 is also provided with the above-mentioned rounded corners.

[0111] In some examples of the present invention, Figure 8 , Fig. 9 As shown, the pile cap 30 has a pile eave 31 and a positioning assembly located below the pile eave 31;

[0112] When driving, the positioning assembly is used to limit the upper end of the pile body section 10 or the pile tip section 20;

[0113] Specifically, the positioning component can be a third slot hole that is consistent with the contour of the pile body segment 10, that is, the inner and outer sides of the pile body segment 10 shell can be inserted into the third slot hole; the positioning component can also be an inner and outer plate, that is, the inner plate contacts the inner side of the pile body segment 10 shell, and the outer plate contacts the outer side of the pile body segment 10 shell. When the pile cap 30 is matched above the pile body segment 10, the positioning connection of the pile body segment 10 is achieved through the positioning component; it is explained that because the contour of the pile body segment 10 is consistent with the contour of the pile tip segment 20, the positioning component in the pile cap 30 can position the pile body segment 10 and the pile tip segment 20 accordingly;

[0114] After the steel sheet pile is driven, the pile cap 30 on the top of the uppermost pile body section 10 can increase the contact area between the whole and the foundation soil, thereby increasing the bearing capacity of the steel sheet pile and reducing the horizontal and vertical displacements of the pile section; at the same time, the pile cap 30 can play a certain protective role on the pile body section 10 and the pile tip section 20 below, preventing surface water from invading the first slot hole 11 and the second slot hole 21 and corroding the negative Poisson's ratio material 40, as well as the pile body section 10 and the pile tip section 20 themselves.

[0115] In some examples of the present invention, Figure 8 , Fig. 9 As shown, the positioning assembly is an arc-shaped structure and is located at the connection between the transverse end and the longitudinal end of the pile body section 10. The positioning assembly includes a first positioning plate 32 and a second positioning plate 33 of an arc-shaped structure;

[0116] The first positioning plate 32 can contact the inner side of the pile body section 10, and the second positioning plate 33 can contact the outer side of the pile body section 10;

[0117] Specifically, there are four first positioning plates 32 and four second positioning plates 33, which are located at the four corners where the transverse end and the longitudinal end of the pile body section 10 are connected, and are all arc-shaped structures to ensure a straight and smooth insertion connection;

[0118] In this example, the first positioning plates 32 and the second positioning plates 33 at the four corners can realize the positioning between the pile cap 30 and the pile body section 10, thereby avoiding the situation of unstable connection when the steel sheet pile is driven;

[0119] In some examples of the present invention, Figure 8 , Fig. 9 As shown, the inner edge of the pile eaves 31 extends inwardly at equal intervals relative to the inner contour of the pile body section 10, and the outer edge extends outwardly at equal intervals relative to the outer contour of the pile body section 10;

[0120] The relationship between the upper and lower thickness h3 of the pile cap 30 and the thickness h1 from the first slot 11 to the bottom end of the pile body section 10 is:

[0121] h3=(1~1.2)h1

[0122] Specifically, the pile flange 31 is a steel plate that is consistent with the pile body section 10 in profile and widens relatively inwardly and outwardly, and the upper end surface is a friction surface;

[0123] Preferably, Fig. 9 As shown, the relationship between the outer length e of the longitudinal end of the pile flange 31 and the outer length a of the longitudinal end of the pile body section 10 is:

[0124] e=(1.2~1.5)a

[0125] In this example, the pile flange 31 has an inward and outward extending structure, and the thickness of the pile cap 30 is set, so that when the steel sheet pile is driven, the impact on the pile body section 10 below can be uniform, avoiding local deformation that affects the subsequent welding effect.

[0126] The present invention provides a method for processing a steel sheet pile with a negative Poisson's ratio, which specifically comprises the following steps:

[0127] S1, the pile body section 10 and the pile tip section 20 are an integrally formed centrally symmetrical shell structure, on which a first slot 11 and a second slot 21 are correspondingly arranged, and during processing, they can be processed by template casting or cutting and stamping;

[0128] The pile cap 30 is formed by using a method such as template casting or drilling;

[0129] S2, grinding the inside and outside of the pile body section 10 and the pile tip section 20, as well as the first slot hole 11 and the second slot hole 21, for example, by sandblasting with a sandblasting machine, and controlling the roughness of the grinding surface to be 39um-75um;

[0130] The upper surface of the pile cap 30 is polished by a sandblaster or a steel brush to obtain a rough surface;

[0131] S3, grinding the longitudinal ends of the pile body section 10 and the pile tip section 20 with an angle grinder to obtain corresponding chamfers 50, so that the relationship between the length d of the chamfer 50 and the outer length a of the longitudinal end of the pile body section 10 is: d=0.9a, and the relationship between the width w of the chamfer 50 and the outer length a of the longitudinal end of the pile body section 10 is: w=0.01a;

[0132] S4, pouring hot negative Poisson's ratio material 40 into the first slot hole 11 and the second slot hole 21 for filling, keeping the pile body section 10 and the pile tip section 20 in a vertical state as a whole during pouring, that is, keeping the upper surface of the corresponding pile section horizontal and stable, and then leaving it to stand for at least 1 hour, so that the negative Poisson's ratio material 40 forms a certain stable strength and has a certain bonding strength with the corresponding slot wall.

[0133] The present invention provides a construction method for a steel sheet pile with a negative Poisson's ratio, which specifically comprises the following steps:

[0134] Step 1, clean the pile sinking point; before sinking the pile, drill a small hole in the axial direction of the pile sinking point to determine whether there are pipelines and obstacles buried underground, and carry out timely treatment after drilling to ensure the quality of pile sinking and avoid losses;

[0135] Step 2, transporting the steel sheet pile with negative Poisson's ratio to the vicinity of the pile sinking point and performing pile sinking operation;

[0136] Step 2-1, first align the pile tip section 20 with the pile sinking point and arrange it vertically, cover the pile tip section 20 with a pile cap 30 to ensure that the pile body is evenly compressed, and drive until the upper end of the pile tip section 20 is at least 0.5m above the soil surface, and then remove the pile cap 30;

[0137] Specifically, due to the large size and weight of the steel sheet pile, it can be hoisted by a crane to facilitate installation, and the pile tip section 20 is driven into the soil by hammering. When driving, a pile cap 30 is placed on the upper part of the pile tip section 20 to ensure that the pile body is evenly compressed. Finally, the upper end of the pile tip section 20 is at least 0.5m above the soil surface to facilitate welding of the pile body section 10.

[0138] Step 2-2, the pile body section 10 is then placed above the pile tip section 20 by hoisting, so that the lower end of the pile body section 10 and the upper end of the pile tip section 20 are attached, docked and calibrated;

[0139] At this time, since the longitudinal ends of the pile body section 10 and the pile tip section 20 are provided with edge chamfers 50, a V-shaped welding joint is formed after the longitudinal ends are butt-jointed, and the welding joint is used for welding, and it is ensured that the weld is continuous and full without bubbles or cracks;

[0140] Step 2-3, after the welded part is cooled naturally, a pile cap 30 is placed on the upper end of the pile body section 10 and driven until the upper end of the pile body section 10 is at least 0.5m above the soil surface, and then the pile cap 30 is removed;

[0141] The upper pile body section 10 and the lower pile body section 10 are welded at the edge chamfer 50;

[0142] Step 2-4, hoisting other pile sections 10 to the lower pile section 10, repeating steps 2-3 until all pile sections 10 are driven into the soil, completing the driving of a whole pile;

[0143] When the uppermost pile body section 10 is driven into the soil, the pile cap 30 is welded to the uppermost pile body section 10 to ensure the integrity of the pile body;

[0144] When the driving is stopped, the brim of the pile cap 30 contacts and compacts the soil surface below, so as to ensure the pile cap 30 protects the internal structure of the pile body 10 .

[0145] An exemplary implementation of a steel sheet pile with a negative Poisson's ratio proposed in the present invention is described in detail above with reference to a preferred embodiment. However, those skilled in the art will appreciate that, without departing from the concept of the present invention, various modifications and variations may be made to the above-mentioned specific embodiments, and various technical features and structures proposed in the present invention may be combined in various ways without exceeding the protection scope of the present invention, which is determined by the appended claims.

Claims

1. A steel sheet pile with a negative Poisson's ratio, comprising a pile cap (30), at least one pile body section (10), and a pile tip section (20) connected in sequence from top to bottom; It is characterized in that The pile body section (10) and the pile tip section (20) are both shell structures, and the horizontal cross section of the pile body section (10) is consistent with the horizontal cross section of the upper part of the pile tip section (20); The two longitudinal ends of the pile body section (10) are arranged in parallel and spaced apart, and the middle parts of the two transverse ends are bent toward the center of the pile body section (10), so that the pile body section (10) forms an hourglass-shaped structure in a horizontal cross section; The wall thickness of the pile body section (10) and the pile tip section (20) are filled with negative Poisson's ratio material (40); The lower part of the pile tip section (20) extends downward along the transverse end of the upper part to form a lower end sharp corner (22) structure.

2. A steel sheet pile with a negative Poisson's ratio according to claim 1, characterized in that: The pile body section (10) and the pile tip section (20) are respectively provided with a first slot hole (11) and a second slot hole (21) along a circumferential closed loop; The centers of the first slot hole (11) and the second slot hole (21) are consistent with the center of the wall thickness, and the upper ends are open and the lower ends are closed; The negative Poisson's ratio material (40) is filled in the first slot (11) and the second slot (21).

3. A steel sheet pile with a negative Poisson's ratio according to claim 2, characterized in that: The length of each longitudinal end of the pile body section (10) is equal to the distance between a pair of longitudinal ends; The included angle β between the transverse end and the longitudinal end of the pile body section (10) is 65°-75°.

4. A steel sheet pile with a negative Poisson's ratio according to claim 2, characterized in that: The relationship between the distance h1 from the first slot (11) to the bottom end of the pile body section (10) and the overall height h of the pile body section (10) is: h1=(0.1~0.15)h The relationship between the distance h2 from the second slot (21) to the bottom end of the pile tip section (20) and the outer length a of the longitudinal end of the pile tip section (20) is: Wherein, α is the angle between the tip angle (22) at the lower end of the pile tip section (20) and the horizontal plane, and is set to be 45°-50°; The relationship between the width t1 of the first slot hole (11) and the second slot hole (21) and the outer length a of the longitudinal end of the pile body section (10) is: t1=(0.04~0.1)a.

5. A steel sheet pile with a negative Poisson's ratio according to any one of claims 1 to 4, characterized in that: The transverse ends between adjacent pile body sections (10) and the longitudinal ends of the pile body sections (10) adjacent to the pile tip section (20) are both provided with edge chamfers (50).

6. A steel sheet pile with a negative Poisson's ratio according to any one of claims 1 to 4, characterized in that: The radius of the outer rounded corner R1 where the lateral end and the longitudinal end of the pile shaft section (10) are connected is the same as the radius of the outer rounded corner R2 where the middle part of the lateral end of the pile shaft section (10) is bent, and R1=R2=0.05a Wherein, a is the outer length of the longitudinal end of the pile body section (10); The radius of the fillet R3 on the inner side where the lateral end of the pile body section (10) is connected to the longitudinal end and close to the first slot hole (11) is the same as the radius of the fillet R4 on the inner side where the middle part of the lateral end of the first slot hole (11) is bent and close to the first slot hole (11), and R3=R4=0.05c Wherein, c is the inner length of the longitudinal end of the pile body section (10).

7. A steel sheet pile with a negative Poisson's ratio according to claim 4, characterized in that: The pile cap (30) comprises a pile eave (31) and a positioning assembly located below the pile eave (31); When driving, the positioning assembly is used to limit the upper end of the pile body section (10) or the pile tip section (20).

8. A steel sheet pile with a negative Poisson's ratio according to claim 7, characterized in that: The positioning assembly is an arc-shaped structure and is located at the connection between the transverse end and the longitudinal end of the pile body section (10). The positioning assembly comprises a first positioning plate (32) and a second positioning plate (33) of an arc-shaped structure. The first positioning plate (32) can contact the inner side of the pile body section (10), and the second positioning plate (33) can contact the outer side of the pile body section (10).

9. A steel sheet pile with a negative Poisson's ratio according to claim 7, characterized in that: The inner edge of the pile eave (31) extends inwardly at an equal distance relative to the inner contour of the pile body section (10), and the outer edge extends outwardly at an equal distance relative to the outer contour of the pile body section (10); The relationship between the upper and lower thickness h3 of the pile cap (30) and the thickness h1 from the first slot hole (11) to the bottom end of the pile body section (10) is: h3 = (1 ~ 1.2) h1.

10. A construction method for a steel sheet pile with a negative Poisson's ratio according to claim 2, characterized in that: The specific steps include: Step 1, clean up the pile sinking point; Step 2, transporting the steel sheet pile with negative Poisson's ratio as claimed in claim 2 to the vicinity of the pile sinking point and performing pile sinking operation; Step 2-1, firstly, the pile tip section (20) is arranged vertically and aligned with the pile sinking point, and a pile cap (30) is placed on the upper part of the pile tip section (20) to ensure that the pile body is evenly compressed, and the pile tip section (20) is driven until the upper end is at least 0.5m above the soil surface, and then the pile cap (30) is removed; Step 2-2, placing the pile body section (10) above the pile tip section (20) so that the lower end of the pile body section (10) and the upper end of the pile tip section (20) are closely connected and aligned; Welding the longitudinal ends of the pile body section (10) and the pile tip section (20); Step 2-3, after the welding is naturally cooled, a pile cap (30) is placed on the upper end of the pile body section (10) and driven until the upper end of the pile body section (10) is at least 0.5m above the soil surface, and then the pile cap (30) is removed; The upper pile body section (10) and the lower pile body section (10) are welded at the butt joint at the longitudinal ends; Step 2-4, connecting other pile sections (10) to the pile sections (10) below in sequence, and repeating steps 2-3 until all the pile sections (10) are driven into the soil, thereby completing the driving of the steel sheet pile with a negative Poisson's ratio; When the uppermost pile body section (10) is driven into the soil, the pile cap (30) is welded to the uppermost pile body section (10) to ensure integrity; When the driving is stopped, the brim of the pile cap (30) contacts and compacts the soil surface below, so as to ensure the pile cap (30) protects the internal structure of the pile body (10).

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